Parallel Set Research Articles

Impact of tannic acid on nisin encapsulation in chitosan particles

This study investigates the effect of addition of tannic acid on nisin encapsulated in chitosan matrices. Composite materials were prepared using a mild, environmentally friendly procedure, ionotropic gelation of chitosan by sodium tripolyphosphate in the presence of nisin (N) at different concentrations. In two parallel sets of preparations, tannic acid (TA) was added at 10:1 and 5:1 N:TA, respectively. The obtained particles were characterized by FTIR, SEM, size, zeta potential, encapsulation efficiency, loading capacity, and ratio of residual free amino groups. The kinetics of nisin release from the particles was studied to assess the role of TA as a potential modulator thereof. Its addition resulted in enhanced release, higher at lower N:TA ratio. An additional benefit was that TA, a strong antioxidant, imparted antioxidant activity to the composites. Antimicrobial turbidimetric tests were performed against one gram-positive bacterium (Staphylococcus aureus) and two gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), all relevant for the food, pharmaceutical, and cosmetic industries. All the composites showed synergistic effects against all the bacteria tested. The positive coaction was stronger against the gram-negative species. This is remarkable since nisin by itself has not known activity against them.

Change-point testing for parallel data sets with FDR control

Large parallel data sets—consisting of paired measurements of responses and covariates—collected over time from numerous sources are ubiquitous. It is of great interest to identify the data sources where the underlying regression relationship of each data set has shifted. To be specific, the regression coefficient is changed to another one at some time point for each data set. Borrowing the strength of recent developments of multiple testing procedures, a residual-aggregated testing (RAT) method is proposed for recovering such data sources by controlling the false discovery rate (FDR). The proposed method can effectively incorporate the dependence structure among different data sets, and is more robust than the conventional Benjamini-Hochberg method based on asymptotic p-values or numerical approximations. Under mild conditions, the asymptotic validity for both the false discovery proportion and FDR control is established. Extensive numerical results further confirm the effectiveness and robustness of the proposed method.

Exact entanglement cost of quantum states and channels under positive-partial-transpose-preserving operations

This paper establishes single-letter formulas for the exact entanglement cost of simulating quantum channels under free quantum operations that completely preserve positivity of the partial transpose (PPT). First, we introduce the $\kappa$-entanglement measure for point-to-point quantum channels, based on the idea of the $\kappa$-entanglement of bipartite states, and we establish several fundamental properties for it, including amortization collapse, monotonicity under PPT superchannels, additivity, normalization, faithfulness, and non-convexity. Second, we introduce and solve the exact entanglement cost for simulating quantum channels in both the parallel and sequential settings, along with the assistance of free PPT-preserving operations. In particular, we establish that the entanglement cost in both cases is given by the same single-letter formula, the $\kappa$-entanglement measure of a quantum channel. We further show that this cost is equal to the largest $\kappa$-entanglement that can be shared or generated by the sender and receiver of the channel. This formula is calculable by a semidefinite program, thus allowing for an efficiently computable solution for general quantum channels. Noting that the sequential regime is more powerful than the parallel regime, another notable implication of our result is that both regimes have the same power for exact quantum channel simulation, when PPT superchannels are free. For several basic Gaussian quantum channels, we show that the exact entanglement cost is given by the Holevo--Werner formula [Holevo and Werner, Phys. Rev. A 63, 032312 (2001)], giving an operational meaning of the Holevo-Werner quantity for these channels.

Improved Recovery of Overloaded Anaerobic Batch Reactors by Graphene Oxide

Anaerobic digestion reactors may suffer from acidification when overloading occurs. Carbon-based materials are amended to mitigate the souring effects of excessive loading. This study aims to test if graphene oxide (GO) helps overloaded anaerobic reactors recover faster. Batch tests were conducted following a fed-batch strategy at different GO levels (0, 10, and 20 mg GO per g of volatile solid (VS)) and different inoculum substrate ratios (ISRs) of 2, 1, and 0.75 based on VS. While an ISR of 2 was initially applied, the ISR was decreased to 1 and 0.75 in two parallel sets of experiments to simulate overloading conditions at the fourth feeding cycle. Lastly, an ISR of 2 was restored in all assays. First-order model kinetic constants confirmed a significant (p < 0.05) effect by GO from the third feed on. Although the GO-amended assays did not alleviate the acidification effects, during the final phase the kinetic constants reached values similar to or even above the controls (without GO). Moreover, a GO concentration up to 20 mgGO/gVS had no impact on FOS/TAC. Overall, this study broadens the understanding of the design and operation of anaerobic reactors amended with GO.

