Solving games via three-valued abstraction refinement

Games that model realistic systems can have very large state-spaces, making their direct solution difficult. We present a symbolic abstraction-refinement approach to the solution of two-player games with reachability or safety goals. Given a reachability or safety property, an initial set of states, and a game representation, our approach starts by constructing a simple abstraction of the game, guided by the predicates present in the property and in the initial set. The abstraction is then refined, until it is possible to either prove, or disprove, the property over the initial states. Specifically, we evaluate the property on the abstract game in three-valued fashion, computing an over-approximation (the may states), and an under-approximation (the must states), of the states that satisfy the property. If this computation fails to yield a certain yes/no answer to the validity of the property on the initial states, our algorithm refines the abstraction by splitting uncertain abstract states (states that are may-states, but not must-states). The approach lends itself to an efficient symbolic implementation. We discuss the property required of the abstraction scheme in order to achieve convergence and termination of our technique.     

Frontal changes in the Manimahesh and Tal Glaciers in the Ravi basin,Himachal Pradesh,northwestern Himalaya (India), between 1971 and 2013

The Manimahesh and Tal Glaciers are located in the Budhil fifth-order sub-basin of the Ravi, Himachal Himalaya, Northwestern Himalaya (India). These glaciers were analysed using high- (Corona KH-4A) to medium- (Landsat TM/ETM+/OLI, ASTER) spatial resolution satellite data between 1971 and 2013, along with extensive field measurements (2011–2014) of frontal changes. The results show that the Manimahesh and Tal Glaciers retreated by 157 ± 34 m (4 ± 1 m year^–1) and 45 ± 34 m (1 ± 1 m year^–1), respectively, whereas, the total area lost is estimated at 0.21 ± 0.01 km² (0.005 km² year^–1) and 0.010 ± 0.003 km² (0.0002 km² year^–1), respectively, between 1971 and 2013. The rate of retreat is significantly lower than that previously reported. Our field measurements (2011–2014) also suggest a retreating trend and validate the measured glacier changes using remotely sensed temporal data.     

Arsenic adsorption on goethite nanoparticles produced through hydrazine sulfate assisted synthesis method

Goethite nanoparticles synthesized using hydrazine sulfate as a modifying agent were evaluated for As(V) adsorption capacity. The nanoparticles were characterized for their morphological and structural features. The precipitated goethite particles were spherical with particle size of less than 10 nm. Batch adsorption study was carried out systematically varying parameters such as pH, contact time, initial As(V) concentration and adsorbent doses. The Langmuir isotherm represented the equilibrium data well and the estimated monolayer adsorption capacity at ambient temperature was 76 mg/g, which is significantly higher than most of the adsorbents reported in the literature. Adsorption kinetic data were better represented by the pseudo-second order kinetic model. Intra-particle diffusion played a significant role in the rate controlling process in the initial hour. Desorption study showed that the loaded adsorbent could be regenerated when treated with dilute sodium hydroxide solution of pH 13.     

Electricity generation by splitting of water from hydroelectric cell: An alternative to solar cell and fuel cell

Harnessing green electricity by hydroelectric cell from water molecule splitting based on uniquely processed ferrites, multiferroic, composites and metal oxides has astonished the world. The specially processed oxygen deficient Nano porous ferrite/metal oxide attached with two dissimilar electrodes known as hydroelectric cell to generate electricity using a few drops of water for the first time it was invented in 2016. It is a primary source of energy that operates on the principle of spontaneous water molecule dissociation (OH⁻ and H₃O⁺) by oxygen deficient and Nano porous materials such as Mg_0.8Li_0.2Fe₂O₄, SiO₂, SnO₂, MgO, Fe₂O₃, Fe₃O₄, and TiO₂. The electrodes attached on oxide pellets are the Zn sheet anode and inert cathode Ag paste fabricated as hydroelectric cell. Chemi-dissociation of water molecule on the pellet surface followed by physi-dissociation results into H₃O⁺ ion hopping and that ultimately leads to hopping of H⁺ ions into nanopores. This phenomenon generates enough electric potential that spontaneously dissociates physisorbed water molecules on the pellet surface, thus sustaining current in the cell. Redox reactions of OH⁻ and H₃O⁺ at Zn and Ag electrodes, respectively, generate cell potential, which allows the flow of electric current in the external circuit of the cell. A pellet of size 1 in. square of Mg_0.8Li_0.2Fe₂O₄, SnO₂, and Fe₃O₄ etc. is able to deliver current of 8, 22, and 50 mA with a voltage of 0.98, 0.78, and 0.83 V, respectively. Hydroelectric cell working in different functional mode is able to produce high purity hydrogen gas and zinc hydroxide nanoparticles also. This review compiled the detailed working mechanism of recently invented hydroelectric cell, with studies done on different oxide materials in order to understand their water splitting properties, its advantages and limitation along with future prospect for complementing other sources for power generation. Hydroelectric cell has brought a big revolution recently in green energy sector by opening a new field in energy materials based on water splitting by non-photocatalytic process and is progressing rapidly its development, therefore there is a need of concise and comprehensive article to introduce its working to advance this new green energy device knowledge to young researchers globally. Conduciveeconomics, ubiquitous resources, user friendly technology with no disposal issue make hydroelectric cell a future potential green energy source as a better low cost alternative to solar and fuel cell.     

