Three Li- and Mg-cosubstituted compounds in the Gd5-x(Li/Mg)xGe4 (x = 1.04(2), 1.17(2), 1.53(2)) system have been successfully prepared by conventional high-temperature reactions. According to powder and single-crystal X-ray diffraction analyses, all three compounds adopt a Gd5Si4-type phase with the orthorhombic Pnma space group (Pearson code oP16, Z = 4) and six crystallographically independent atomic sites. The crystal structure can be described as a combination of two-dimensional Mo2FeB2-type ∞2[Gd2(Li/Mg)Ge2] layers and [Ge2] dimers. Interestingly, as 64% of Li and 26% of Gd at the RE3 and RE2 sites, respectively, were exclusively substituted by Mg in Gd3.47(1)Li0.36(2)Mg1.17(3)Ge4, the lattice parameter b was selectively shortened as a result of the RE3-Ge1 bond shrinkage in comparison to that in Gd4LiGe4, while lattice parameters a and c remained nearly intact. A series of theoretical calculations using the tight-binding linear muffin-tin orbital (TB-LMTO) method indicated that the reduction of the particular RE3-Ge1 bond distance in the title compounds could also be explained by an optimization of bonding based on the corresponding RE3-Ge1 crystal orbital Hamilton population (COHP) curve. Moreover, the specific site preference of Mg for the RE3 site was supported by both size-factor as well as electronic-factor criteria on the basis of the smallest atomic size and the highest electronegativity of Mg among the three cations. Therefore, the overall electronic structure was further interrogated by a density of states (DOS) analysis. The influence of nonmagnetic Li/Mg cosubstitution for the magnetic Gd atoms in the title Gd5-x(Li/Mg)xGe4 system on the magnetic characteristics was also thoroughly studied by isofield magnetization at 100 Oe and 10 kOe and isothermal magnetization measurements at 4 K using two of the title compounds: Gd3.83(1)Li0.48Mg0.69(3)Ge4 and Gd3.47(1)Li0.36(2)Mg1.17(3)Ge4.

Three Zintl phase compounds belonging to the CaYb4Al2Sb6-xGex(x = 0.2, 0.5, 0.7; nominal compositions) system with various Ge-doping contents were successfully synthesized by arc-melting and were initially crystallized in the Ba5Al2Bi6 -type phase (space group Pbam, Pearson codes oP26). However, after post-heat treatment at an elevated temperature, the originally obtained crystal structure was transformed into the homeotypic Ca5Ga2Sb6 -type structure according to powder and single-crystal X-ray diffraction analyses. Two types of crystal structures share some isotypic structural moieties, such as the one-dimensional anionic chains formed by L[Al2Sb8] and the void-filling Ca-2(+)/Yb2+ mixed cations, but the slightly different spatial arrangements in each unit cell make these two structural types distinguishable. This series of title compounds is originally investigated to examine whether anionic p-type doping using Ge can successfully enhance thermoelectric (TE) properties of the Yb-rich CaYb4Al2Sb6-xGex series even after the phase transition from the Ba5Al2Bi6 -type to the Ca5Ga2Sb6 -type phase. More interestingly, we also reveal that the given structural transformation is triggered by the particularly different site-preference of Ca2+ and Yb2+ among three available cationic sites in each structure type, which is significantly affected by thermodynamic conditions of this system. Band structure and density of states analyses calculated by density functional theory using the tight-binding linear muffin-tin orbital method also prove that the Ge-doping actually increases band degeneracies and the number of resonant peaks near the Fermi level resulting in the improvement of Seebeck coefficients. Electron localization function analyses for the (0 1 0) sliced-plane and the 3D isosurface nicely illustrates the distortion of the paired-electron densities due to the introduction of Ge. The systematic TE property measurements imply that the attempted anionic p-type doping is indeed effective to improve the TE characteristics of the title CaYb4Al2Sb6-yGey system.

Climate change is considered to be a potential cause of global warming, which leads to a continuous rise in the global atmospheric temperature. This rising temperature also alters precipitation conditions and patterns, thereby causing frequent occurrences of extreme calamity, particularly droughts and floods. Much evidence has been documented by the Intergovernmental Panel on Climate Change, illustrating fluctuations in precipitation patterns caused by global climate change. Recent studies have also highlighted the adverse impact of climate change on river flow, groundwater recovery, and flora and fauna. The theoretical political approach and scientific progress have generated ample opportunities to employ previously allusive methods against impacts caused by varying climatic parameters. In this study, the current state of India’s water environment policy is compared with that of South Korea. The “3Is”—ideas, institutions, and interests—which are considered pillars in the international field of political science, are used as variables. The concept of “ideas” highlights the degree of awareness regarding climate change while formulating water environment policy. Here, the awareness of India’s management regarding emerging water issues related to climate change are discussed and compared with that of South Korea. The concept of “institutions” illustrates the key differences in water environment policy under the umbrella of climate change between both countries within the associated national administrations. India’s administrations, such as the Ministry of Environment, Forests, and Climate Change; the Ministry of Water Resources, River Development, and Ganga Rejuvenation; the Ministry of Rural Development; and the Ministry of Housing and Urban Affairs, are used as a case study in this work. Finally, the concept of “interest” elaborates the prioritization of key issues in the respective water environment policies. Common interests and voids in the policies of both countries are also briefly discussed. A comparison of India’s water environment policies with that of South Korea is made to expose the gaps in India’s policies with respect to climate change, thereby seeking to identify a solution and the optimal direction for the future of the water environment policy of India.

