Mount Mazama Ash Offers Sustainable Solution for ADA Accessibility on Unpaved Trails

National Institute for Transportation and Communities (NITC) researcher Matthew Sleep of Oregon Tech investigated whether Mazama ash could be used in place of portland cement, as a natural pozzolan. Results indicate that it can—and unpaved trail surfaces made with Mazama ash are actually firmer and more durable than those made with portland cement alone. Such trails can provide a reliable surface for wheeled mobility devices

Optimization of Adaptation - A Multi-objective Approach for Optimizing Changes to Design Parameters

Dynamic optimization problems require constant tracking of the optimum. A solution for such a problem has to be adjustable in order to remain optimal as the optimum changes. The manner of changing design parameters to predefined values is dealt with in the field of control. Common control approaches do not consider the optimality of the design, in terms of the objective function, while adjusting to the new solution. This study highlights the issue of the optimality of adaptation, and defines a new optimization problem – ”Optimization of Adaptation”. It is a multiobjective problem that considers the cost of the adaptation and the optimality while the adaptation takes place. An evolutionary algorithm is proposed in order to solve this problem, and it is demonstrated, first, with an academic example, and then with a real life application of a robotic arm control

The Temperature and Pressure Dependence of Nickel Partitioning between Olivine and Silicate Melt

We measured Ni partitioning between olivine and melt, D^(ol/liq)_(Ni), in experiments on mid-ocean ridge basalt (MORB) encapsulated in olivine at pressures from 1 atm to 3·0 GPa and temperatures from 1400 to 1550°C. We present a series of experiments where the temperature (T) at each pressure (P) was selected so that the liquid composition remained approximately constant over the entire P–T range. This approach allowed us to investigate the effects of T and P on D^(ol/liq)_(Ni), independent of substantial changes in liquid composition. Our experiments show that for a liquid with ∼18 wt% MgO, D^(ol/liq)_(Ni) decreases from 5·0 to 3·8 as the temperature increases from 1400 to 1550°C. Fitting our experimental results and literature data to thermodynamic expressions for D^(ol/liq)_(Ni) as a function of both temperature and liquid composition shows that the small variations in liquid composition in our experiments account for little of the observed variation of D^(ol/liq)_(Ni). Because the changes in volume and heat capacity of the exchange reaction MgSi_(0-5)O^(ol)_2 + D^(ol/liq)_(Ni) ↔ NiSi_(0-5)O^(ol)_2 + MgO^(liq) are small, D^(molar)_(Ni), the Ni partition coefficient on a molar basis, is well described by In(D^(molar)_(Ni))=-^(Δ_rHo_(T_(ref)),P_(ref)/_(RT) + ^Δ_rSo_(T_(ref),P_(ref))/_R - In (X^(liq)_(MgO)/X^(ol)_(MgSi)_(0-5)O_2) with Δ_rH^o_T_(ref),_P_(ref)/_R = 4375 K and Δ_rSo_T_(ref),_P_(ref)/_R = –2·023 for our data (Δ_rH^o_T_(ref),_P_(ref)/_R = 4338 K and Δ_rSo_T_(ref),_P_(ref)/_R = –1·956 for our experiments combined with a compilation of literature data). This expression is easy to use and applicable to a wide range of pressures, temperatures, and phase compositions. Based on our results and data from the literature, the temperature dependence of D^(ol/liq)_(Ni) leads to the prediction that when a deep partial melt from a peridotitic mantle source is brought to low pressure and cooled, the first Mg-rich olivines to crystallize can have significantly higher NiO contents than those in the residual source from which the melt was extracted. This enrichment in Ni is driven by the difference between the temperature of low-pressure crystallization and the temperature of melt extraction from the residue. The average observed enrichment of Ni in forsteritic olivine phenocrysts from Hawaii—relative to the typical olivines from mantle peridotites—is consistent with a simple scenario of high-temperature partial melting of an olivine-bearing source at the base of the lithosphere followed by low-temperature crystallization of olivine. The most extreme enrichments of Ni in Hawaiian olivine phenocrysts and the lower Ni contents of some olivines can also be explained by the known variability of Ni contents of olivines from mantle peridotites via the same simple scenario. Although we cannot rule out alternative hypotheses for producing the high-Ni olivines observed in Hawaii and elsewhere, these processes or materials are unnecessary to account for NiO enrichments in olivine. The absolute temperature, in addition to the difference between the temperature of melt segregation from the residue and the temperature of low-pressure crystallization, is a significant factor in determining the degree of Ni enrichment in olivine phenocrysts relative to the olivines in the mantle source. The moderate Ni enrichment observed in most komatiitic olivines compared with those of Hawaii may result from the higher absolute temperatures required to generate MgO-rich komatiitic melts. Observed NiO enrichments in early crystallizing komatiitic olivine are consistent with their high temperatures of crystallization and with a deep origin for the komatiite parental melts

