Several publications and web-based tools are available in weed science literature to help weed scientists to carry out basic analysis of dose-response studies. Given the nature of the complicated relationship between the explanatory variable (dose as x-axis) evaluated against response variables of interest (y-axis), using regression curves should be the preferred method for handling data analysis. The objective of this manuscript is to provide user-friendly instructions for conducting and analyzing several types of dose-response studies that were lacking in current weed science literature. A better understanding of less commonly used concepts of hormesis and toxicological safety thresholds (no-observable-adverse-effect-level [NOAEL] and lowest-observable-adverse-effect-level [LOAEL]) is needed to help address the potential risks and benefits associated with herbicide use while minimizing environmental impacts. Basic codes available in cost-free R software are provided for data analysis and to foster collaboration among weed scientists.

Bentonite is to be used as a sealing material for long-term storage of radioactive waste. During permafrost periods the buffer may freeze, causing the following: montmorillonite dehydration, ice formation, and pressure build-up that may fracture the surrounding rock. No previous study has been done on freezing of bentonite in saline water. Using small and wide angle X-ray scattering, the present study aimed to increase understanding of the combined impact of salt and temperature on the hydration (swelling) of Wyoming montmorillonite. The basal spacing of the Na-montmorillonite was very dependent on the water content, while this was not the case for the Ca-montmorillonite (after reaching 19 Å). The basal spacing of the free-swelling Na-montmorillonite (34–280 Å) was estimated successfully using simple calculations. During freezing of Na-montmorillonite in NaCl solution, both ice and hydrohalite formed (at -50 and -100ºC). At starting concentrations ≥ 1.5 M the basal spacing was not affected by freezing. During freezing of Ca-montmorillonite in CaCl2 solution, ice formed; antarcticite formed only sporadically. The basal spacing of the Ca-montmorillonite at high NaCl concentrations (>1 M) was greater at -50 and -100ºC (18 Å) than at 20ºC (16 Å). The opposite was observed at low concentrations. This change was attributed to small amounts of salts introduced into the montmorillonite interlayer, hence changing the interlayer water properties. The montmorillonite hydration was also temperature dependent; decreasing temperature increased the hydration (as long as no ice was formed) and increasing the temperature decreased the hydration. This was attributed to the temperature impact on the entropy of the hydration reaction. This observation was also reproduced in an experiment up to 90ºC. A small amount of salt in the groundwater was noted to reduce significantly the potential problem of ice formation in bentonite sealings.

Few studies have assessed the association between sodium (Na) and potassium (K) and migraine headaches. In this study, we aimed to examine the relationship between 24-hour urine Na and K intakes and clinical findings of migraine in an Iranian sample. In this cross-sectional study, 262 participants, aged 20–50 years, were included with a body mass index (BMI) of 18·5–30 kg/m2 and a diagnosis of migraine. One 24-hour urine sample was collected from each subject to estimate the Na and K intakes. The clinical features of migraine, including frequency, duration, severity, Migraine Headache Index Score (MHIS), and Headache Impact Test (HIT) score, were assessed. Besides, a multiple linear regression analysis was performed, and beta estimates and the corresponding 95% confidence intervals (CIs) were reported. Overall, 224 women and 38 men, with a mean age of 36·10 years and BMI of 25·55 kg/m2 comprised our study population. After controlling for potential confounders, the 24-hour urine Na was positively associated with a longer headache duration (β = 0·29; 95% CI: 0·06, 0·53) in the group with the highest urine Na levels as compared to the group with the lowest levels. After adjustments for potential confounders, an increase of 13·05 in the MHIS was observed when the 24-hour urine Na level increased from the first to the third tertile (β = 13·05; 95% CI: 1·70, 24·41). Our findings suggested that a higher 24-hour urine Na level was positively associated with a longer duration of migraine headaches and a higher MHIS.