Implementation of low-storage Runge-Kutta time integration schemes in scalable asynchronous partial differential equation solvers

The asynchronous computing method based on finite-difference schemes has shown promise in significantly improving the scalability of time-dependent partial differential equation (PDE) solvers by either relaxing data synchronization or avoiding communication between processing elements (PEs) on massively parallel machines. This method uses high-order accurate asynchrony-tolerant (AT) schemes coupled with appropriate time integration schemes to provide the desired accuracy required by high-fidelity solvers such as the direct numerical simulations for fluid flow. For time integration, Runge-Kutta (RK) schemes, particularly the low-storage implementation, are widely used due to their ability to provide good stability properties and be computationally efficient. However, the implementation of AT schemes with multi-stage RK schemes necessitates an over-decomposition of the spatial domain in a parallel setting, leading to increased message sizes for communication and redundant computations. In this paper, we propose a novel method to couple asynchrony-tolerant and low-storage explicit RK schemes in solving time-dependent PDEs that would result in a significant reduction in communications and relaxed synchronizations. We develop new asynchrony-tolerant schemes for ghost or buffer point updates that are necessary to maintain desired order of accuracy. The accuracy of this method is investigated, both theoretically and numerically, using simple one-dimensional linear model equations. Thereafter, we demonstrate the scalability of the proposed numerical method through three-dimensional simulations of decaying Burgers' turbulence, performed using two different asynchronous algorithms: communication-avoiding and synchronization-avoiding algorithms. The scalability studies up to 27,000 cores were found to yield speed-ups up to 6× compared to a baseline synchronous algorithm. Overall, the proposed approach shows the potential to improve the scalability of exascale PDE solvers significantly.

Parallel learning and cognitive flexibility impairments between Fmr1 knockout mice and individuals with fragile X syndrome.

Fragile X Syndrome (FXS) is a monogenic condition that leads to intellectual disability along with behavioral and learning difficulties. Among behavioral and learning difficulties, cognitive flexibility impairments are among the most commonly reported in FXS, which significantly impacts daily living. Despite the extensive use of the Fmr1 knockout (KO) mouse to understand molecular, synaptic and behavioral alterations related to FXS, there has been limited development of translational paradigms to understand cognitive flexibility that can be employed in both animal models and individuals with FXS to facilitate treatment development. To begin addressing this limitation, a parallel set of studies were carried out that investigated probabilistic reversal learning along with other behavioral and cognitive tests in individuals with FXS and Fmr1 KO mice. Fifty-five adolescents and adults with FXS (67% male) and 34 age- and sex-matched typically developing controls (62% male) completed an initial probabilistic learning training task and a probabilistic reversal learning task. In males with FXS, both initial probabilistic learning and reversal learning deficits were found. However, in females with FXS, we only observed reversal learning deficits. Reversal learning deficits related to more severe psychiatric features in females with FXS, whereas increased sensitivity to negative feedback (lose:shift errors) unexpectedly appear to be adaptive in males with FXS. Male Fmr1 KO mice exhibited both an initial probabilistic learning and reversal learning deficit compared to that of wildtype (WT) mice. Female Fmr1 KO mice were selectively impaired on probabilistic reversal learning. In a prepotent response inhibition test, both male and female Fmr1 KO mice were impaired in learning to choose a non-preferred spatial location to receive a food reward compared to that of WT mice. Neither male nor female Fmr1 KO mice exhibited a change in anxiety compared to that of WT mice. Together, our findings demonstrate strikingly similar sex-dependent learning disturbances across individuals with FXS and Fmr1 KO mice. This suggests the promise of using analogous paradigms of cognitive flexibility across species that may speed treatment development to improve lives of individuals with FXS.

