RbF post-deposition treatments have been explored in the literature for increasing the open-circuit voltage, fill factor, and hence the efficiency of Cu(In,Ga)Se2 solar cells. However, given the few ...papers documenting the experimental steps, it was difficult to quickly reproduce the results. This contribution describes some of the optimization steps that led to a successful RbF PDT based on device performance. Here we present results that put boundaries on the temperatures of the RbF cell and the lamp (for sample heating) setpoint. The best recipe for our specific growth process is documented in detail so that others may copy the procedure and possibly arrive at a successful RbF PDT in a reasonable time.
The influence of clay-layer spacing on gas barrier thin films of sodium montmorillonite clay and polyelectrolytes, created via layer-by-layer assembly, is investigated. The alternate deposition of ...polymers and clay leads to the assembly of a nanobrick wall structure that is highly impermeable to gases. In an effort to tailor the thickness (or spacing) between clay layers, films with differing numbers of polymer layers between clay depositions were examined. Films analyzed for their thickness, clay concentration, transparency, nanostructure, and oxygen barrier as a function of layers (or spacing) between clay depositions reveal linear growth, optical clarity, and low OTR at 100 nm thick and containing only four clay layers. An optimal thickness between clay layers appears to exist for achieving the highest oxygen barrier LbL films (PO2 < 1 × 10–21 cc(STP)·cm/(cm2·s·Pa)). This knowledge can ultimately minimize deposition steps and lead to decreased thin film fabrication times.
•No-till produced similar yield and quality of sugarbeet compared to conventional tillage.•No-till saved US$111 per ha in tillage costs compared to conventional tillage.•Sugarbeet root yield ...increased linearly with increasing nitrogen input, but impurity also increased.•Sugarbeet sucrose concentration decreased with increasing nitrogen input.
Conventional intensive tillage (CT) is widely practiced in sugarbeet (Beta vulgaris L.) growing regions. However, CT uses more labor and machinery and has negative impacts on soil and environment. Limited information exists for the performance of sugarbeet in reduced tillage compared to CT systems. A three-year field experiment was conducted to evaluate yield and quality of sugarbeet under no-till (NT), and strip-till (ST) systems compared to CT. The response of sugarbeet to the increasing rate of nitrogen (N) from 56 to 224 kg ha−1 in each tillage system was also studied. Sugarbeet plant stand, root yield, root impurities (sodium, potassium, and amino-N concentration in the root), sucrose loss to molasses (SLM) and recoverable sucrose yield were measured. Tillage had no significant effect on plant stand, root yield, and recoverable sucrose yield. The estimated cost of tillage operation showed that growing sugarbeet under NT was 111 US$ ha−1 less than that in CT, which could be translated into 111 US$ ha−1 higher net benefit for growers considering the similar yields in both systems. Sugarbeet root yield linearly increased in response to increasing rate of N, however, sucrose concentration decreased and root impurities increased with increasing N input. Overall, little increase of recoverable sucrose yield was observed with N rate increasing from 56 to 224 kg ha−1. Response to N rate occurred irrespective of tillage method.
In an effort to protect polyurethane foam (commonly used as cushioning in upholstered furniture) from fire using environmentally benign chemistries, nanocomposite thin films are deposited using ...water‐based solutions of cationic‐ and anionic‐stabilized multiwalled carbon nanotubes (MWCNTs). The open‐celled foam is coated using layer‐by‐layer (LbL) assembly to produce uniform protective layers up to 600 nm thick, comprised of cationic polyethylenimine modified with pyrene (PEI‐Py), anionic poly(acrylic acid) (PAA), and MWCNT. Film thickness is found to rely heavily on the PAA‐stabilized MWCNT solution. Coatings of only six PEI‐Py/PAA+MWCNT bilayers (BL) show tremendous reductions in peak heat release rate (up to 67%) and total smoke release (up to 80%) for the polyurethane foam. This same coating significantly improves the performance of the polyurethane when exposed to horizontal and vertical flame tests. With 9 BL, the foam successfully withstands a vertical burn test, self‐extinguishing immediately after removal of the test flame. These dramatic reductions in foam flammability are unprecedented and are attributed to the protective nature of the carbon‐based char formed from the coating that acts as a protective barrier.
A layer‐by‐layer nanocoating combining polymers and multiwalled carbon nanotubes renders polyurethane foam flame retardant. Pyrene‐modified polyethylenimine and poly(acrylic acid) are used to stabilize multiwalled carbon nanotubes in water‐based solutions to create nanocomposite thin films on polyurethane foam. These thin films dramatically reduce the flammability of polyurethane foam during cone calorimetry and open flame tests.