Fe-Mg Partitioning between Olivine and High-magnesian Melts and the Nature of Hawaiian Parental Liquids

We conducted 1 atm experiments on a synthetic Hawaiian picrite at fO_2 values ranging from the quartz–fayalite–magnetite (QFM) buffer to air and temperatures ranging from 1302 to 1600°C. Along the QFM buffer, olivine is the liquidus phase at ~1540°C and small amounts of spinel (< 0·2 wt %) are present in experiments conducted at and below 1350°C. The olivine becomes progressively more ferrous with decreasing temperature [Fo_(92·3) to Fo_(87·3), where Fo = 100 × Mg/(Mg + Fe), atomic]; compositions of coexisting liquids reflect the mode and composition of the olivine with concentrations of SiO_2, TiO_2, Al_(2)O_3, and CaO increasing monotonically with decreasing temperature, those of NiO and MgO decreasing, and FeO^* (all Fe as FeO) remaining roughly constant. An empirical relationship based on our data, T(°C) = 19·2 × (MgO in liquid, wt %) + 1048, provides a semi-quantitative geothermometer applicable to a range of Hawaiian magma compositions. The olivine–liquid exchange coefficient, K_(D,Fe^(2+)-Mg) = (FeO/MgO)^(ol)/(FeO/MgO)^(liq), is 0·345 ± 0·009 (1σ ) for our 11 experiments. A literature database of 446 1 atm experiments conducted within 0·25 log units of the QFM buffer (QFM ± 0·25) yields a median K_(D,Fe^(2+)-Mg) of 0·34; K_(D,Fe^(2+)-Mg) values from single experiments range from 0·41 to 0·13 and are correlated with SiO_2 and alkalis in the liquid, as well as the forsterite (Fo) content of the olivine. For 78 experiments with broadly tholeiitic liquid compositions (46–52 wt % SiO_2 and ≤ 3 wt % Na_(2)O + K_(2)O) coexisting with Fo_(92–80) olivines, and run near QFM (QFM ± 0·25), K_(D,Fe^(2+)-Mg) is approximately independent of composition with a median value of 0·340 ± 0·012 (error is the mean absolute deviation of the 78 olivine–glass pairs from the database that meet these compositional criteria), a value close to the mean value of 0·343 ± 0·008 from our QFM experiments. Thus, over the composition range encompassed by Hawaiian tholeiitic lavas and their parental melts, K_(D,Fe^(2+)-Mg) ~ 0·34 and, given the redox conditions and a Fo content for the most magnesian olivine phenocrysts, a parental melt composition can be reconstructed. The calculated compositions of the parental melts are sensitive to the input parameters, decreasing by ~1 wt % MgO for every log unit increase in the selected fO_2, every 0·5 decrease in the Fo-number of the target olivine, and every 0·015 decrease in K_(D,Fe^(2+)-Mg). For plausible ranges in redox conditions and Fo-number of the most MgO-rich olivine phenocrysts, the parental liquids for Hawaiian tholeiites are highly magnesian, in the range of 19–21 wt % MgO for Kilauea, Mauna Loa and Mauna Kea

Exploring the parameter space of MagLIF implosions using similarity scaling. III. Rise-time scaling