Универсальный способ превентивной разгрузки судовой электроэнергетической системы

The method of preventive protection for the purposes of safe operation of the ship's electric power system in emergency situations associated with malfunctions of its elements arising during operation is considered. It is shown that existing devices form a command to unload power sources at the moment of overload, when an emergency has already occurred. At the same time, the disconnection of consumer groups occurs with a time delay. For this reason, stopping even one of the working generator sets by protection often leads to deenergization of the vessel due to overload of the remaining operational machines. A notable place in the work is given to the consideration of the method of unloading the network, in which the automatic mode is used to form a command to turn off selected electricity consumers at a time when at least one of the parallel generator sets is already inoperable, but the quality indicators of the generated electrical energy are still within acceptable limits. Within the framework of the proposed approach, the energy state of the entire ship's electric power system is predicted in the event of a decrease in its generating capacity and, if necessary, a team is formed to unload the network. The conditions under which unloading should be carried out are formulated and presented in the form of logical expressions. It is shown that the proposed approach is universal, since it does not depend on the number of generator sets operating in parallel, nor on the number of machines that have failed, nor on the type of malfunctions that have occurred. The functional diagram and description of the original device for preventive unloading of the ship's electric power system, implementing the proposed approach of preventive protection in practice, are presented.

Dynamic Parallel Flow Algorithms With Centralized Scheduling for Load Balancing in Cloud Data Center Networks

BCube is a well-known recursively defined network structure. It provides multiple low-diameter paths and good fault-tolerance for data center networks (DCNs). Its distributed routing algorithm, BCube Source Routing (BSR), can be deployed rapidly and conveniently to build multiple parallel path sets. But in the worst case, BSR may suffer from flow collisions and waste $50\%$ of the capacity of each BCube link. In this paper, to fully use those redundant links and to improve BCube load balancing, we supplement the BCube topology with a central master computer and we design two centralized dynamic parallel flow scheduling algorithms: CDPFS and CDPFSMP, for single-path and multi-path respectively. We focus on finding the least congested path for each flow by analyzing the information about the state of the global network. Furthermore, we allocate those paths to each flow in parallel. The simulation result shows that our proposed algorithms take advantage of BCube structure and deliver high-performance solutions for load balancing problems.

P&T-Inf: A Result Inference Method for Context-Sensitive Tasks in Crowdsourcing

Context-Sensitive Task (CST) is a complex task type in crowdsourcing, such as handwriting recognition, route plan, and audio transcription. The current result inference algorithms can perform well in simple crowdsourcing tasks, but cannot obtain high-quality inference results for CSTs. The conventional method to solve CSTs is to divide a CST into multiple independent simple subtasks for crowdsourcing, but this method ignores the context correlation among subtasks and reduces the quality of result inference. To solve this problem, we propose a result inference algorithm based on the Partially ordered set and Tree augmented naive Bayes Infer (P&T-Inf) for CSTs. Firstly, we screen the candidate results of context-sensitive tasks based on the partially ordered set. If there are parallel candidate sets, the conditional mutual information among subtasks containing context information in external knowledge (such as Google n-gram corpus, American Contemporary English corpus, etc.) will be calculated. Combined with the tree augmented naive (TAN) Bayes model, the maximum weighted spanning tree is used to model the dependencies among subtasks in each CST. We collect two crowdsourcing datasets of handwriting recognition tasks and audio transcription tasks from the real crowdsourcing platform. The experimental results show that our approach improves the quality of result inference in CSTs and reduces the time cost compared with the latest methods.