We investigate, from first principles, the electrochemical sodiation mechanism of rutile-type vanadium dioxide as a possible electrode material for sodium-ion batteries. The computed voltages versus sodium metal are low in comparison to current state-of-the-art sodium-ion battery cathodes, which we can relate to the large space demand of sodium ions in the compact rutile structure and the resulting severe lattice deformations compared to other working metals. Due to the same reason large anisotropic unit cell volume changes are predicted during cycling. We furthermore find a change of the preferred reaction mechanism during discharge, with a switching between insertion- and conversion-type reaction at higher degrees of sodiation. The predicted capacities on the other hand are appreciable, making a further consideration of this material as high-potential anode in combination with sodium working metal interesting.

29Si, 27Al MAS NMR is used to characterize Laponite RD and synthetic saponites of variable interlayer charge. The Si/Al ratios are in good agreement with the calculated charge from chemical analysis except for the lowest-charged saponite. In contrast to the 29Si MAS NMR spectra in which resolved signals are detected, the 27Al MAS NMR spectra show one signal whose linewidth increases with the clay charge. The water content of the clay samples was obtained from 1H MAS NMR.

The 2D MQMAS NMR technique is required to obtain a high-resolution spectrum of nuclei with strong quadrupolar interaction. This method was applied to the 23Na nucleus of clay counterions and to the 27Al structural nucleus. One well-defined 23Na NMR signal is observed for all the clays studied except the highest-charged saponite. Possible explanations for this different behaviour are discussed. The calculated isotropic chemical shift evolves progressively with the clay charge whereas the deduced quadrupolar interaction does not change significantly. The 27Al 2D 3QMAS technique was not able to resolve more than one signal.

The [AlO4/M+]0 (where M = H, Li, Na and K) defects in α-quartz have been investigated by ab initio calculations at the density functional theory (DFT) level, using the CRYSTAL06 code, 72-atom supercells, and all-electron basis sets. Our DFT calculations yielded substantially improved results than previous cluster calculations with minimal basis sets. For example, the [AlO4/M+(a<)]0 defects with M = H, Li and Na have been shown to be more stable than their [AlO4/M+(a>)]0 structural analogues (where a> and a< denote the location of the charge-compensating ion on the long-bond and short-bond side respectively), correctly predicting the common occurrence of paramagnetic [AlO4/M+(a>)]+ centres. In addition, the [AlO4/K+]0 defects have been investigated for the first time and are shown to be stable in quartz. Moreover, our calculations confirm previous suggestions that incorporation of the [AlO4/M+]0 defects results in significant structural relaxations that extend at least to the nearest Si atoms and give Li—O and Na—O bond distances in better agreement with the experimentally obtained values. The present theoretical results on the [AlO4/M+]0 defects provide a more complete picture for the coupled Al3+—M+ substitutions and hence new insights into crystal-chemical controls on the uptake of Al in quartz.

Greenhouse studies were initiated to determine the efficacy of four herbicide antidotes as protectants of corn (Zea mays L., ‘DeKalb XL72AA’ and ‘DeKalb XL67′) against injury from preemergence or early postemergence applications of the herbicides chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] benzenesulfonamide}, fluazifop-butyl {butyl-2-[4-[5-(trifluoromethyl-2-pyridinyl)oxy] phenoxy] propanoate}, or BAS 9052 OH {2-[1-(ethoxyimino)-butyl]-5-[2-(ethylthio)-propyl]-3-hydroxy-2-cyclohexene-1-one}. NA (1,8-naphthalic anhydride) was the most effective of the four antidotes in protecting corn against injury from preemergence applications of chlorsulfuron. CGA-43089 [α-(cyanomethoxy)-imino-benzeneacetonitrile] and CGA-92194 [α-(1,3-dioxolan-2-yl-methoxy)-imino-benzeneacetonitrile] partially protected corn from chlorsulfuron injury, whereas R-25788 (N,N-diallyl-2,2-dichloroacetamide] was the least effective. R-25788 offered partial to good protection to corn against injury from preemergence applications of fluazifop-butyl and BAS 9052 OH. NA, or CGA-43089, and CGA-92194 partially protected corn from fluazifop-butyl injury but their efficacy against BAS 9052 OH injury to corn was limited. In general, all four antidotes offered better protection to the thiocarbamate-tolerant ‘XL72AA’ hybrid than to the thiocarbamate-susceptible ‘XL67’ hybrid. With the exception of NA, which partially protected corn from postemergence-applied chlorsulfuron, none of the four herbicide antidotes was effective in protecting corn against injury from postemergence applications of any of the three herbicides.