Tillage practices can influence the pore size distribution (PSD) of the soil, affecting soil physical and hydraulic properties as well as processes that are essential for plant growth, soil ...hydrology, environmental studies and modeling. A study was conducted to assess the effect of no-tillage (NT) and conventional tillage (CT) on PSD derived from soil–water retention curves (SWRCs) using the van Genuchten’s equation (vG) at 0–15 cm and 15–30 cm depths in a sandy loam soil. Values of PSD or slopes (C(h)) were calculated from the SWRCs by differentiating the vG equation. Soil water retention curves under both tillage systems and within two depths were determined using the evaporation HYPROP method. The vG equation was well fitted to measured soil water retention data. The diameter (D) of soil pores retaining water at various matric suctions (|h|) of water in soils was calculated by the capillary equation. A significant effect of tillage on soil PSD was observed in the macro-pore (D > 1000 μm, at |h| < 3 hPa) and meso-pore (D between 10 and 1000 μm, at |h| between 300 and 3 hPa) size classes, while the micro-pores size class (D < 10 μm, at |h| > 300 hPa) was unaffected at the 0–15 and 15–30 cm depths. Larger values of C(h) or PSD in CT were associated with greater soil loosening induced by the CT operations and greater proportion of large pores (structural porosity) occurred in soils under CT compared to soils under NT. Macro-pore and meso-pore proportions were significantly greater in soils under CT than in soils under NT within both soil depths. The hydraulic parameters of the vG equation and its derivative function can be used to compare soil–water retention curves and pore size distributions between soils under untilled and tilled conditions.
Layer-by-layer assembly from aqueous solutions was used to construct multilayer thin films (<200 nm) comprising polyethylenimine and graphene oxide. Low-temperature (175 °C) thermal reduction of ...these films improved gas barrier properties (e.g., lower permeability than SiO x ), even under high humidity conditions, and enhanced their electrical conductivity to 1750 S/m. The flexible nature of the aforementioned thin films, along with their excellent combination of transport properties, make them ideal candidates for use in a broad range of electronics and packaging applications.
Many shank-type strip tillage (ST) implements band fertilizer below the seed without incorporating crop residue into the soil, potentially affecting N availability. Sprinkler irrigation method may ...also affect N availability due to its influence on water and NO3–N movement in soil. A field study was conducted at Sidney, MT, to determine if sugarbeet (Beta vulgaris L.) petiole NO3–N concentration and soil available (i.e., mineral) N distribution differ under (i) conventional tillage (CT) and ST systems and (ii) mid-elevation spray application (MESA) and low energy precision application (LEPA) irrigation methods. Mid-season petiole NO3–N concentration was lower with ST than with CT in 1 of 3 yr. In-season mineral N concentration in the top 45 cm of soil was lower with ST than with CT. Postharvest mineral N was 10% lower with ST than with CT. There were few measurable effects of irrigation method except that in-season mineral N in the top 45 cm of soil was 10% greater with LEPA than with MESA. Root yield and sugar production were reported to be similar with the two tillage systems. It was concluded that differences in petiole NO3–N concentration and soil mineral N content were not sufficient to justify altering N application rate based on the tillage systems or irrigation methods evaluated. However, there were indications that NO3–N leaching may be reduced by combining LEPA, with which irrigation water is applied between alternating crop rows, with strip tillage, where N is banded beneath the crop row.
Macromol. Mater. Eng. 6/2016 Holder, Kevin M.; Cain, Amanda A.; Plummer, Morgan G. ...
Macromolecular materials and engineering,
06/2016, Volume:
301, Issue:
6
Journal Article
Peer reviewed
Open access
Front Cover: A multilayer nanocoating composed of polyelectrolytes and carbon nanotubes is able to render polyurethane foam flame retardant. This cover image represents the potential to protect ...household furniture from fire using this simple water‐based coating. Further details can be found in the article by Kevin M. Holder, Amanda A. Cain, Morgan G. Plummer, Bart E. Stevens, Patrick K. Odenborg, Alexander B. Morgan, and Jaime C. Grunlan* on page 665.
Irrigation is important to sugarbeet (Beta vulgaris L.) production and efficient irrigation management is critical for yield, sugar concentration, water use, and environment quality. Two irrigation ...studies were conducted to investigate sugarbeet response to deficit irrigation under conventional tillage (CT) and no‐till (NT) systems in 2016 and 2018. The irrigation treatments included full irrigation (100% crop evapotranspiration, 100ETc) and deficit irrigation (66% crop evapotranspiration, 66ETc), and two irrigation cutoff dates (15 and 30 d before harvest). Plant population, soil moisture, sugarbeet root yield, sucrose concentration, and impurity value were measured. Although deficit irrigation at 66ETc did not affect the sugarbeet root yield, sucrose concentration, and sugar yield in 2016, it reduced the root yield, sugar yield, and extractable sugar yield by 5.5, 1.2, and 1.2 Mg ha−1 under CT and 12.4, 2.1, and 1.9 Mg ha−1 under NT systems in 2018. Soil moisture in NT showed great depletion at 15‐ and 38‐cm depths in July and August in 2018. Results indicate the potential of implementing a deficit irrigation strategy in sugarbeet to reduce the water supply and increase the water use efficiency, but in‐situ soil moisture sensors should be installed to monitor soil moisture to avoid severe water stress. Stopping irrigation 30 d before harvest slightly reduced the sugarbeet root yield but did not affect extractable sugar yield, suggesting that omitting one irrigation late in the growing season may not reduce root yield and quality. Deficit irrigation in conjunction with a no‐till system could reduce production costs and bring environmental benefits.
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