The StarCraft Multi-Agent Exploration Challenges: Learning Multi-Stage Tasks and Environmental Factors Without Precise Reward Functions

In this paper, we propose a novel benchmark called the StarCraft Multi-Agent Exploration Challenges(SMAC-Exp), where agents learn to perform multi-stage tasks and to use environmental factors without precise reward functions. The previous challenges (SMAC) recognized as a standard benchmark of Multi-Agent Reinforcement Learning are mainly concerned with ensuring that all agents cooperatively eliminate approaching adversaries only through fine manipulation with obvious reward functions. SMAC-Exp, on the other hand, is interested in the exploration capability of MARL algorithms to efficiently learn implicit multi-stage tasks and environmental factors as well as micro-control. This study covers both offensive and defensive scenarios. In the offensive scenarios, agents must learn to first find opponents and then eliminate them. The defensive scenarios require agents to use topographic features. For example, agents need to position themselves behind protective structures to make it harder for enemies to attack. We investigate a total twelve MARL algorithms under both sequential and parallel episode settings of SMAC-Exp and observe that recent approaches perform well in similar settings to the previous challenge, but we discover that current multi-agent approaches place relatively less emphasis on exploration perspectives. To a limited extent, we observe that an enhanced exploration method has a positive effect on SMAC-Exp, however there is still gap that state-of-art algorithms cannot resolve the most challenging scenarios of SMAC-Exp. Consequently, we propose a new axis for future research into Multi-Agent Reinforcement Learning studies.

De-storying Community Narratives: Unimagined Community in Queer Educators’ Small Stories

Background/Context: Within critical research broadly, scholars increasingly turn to stories and storytelling to pursue equity in educational contexts. Such scholarship does, however, primarily focus on the composition or creation of stories. Expanding the scope of storytelling research, this article turns to queer and trans knowledges to highlight a parallel set of storytelling practices—de-composing practices—and demonstrates their impact on historically marginalized community narratives and the pursuit of equity and justice in the field of education. Purpose/Objective/Research Question or Focus of Study: As critical calls for storying, counter-storytelling, and restorying increase within critical research in education, this article theorizes a parallel literacy practice, de-storying, as part of a set of de-composing practices. Defined as the habitual and often subconscious unimagining of community narratives in alignment with dominant narratives, de-storying shows how certain stories of marginalized communities come to be consistently unimagined. This article focuses particularly on queer community narratives and de-storying’s impact in the form of unimagined ancestors, elders, guardians, and peers. Research Design: A narrative inquiry project, this research study shares data from an inquiry community of nine queer educators. Gathering together 13 times over the course of an academic year, these educators engaged in a structured restorying process and through speculative storytelling reimagined and rewrote narrativized experiences of queerphobia. In particular, small stories demonstrated how de-storying affected these educators’ storytelling practices and, furthermore, revealed that three dominant community narratives (i.e., heteronormativity, queer fatalism, and homonormativity) compressed the potential small stories these educators told. Conclusions/Recommendations: Findings from this project illustrate how de-storying practices resulted in four unimagined community narratives across participants: missing queer ancestors, elders, guardians, and peers. De-storying occurred across various intersections of participants’ identities. Findings from this study advance critical approaches to storytelling by revealing de-storying as one of many potential de-composing practices. This article concludes by inviting the theorization of additional de-composing practices in order to center the most marginalized stories within education—namely, those that are actively unimagined.

Apatite-Graphene and Apatite-Graphene Oxide Nanocomposites: Hybrid Materials with Tailored Biological and Luminescent Properties

Apatite nanocomposites with graphene (G) or graphene oxide (GO) nanoflakes, as well as with related carbonaceous materials, present promising applications in hard tissue engineering, biomedicine, or drug delivery. Different methodologies have been explored in the last years to prepare apatite-based nanocomposites. Sitting drop vapour diffusion (SDVD) methodology induces the heterogeneous nucleation of biomimetic apatite on the reinforcement material, improving biological properties of the nanocomposites. In this work SDVD was used to prepare G-apatite and GO-apatite nanocomposites. Prior to the SDVD experiments, G flakes were obtained by sonication-assisted liquid-phase exfoliation (LPE) using L-Alanine (L-Aln) as dispersing biomolecule, while a commercial aqueous Graphene Oxide (GO) dispersion was used for the nucleation essays in presence of the same biomolecules. A parallel set of nucleation experiments was performed in presence of Tb3+ ions, to endow the nanocomposites of luminescent properties. Characterization by XRD, FTIR, and TEM demonstrated the heterogeneous nucleation of needle-shaped apatite nanocrystals on the surfaces of G and GO flakes. Fluorescence spectroscopy certified the presence of Tb3+ ions in the nanocomposites resulting in luminescent materials which can be used in imaging or theragnostic. Finally, in vitro tests with human mesenchymal stem cells revealed excellent cytocompatibility and cell proliferation in presence of the nanocomposites.