TMNCN (where TM = Mn2+, Fe2+, Co2+ or Ni2+) have been recently proposed as electrochemically active materials for Na-ion insertion that operate via conversion reaction. Their electrochemical performance for Na-ion batteries is presented here with an emphasis on long-term cycling. With a very low voltage for Na insertion of ∼0.1V vs Na+/Na for MnNCN, the overpotential observed in batteries of MnNCN plays a very important role in their performance, evidencing big differences in the electrochemical performance between materials produced with different nano- and micrometer particle sizes evidenced by SEM images. A more suitable voltage for the conversion reaction accompanied by less overpotential is shown by FeNCN, CoNCN and NiNCN. Despite the lower reversible capacity achieved by FeNCN (450 mAh/g) in comparison with CoNCN and NiNCN in the first cycle; the smallest first-cycle irreversible capacity (220 mAh/g) and the lower voltage plateau (0.3 V vs Na+/Na) make FeNCN a good candidate as an anode material for sodium ion batteries. The voltages of conversion reaction are correlated with the calculated enthalpies of formation suggesting that thermodynamics dominates the observed electrochemical conversion reaction.

Tin(Sn) and its alloys have been attracting attentions as a negative electrodematerial for sodium-ion secondary batteries with high theoretical capacity(Na15Sn4, ca. 847 mAh/g) and highelectromotiveforce. There still remains the issue as regards the dischargecapacity decrease with increasing the number of cycles. In order to improvecycle performance, there are many studies such as using Sn-Ni alloy, however,using Sn based alloy as negative electrode materials and it suffer from thedisadvantage of lowering of discharge capacity. In this study, a depositionprocess for making Sn film which consists of amorphous structure for negativeelectrode of sodium ion secondary batteries utilizing electordeposition fromaqueous bath was developed. The effect of additives on the surface morphologyand microstructure of Sn film was investigated. Furthermore, we evaluated theeffect of amorphous structure in the Sn film on cycle performance of the Snnegative electrode. Sn film has a good cycle characteristic (>50cycles) and discharge capacity (> 400 mAh/g). Amorphous structure inthe Sn film showed a microscopic effect on the volume change by sodiation anddesodiation.

Long wavelength acoustic phonons are normally weakly coupled to other vibrational modes in a crystalline system. This is particularly problematic in molecular dynamics calculations where vibrations at the system-size scale are typically excited at initiation. The equilibration time for these vibrations depends on the strength of coupling to other modes, so is typically very long. A very simple deterministic method is presented which removes this problem. Examples of equilibration in lithium and a martensitic phase transition in sodium are used to demonstrate the method.

High temperature solid state sodium (23Na) magic angle spinning (MAS) NMR spin lattice relaxation times (T1) were evaluated for a series of NASICON (Na3Zr2PSi2O12) materials to directly determine Na jump rates. Simulations of the T1 temperature variations that incorporated distributions in Na jump activation energies, or distribution of jump rates, improved the agreement with experiment. The 23Na NMR T1 relaxation results revealed that distributions in the Na dynamics were present for all of the NASICON materials investigated here. The 23Na relaxation experiments also showed that small differences in material composition and/or changes in the processing conditions impacted the distributions in the Na dynamics. The extent of the distribution was related to the presence of a disordered or glassy phosphate phase present in these different sol-gel processed materials. The 23Na NMR T1 relaxation experiments are a powerful tool to directly probing Na jump dynamics and provide additional molecular level details that could impact transport phenomena.