Inadvertently high dialysate magnesium causing weakness and nausea in hemodialysis patients

As maintenance hemodialysis patients are exposed to large quantities of dialysis water, any contamination of it might be reflected in plasma levels. We present a series of cases due to such a contamination. Six maintenance hemodialysis patients dialyzing at the same peripheral hemodialysis facility presented to us over a short period of time with symptoms mimicking inadequate dialysis. Their blood urea and creatinine levels were not very high, but all the patients had hypermagnesemia [serum Mg levels = 1.8 (±0.3) mmol/L]. Except for one patient who had cardiac arrest at presentation, all patients improved after undergoing hemodialysis at our center [serum Mg at discharge = 0.86 (±0.01) mmol/L]. The origin of hypermagnesemia was traced to dialysis water contamination with magnesium due to inadequate maintenance of the water treatment system. Corrective measures improved the quality of water, and no further cases were reported from that center. Proper maintenance and periodic checks of the quality of water are central to the outcomes of maintenance hemodialysis patients.     

Modeling an Augmented Lagrangian for Blackbox Constrained Optimization

Constrained blackbox optimization is a difficult problem, with most approaches coming from the mathematical programming literature. The statistical literature is sparse, especially in addressing problems with nontrivial constraints. This situation is unfortunate because statistical methods have many attractive properties: global scope, handling noisy objectives, sensitivity analysis, and so forth. To narrow that gap, we propose a combination of response surface modeling, expected improvement, and the augmented Lagrangian numerical optimization framework. This hybrid approach allows the statistical model to think globally and the augmented Lagrangian to act locally. We focus on problems where the constraints are the primary bottleneck, requiring expensive simulation to evaluate and substantial modeling effort to map out. In that context, our hybridization presents a simple yet effective solution that allows existing objective-oriented statistical approaches, like those based on Gaussian process surrogates and expected improvement heuristics, to be applied to the constrained setting with minor modification. This work is motivated by a challenging, real-data benchmark problem from hydrology where, even with a simple linear objective function, learning a nontrivial valid region complicates the search for a global minimum. Supplementary materials for this article are available online.     

Recent developments in the application of microwave energy in process metallurgy at KUST

Kunming University of Science and Technology (KUST) has successfully developed, designed, fabricated and installed industrial microwave units for (i) removal of halides, (ii) activation of carbon, (iii) heating of dust laden air in electrostatic precipitators, (iv) drying of water based paints, and (v) heating of the HF pickling solution for cold rolled titanium alloy coils. This review article provides a summary of these process metallurgy applications. It is found that the use of microwave energy can increase the process efficiency, giving advantages, such as lower reaction temperature and shorter reaction time compared to traditional processes.

可显著降低反应温度、缩短时间,具有强化作用     

Polydivinylferrocene surface modified electrode for measuring state-of-charge of lead–acid battery

This paper outlines an investigation of the electrochemical behaviour of polymeric divinylferrocene (PDVF) produced by direct polymerisation of divinylferrocene (DVF) monomer on a glassy carbon substrate. The findings indicate that PDVF undergoes reversible reduction/oxidation in neutral and acidic aqueous media containing perchlorate (ClO₄⁻) and sulfhate (SO₄²⁻). The anodic peak potential of the PDVF shifts linearly to less positive potentials as the sulfuric acid (H₂SO₄) concentration is increased from 1 to 5 M. The polymer film strongly adheres to the glassy carbon surface and is electrochemically stable when subjected to repeated voltammetric cycling in the potential range of −0.2 to +0.8 V vs. Ag|AgCl. The potential of the partially oxidized film of PVDF on a glassy carbon substrate against a Ag|AgCl/KCl reference electrode in sulfuric acid solution is stable, reproducible and varies linearly with the acid concentration in the range of 1–5 M. This observation may be suitable for potentiometrically measuring the state-of-charge of lead–acid batteries.     

Extraction of High-Value Chemicals from Plants for Technical and Medical Applications

Plants produce a variety of high-value chemicals (e.g., secondary metabolites) which have a plethora of biological activities, which may be utilised in many facets of industry (e.g., agrisciences, cosmetics, drugs, neutraceuticals, household products, etc.). Exposure to various different environments, as well as their treatment (e.g., exposure to chemicals), can influence the chemical makeup of these plants and, in turn, which chemicals will be prevalent within them. Essential oils (EOs) usually have complex compositions (>300 organic compounds, e.g., alkaloids, flavonoids, phenolic acids, saponins and terpenes) and are obtained from botanically defined plant raw materials by dry/steam distillation or a suitable mechanical process (without heating). In certain cases, an antioxidant may be added to the EO (EOs are produced by more than 17,500 species of plants, but only ca. 250 EOs are commercially available). The interesting bioactivity of the chemicals produced by plants renders them high in value, motivating investment in their production, extraction and analysis. Traditional methods for effectively extracting plant-derived biomolecules include cold pressing and hydro/steam distillation; newer methods include solvent/Soxhlet extractions and sustainable processes that reduce waste, decrease processing times and deliver competitive yields, examples of which include microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), subcritical water extraction (SWE) and supercritical CO₂ extraction (scCO₂). Once extracted, analytical techniques such as chromatography and mass spectrometry may be used to analyse the contents of the high-value extracts within a given feedstock. The bioactive components, which can be used in a variety of formulations and products (e.g., displaying anti-aging, antibacterial, anticancer, anti-depressive, antifungal, anti-inflammatory, antioxidant, antiparasitic, antiviral and anti-stress properties), are biorenewable high-value chemicals.