Applying behavioral studies to the ecotoxicology of corals: A case study on Acropora millepora

Behavioral responses are considered sensitive and effective indicators of organism stress. As the demand for standardized coral toxicity tests grows, innovative tools that allow for automatic and quantitative measurements of these behaviors may complement ecotoxicological studies. The rapid growth of competitive marine algae in aquaculture systems is a major issue for generating coral spat for reef restoration, and the application of non-toxic antifouling (AF) coatings might effectively mitigate this issue. While these coatings do not appear to be toxic to sensitive coral larvae, their potential to affect larval mobility has not been tested. In this context, we tested the effect of three recently-developed and potentially non-toxic AF coatings: (i) antiadhesive, (ii) cerium dioxide (CeO2-x) nanoparticle, and (iii) encapsulated biocide dichlorooctylisothiazolinone (DCOIT) on the swimming velocity and activity of Acropora millepora coral larvae for potential use in reef-restoration activities. The behavior of 32 coral larvae per AF treatment were recorded, each for 25 min, in a self-constructed dark box with two camera recording sets in parallel. The tracking analysis was performed with the software Noldus EthoVision XT. The mean larval swimming velocity on control tiles of 93.1 ± 5.6 mm min-1 (and activity of 62.8 ± 5.2%) was nearly 2-fold faster (higher) than on the antiadhesive, (CeO2-x) nanoparticle and DCOIT coatings, respectively. Larvae exposed to the DCOIT-coated tiles remained almost stationary. Although the underlying cause and consequence of these results require further investigation, tracking of coral larval swimming behavior was identified as a reliable and feasible method for assessing potential non-lethal responses to AF coatings. As changes in behavior could have significant consequences for larval survival and settlement, they are important endpoints to consider, and the quantification of behavioral responses may be a meaningful and sensitive tool. Therefore, we recommend the use of behavioral studies for coral larval assessments in ecotoxicology as a valuable endpoint. For methodological standardization and implementation, our study also features a detailed guide for video-processing and track analysis of A. millepora coral larvae in EthoVision.

Psychometric properties of the Eating in the Absence of Hunger Questionnaire in treatment-seeking adults with overweight and obesity

Understanding eating behaviors that contribute to overweight and obesity (OW/OB) is an important public health objective. One eating behavior known to contribute to overeating is eating in the absence of hunger (EAH). The Eating in the Absence of Hunger Questionnaire for Children was developed to assess external events and internal experiences that lead children to overeat. Despite the measure's adaptation for use with adults (i.e., EAH-A), its psychometric properties within this population have not been explored. This study assessed the psychometric properties of the EAH-A in sample of 311 treatment-seeking adults with OW/OB (mean BMI = 34.5 [5.1]; mean age = 46.3 [12.1]; 81.7% female; 20.6% Latinx, 59.2% white). The EAH-A contains 14 items and assesses three domains: negative affect eating (EAH-NAE), external eating, and fatigue/boredom eating, through two parallel sets of items assessing initiating EAH and continuing EAH. Exploratory Factor Analysis was performed with promax rotation and maximum likelihood factor extraction. Results supported a unitary factor of EAH, with scale responses driven by EAH-NAE items. Results may be explained in part by scale structure and domain imbalance favoring EAH-NAE items, or the true internal structure of EAH may consist of a singular latent construct. Follow-up analyses indicated redundancy of the scale's parallel sections. If researchers are primarily interested in EAH-NAE, only the three “start eating” or “keep eating” items may be needed. This study highlights the importance of validating the psychometric properties of a measure within intended populations to ensure interpretations are valid.