Magnetized Liner Inertial Fusion (MagLIF) is a z-pinch magneto-inertial-fusion (MIF) concept studied on the Z Machine at Sandia National Laboratories. Two important metrics characterizing current delivery to a z-pinch load are the peak current and the current-rise time, which is roughly the time interval to reach peak current. It is known that, when driving a z-pinch load with a longer current-rise time, the performance of the z-pinch decreases. However, a theory to understand and quantify this effect is still lacking. In this paper, we utilize a framework based on similarity scaling to analytically investigate the variations in performance of MagLIF loads when varying the current-rise time, or equivalently, the implosion timescale. To maintain similarity between the implosions, we provide the scaling prescriptions of the experimental input parameters defining a MagLIF load and derive the scaling laws for the stagnation conditions and for various performance metrics. We compare predictions of the theory to 2D numerical simulations using the radiation, magneto-hydrodynamic code HYDRA. For several metrics, we find acceptable agreement between the theory and simulations. Our results show that the voltage near the MagLIF load follows a weak scaling law $\smash{\varphi_{\rm load} \propto t_\varphi^{-0.12}}$ with respect to the characteristic timescale $t_\varphi$ of the voltage source, instead of the ideal $\smash{\varphi_{\rm load} \propto t_\varphi^{-1}}$ scaling. This occurs because the imploding height of the MagLIF load must increase to preserve end losses. As a consequence of the longer imploding liners, the required total laser preheat energy and delivered electric energy increase. Overall, this study may help understand the trade-offs of the MagLIF design space when considering future pulsed-power generators with shorter and longer current-rise times.Comment: 15 pages, 20 figures, submitted to Phys. Plasmas. arXiv admin note: text overlap with arXiv:2209.1491

The Use of Maintenance Electroconvulsive Therapy for Relapsing Depression

It is generally accepted that electroconvulsive therapy (ECT) is an effective treatment of major depressive episodes in patients with both unipolar and bipolar affective disorders (1). Yet, repeated relapse of depression occurs in some patients, even with vigorous maintenance therapy on antidepressant drugs (2-4). This often necessitates rehospitalization for ECT. In past decades, several authors suggested that periodic outpatient ECT was efficacious as a maintenance therapy (5-7). Recently, maintenance ECT was recommended by Fink (8), and Maletzky (9), but barely mentioned in two reviews (10,11), and discouraged in another (12) . However, a recent nationwide survey has disclosed that such therapy is widely practiced (13)

EuroBarley:control of leaf diseases in barley across Europe

Barley crops are at risk of being attacked by several leaf diseases. Net blotch, brown rust, Rhynchosporium and Ramularia leaf spot are among the most widespread and can cause severe attack and yield losses. Two trial protocols targeting Ramularia and net blotch, respectively, have been tested in several countries in 2021 and 2022. Ramularia trials were situated in Germany, Ireland, Scotland, and Denmark. The net blotch trials were placed in Denmark, Belgium, the UK, Germany, Finland, and France. In the two protocols, 12–13 different fungicide solutions including co-formulations of DMIs, SDHIs, QoIs, and multi-site inhibitors have been tested to compare efficacy and yield responses. Against Ramularia leaf spot, the fungicides were applied at GS 47–51 and against net blotch at GS 37–45. In six trials, the efficacy against Ramularia leaf spot was scored. The results showed a superior control from the co-formulation fluxapyroxad + metyltetraprole (78–100% control), but also solo mefentrifluconazole and the mixtures fluxapyroxad + mefentrifluconazole performed well (average 74–76% control). The mixture fluxapyroxad + metyltetraprole provided the best yield increase followed by Ascra Xpro. Folpet as a solo solution was inferior. Following the net blotch protocol, only three trials developed enough disease to rank the different fungicides; however, in five trials ranking against brown rust was also possible. Most treatments gave very good control of net blotch, and brown rust (&gt; 80% control). The mixture fluxapyroxad + metyltetraprole delivered the best control against all diseases overall. Average yield responses from eight trials showed very similar increases from the tested fungicides.</p