Considering the need for designing better batteries to meet the rapidly growing demand for large-scale energy storage applications, an aspect of primary importance for battery materials is elemental abundance. To achieve sustainable energy development, we must reconsider the feasibility of a sustainable lithium supply, which is essential for lithium(-ion) batteries. Lithium is widely distributed in the Earth, but is not regarded as an abundant element. Therefore, widespread use of large-scale lithium batteries would be inevitably restricted. Sodium(-ion) batteries are thus promising candidates for large-scale applications because sodium is the most advantageous next to lithium considering its atomic weight, standard potential, and natural abundance. Rechargeable sodium-ion batteries consist of two different sodium insertion materials similar to Li-ion batteries. Sodium insertion materials, especially layered oxides, have been studied since the early 1980s, but not extensively for energy storage devices due to the expanded interest in lithium insertion materials in the 1990s. In recent years, materials researchers have again been extensively exploring new sodium insertion materials to enhance battery performance. This article reviews recent advancements and trends in layered sodium transition metal oxides as positive electrode materials for Na-ion batteries.

This issue contains assessments of battery performance involving complex, interrelated physical and chemical processes between electrode materials and electrolytes. Transformational changes in battery technologies are critically needed to enable the effective use of renewable energy sources such as solar and wind to allow for the expansion of hybrid electric vehicles (HEVs) to plug-in HEVs and pure-electric vehicles. For these applications, batteries must store more energy per unit volume and weight, and they must be capable of undergoing many thousands of charge-discharge cycles. The articles in this theme issue present details of several growing interest areas, including high-energy cathode and anode materials for rechargeable Li-ion batteries and challenges of Li metal as an anode material for Li batteries. They also address the recent progress in systems beyond Li ion, including Li-S and Li-air batteries, which represent possible next-generation batteries for electrical vehicles. One article reviews the recent understanding and new strategies and materials for rechargeable Mg batteries. The knowledge presented in these articles is anticipated to catalyze the design of new multifunctional materials that can be tailored to provide the optimal performance required for future electrical energy storage applications.

“Abundance” is an important keyword in materials development. This is particularly the case for the energy storage sector, where materials themselves function as a storage host. The amount of materials is directly linked to the amount of energy stored in the device. In lithium (Li)-ion batteries, transition metal elements are necessary to accommodate a large number of electrons/holes in a reversible redox reaction. Iron, as the fourth most abundant element in the earth’s crust, is an ideal redox center, but practical storage electrodes with Fe redox have long been the “holy grail” of the Li-ion battery since its commercialization in 1991. In this article, the history of replacing Co with Fe in Li-battery electrodes is briefly reviewed followed by recent technical achievements toward more sustainable batteries using Na+ as a guest ion, where the goal would be to discover a high voltage electrode material composed of Na and Fe without compromising the energy density.

NaF precursor layers used for providing Na to Cu(In,Ga)Se2 (CIGS) grown on Na-free substrates have been studied. The NaF layers were deposited on top of the Mo back contact prior to the CIGS co-evaporation process. The co-evaporation process was interrupted after the preheating steps, and after part of the CIGS layer was grown. Completed samples were also studied. After the preheating, the NaF layers were analyzed with X-ray Photoelectron Spectroscopy and after growing part and all of the CIGS film, the Mo/NaF/CIGS stack was characterized using transmission electron microscopy (TEM) and secondary ion mass spectrometry (SIMS). The NaF layers were found to be stable in thickness and composition during the pre-heating in selenium containing atmosphere before the CIGS process. The TEM analyses on the partly grown samples show a layer at the CIGS/Mo interface, which we interpret as a partly consumed NaF layer. This is corroborated by the SIMS analysis. In finalized samples the results are less clear, but TEM images show an increased porosity at the position of the NaF layer.