Trophic Position of Wintering Common Loons (Gavia immer ) in Barataria Bay, Louisiana Following the Deepwater Horizon Oil Spill

Common Loons (Gavia immer) wintering in watercourses of Barataria Bay, in coastal Louisiana were sampled in 2011–2014 following the Deepwater Horizon oil spill of 2010. Blood samples were analyzed for stable isotope ratios of carbon, nitrogen and sulfur as proxies for habitat use and diet in order to expand our understanding of the trophic position of wintering loons. The δ 13C and δ 34S values indicated that these Common Loons feed in coastal estuarine habitats. Trophic position was estimated indirectly by comparing loon stable isotope ratios with those of Brown Pelicans (Pelecanus occidentalis), a known piscivore, sampled concurrently in 2014. The isotopic signatures of the two species were not significantly different; this is consistent with the hypothesis that both species foraged primarily in coastal estuarine habitats and mainly as piscivores. No significant differences were found between subadult and adult Common Loons with respect to isotopic signatures, suggesting similar habitat usage and diet. Adults weighed more and were in better body condition than subadults. Stable isotope composition and body condition were not significantly related. Using a parallel data set of polycyclic aromatic hydrocarbons (PAH, an indicator or oil contamination) in the blood of the same loons, there was no significant relationship between PAH contamination and stable isotopic composition. Therefore, PAH-contamination could not be linked to a distinctive foraging habitat or diet.

Piazza Armerina. Les soi-disant personnifications de Mauretania et India aux extrémités du portique de la Grande Chasse

Que signifient les décors des absides du portique de la Grande Chasse ? Les personnifications au centre des deux mosaïques font-elles allusion à des entités géographiques comme cela a été proposé jusqu’à présent ? Et, dans ce cas, lesquelles ? L’analyse iconographique de chaque pavement est suivie d’un bref récapitulatif et d’une discussion des hypothèses proposées à ce jour. En nous appuyant sur un ensemble de parallèles iconographiques et textuels, nous nous efforçons de mieux cerner la signification de ces images. Nous proposons quelques pistes sur la façon dont ces mosaïques s’insèrent dans le programme décoratif du portique de la Grande Chasse auquel elles appartiennent.

Enhancing Rainfall-Runoff Simulation via Meteorological Variables and a Deep-Conceptual Learning-Based Framework

Accurate streamflow simulation is crucial for many applications, such as optimal reservoir operation and irrigation. Conceptual techniques employ physical ideas and are suitable for representing the physics of the hydrologic model, but they might fail in competition with their more advanced counterparts. In contrast, deep learning (DL) approaches provide a great computational capability for streamflow simulation, but they rely on data characteristics and the physics of the issue cannot be fully understood. To overcome these limitations, the current study provided a novel framework based on a combination of conceptual and DL techniques for enhancing the accuracy of streamflow simulation in a snow-covered basin. In this regard, the current study simulated daily streamflow in the Kalixälven river basin in northern Sweden by integrating a snow-based conceptual hydrological model (MISD) with a DL model. Daily precipitation, air temperature (average, minimum, and maximum), dew point temperature, evapotranspiration, relative humidity, sunshine duration, global solar radiation, and atmospheric pressure data were used as inputs for the DL model to examine the effect of each meteorological variable on the streamflow simulation. Results proved that adding meteorological variables to the conceptual hydrological model underframe of parallel settings can improve the accuracy of streamflow simulating by the DL model. The MISD model simulated streamflow had an MAE = 8.33 (cms), r = 0.88, and NSE = 0.77 for the validation phase. The proposed deep-conceptual learning-based framework also performed better than the standalone MISD model; the DL method had an MAE = 7.89 (cms), r = 0.90, and NSE = 0.80 for the validation phase when meteorological variables and MISD results were combined as inputs for the DL model. The integrated rainfall-runoff model proposed in this research is a new concept in rainfall-runoff modeling which can be used for accurate streamflow simulations.

Segment count and weight iny-adjective comparatives: inroads that bite off more than one can chew!

Adjectival syllable count, often used to predict English comparativesmoreversus -er, is of little help in predicting the comparatives of adjectives ending in <y>, pronounced /i/, here called they-adjectives. Examples ofy-adjectives includesillyandworthy. This article considers whether the phonemic segment count (segment count) and penultimate syllable weight (penultimate weight) ofy-adjectives may serve as alternatives to syllable count in predictingmoreversus -er. The segment count and penultimate weight of relevanty-adjective tokens from a set of diachronic corpora are studied, alongside the tokens’ morphological complexity and period of occurrence in two separate, parallel sets of mixed-effects models. Syllabification principles for penultimate weight coding differentiate the two sets of modelling. Findings converge on segment count as a predictor of the comparative form, while the role of morphological complexity remains less clear, emerging significantly from one set of modelling but not the other. A rethinking of adjectival length based on segment count is advanced for our understanding ofy-adjective comparatives. Discussed also are downstream implications of variant syllabification theories on accounts ofy-adjective comparatives, together with insights shed on morphophonological intersections and the potential place of Englishy-adjective comparatives within the ambit of English alternations.

Differentiating the Structure and Dynamics of Solute-Bound Vs. Bulk Water in Deep-Eutectic Aqueous AlCl3 Solutions

Aqueous solutions of aluminum chloride exhibit a deep eutectic (-52˚C) that is likely due to solute-directed formation of complex network structures in the solvent. It is well known that the solute-bound solvent must have a distinct chemical environment from that of the bulk solvent. Commonly used vibrational spectroscopic measurements of aqueous salt solutions are not selective enough to directly identify distinct water environments in solution. However, variable-temperature 1H-NMR spectroscopy of aqueous solutions, specifically those with high charge density salts, can distinguish water directly bound to the cation from water of the bulk solution. This unique ability to resolve characteristic water peaks by NMR spectroscopy affords the opportunity to explore the hydration structure and dynamics of deep-eutectic aqueous solutions. The aqueous AlCl3 system is an excellent model to study solution structure since we can exploit the high charge density of the ions for which strong ion-dipole interactions are structure-directing to the solvent waters, allowing resolution of distinct water chemical environments. We conducted a thorough investigation of the composition- and temperature-dependent solution structure of the AlCl3 : water system using 1H-NMR spectroscopy, and X-ray and neutron diffraction. The room-temperature proton chemical shift of water proceeds downfield with increasing salt concentration until AlCl3•22H2O, the eutectic composition, after which further increasing concentration results in an upfield chemical shift (see Figure.) Using VT-NMR, we can resolve the first-nearest neighbor water signals from the bulk signal upon cooling. 1H-NMR T1 and T2 relaxation measurement of the distinct water environments reveal stark differences in proton mobility for compositions on the water-rich versus AlCl3-rich sides of the eutectic, implying significant changes in hydration structure. To evaluate the extent to which these changes are structural, a parallel set of composition- and temperature-dependent neutron and X-ray diffraction experiments demonstrate that both cations and anions exhibit significant structure-directing influences on the solution, which we hypothesize underlies deep eutectic behavior in aqueous solutions. Figure 1

New design approach for compact evacuated tube collector/storage units

The conventional collector design procedures require extensive time and computational cost. This paper presents a systematic methodology for designing novel evacuated tube collector/storage systems (ETCS). This paper presents a novel methodology that integrates the system decomposition concept with different numerical modeling techniques to optimize the ETCS performance with minimum computational requirements. The presented methodology includes using a single evacuated tube filled with phase change material as the system building block (SBB) of the ETCS system. The enthalpy-porosity and effective heat capacity (EHC) computational fluid dynamics (CFD) methods are used to model the SBB of the novel ETCS based on the required level of details. The CFD models are used to investigate the effect of design configurations and the type of PCM on the thermal performance of the SBB. Moreover, a simplified model for the SBB is developed and used to design an efficient collector/storage unit. The results showed that the EHC model saved the computational time from 2350 min to 6 min compared to the conventional enthalpy-porosity technique with an error of <5 %. Moreover, the use of Rubitherm SP58 increased the energy storage capacity (ESC) of the SBB to 505 kJ compared 417 kJ,375 kJ, and 293 kJ for PCMs Alex 600, paraffin 54, and C22, respectively. The simplified model is used to generate a new design for the ETCS based on the optimum SBB design that uses SP58 with a glass diameter of 58 mm and length 1800 mm. The final ETCS design obtained from the design algorithm consists of four parallel sets of tubes with five tubes in each set. The paper showed the capability of the proposed methodology to design an effective and practical ETCS using minimum computational time and cost.