Continuous dumping of oyster shells in open fields has been a global issue, causing serious problems in the water and human health. The conversion of those wastes into value-added products is highly desirable. Here, Green Calcium Hydroxide Nano-plates (GCHNPs) were first synthesized from waste oyster shells by a chemical precipitation method in an aqueous medium at 90 °C without using any additives. The crystal structure with a hexagonal portlandite (Ca(OH)2) was observed by both X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The crystal size of around 350-450 nm and specific surface area with 4.96 m2g-1 were confirmed by field emission scanning electron microscopy (FE-SEM) and Brunauer-Emmett-Teller (BET), respectively. In addition, a schematically organized new qualitative model for a mechanism was proposed to explain the genesis and evolution of GCHNPs from raw oyster shells.

Global warming affects water supply and water resources throughout the world. In many countries, climate change affects significantly on the fresh water resources. Vietnam is exposed mainly, to landslides and floods triggered by tropical storms and monsoon rains, although storm surge, whirlwind, river bank and coastal line erosion, hail rain. In addition to the prevalent drought, there are many major water challenges, including water availability, stress, scarcity and accessibility, because of poor resource management. Fast growth of urbanization, industrialization and population growth, agricultural activities and climate change cause heavy pressure on water quality. Both domestic and industrial wastewater, as well as storm water shares the same drainage. The common facilities for wastewater treatment are not available. Therefore, wastewater is treated only superficially and then discharged directly into rivers and lakes causing serious pollution of surface water environment. In this paper, we reported the severe water crisis and massive green algal blooms formation in Vietnam rivers and lakes. This is the biggest evidence of climate change variations in Vietnam.

The solid-solution Zintl compounds with the mixed cations of Ca2+ and Yb2+ in the Ca5-xYbxAl2Sb6 (1.0 <= x <= 5.0) system have been synthesized by high-temperature solid-state reactions. Two slightly different crystal structures of the Ba5Al2Bi6-type and Ca5Ga2Sb6-type phases have been characterized for seven compounds with 2.5 <= x <= 5.0 and three compounds with 1.0 <= x <= 2.0, respectively, by both powder and single-crystal X-ray diffraction analyses. The two title phases adopt the orthorhombic space group Pbam (Z = 2, oP26) with seven independent asymmetric atomic sites and share certain structural similarities, including infinite one-dimensional [Al2Sb8] double chains and isolated space-filling Ca2+/Yb2+ cations. Interestingly, we reveal the crystal-to-crystal solid-state structural transformation of the Yb-rich compound Ca1.5Yb3.5Al2Sb6 from the Ba5Al2Bi6-type to the Ca5Ga2Sb6-type phase through the postannealing process, which can be rationalized as the phase transition from the kinetically more stable structure to the thermodynamically more stable crystal structure on the basis of theoretical calculations. Discrepancies of the local coordination geometries of the anionic [Al2Sb8] units and the geometrical arrangements of structural building moieties in the two distinct phases provoke the different electrical properties of metallic and semiconducting conduction, respectively, for the Ba5Al2Bi6-type and Ca5Ga2Sb6-type phases. Density of states and crystal orbital Hamilton population analyses based on tight-binding linear muffin-tin orbital calculations prove that the band-gap opening in the Ca5Ga2Sb6-type phase should mainly be attributed to an extended bond distance of the bridging Sb-Sb in the [Al2Sb8] unit. A series of thermoelectric (TE) property measurements indicates that the phase transition via the postannealing process eventually results in an enhancement of the TE performance of Yb-rich Ca1.5Yb3.5Al2Sb6.

Arsenic contamination of water is a worldwide issue due to its severe effects on the human body. Coffee grounds are a porous material with network structures, making it absorb other substances such as some gases or elements. In this research, renewable coffee wastes were used as an adsorbent to extract arsenic (As) from wastewater. In order to evaluate the usefulness of untreated coffee grounds, a series of preliminary tests for attachment of arsenic to coffee grounds were provided. The Brunauer–Emmett–Teller (BET) surface area and adsorption–desorption isotherms of an untreated coffee ground obtained from N2 gas adsorption were provided, and pore sizes was obtained using Barrett–Joyner–Halenda (BJH) method. The adsorption capacities of the coffee waste were verified through a series of experimental processes changing the conditions such as concentration of arsenic, initial amount of coffee grounds, and pH. The maximum absorption concentration of 6.44 mg/L on 1 g of coffee grounds at 1.00 mM of arsenic solution was observed. It was demonstrated that the modification by the cation species or pretreatment processes, such as calcination, will be necessary to enhance the absorption capacity for the extraction of arsenic.

Alkaline flocculation has been considered as a potential candidate to remove algae and eutrophic substances from water. A number of researches using low-cost and environmentally friendly methods have been suggested to optimize removal efficiency. In this study, a calcium-containing waste oyster shell, as an environmentally friendly substance, has been used to treat phosphorous, a eutrophic substance, and to remove algae from the fresh water simultaneously. The X-ray Fluorescence (XRF) analysis showed that CaO was a major phase in a raw oyster shell, which played an important role for flocculation of phosphorous as well as algae. In order to eliminate the algae or phosphorous effectively, oyster shell was calcined at 1000 °C and hydrated in water. The slurry of hydrated calcined oyster shell, from 5 g/L to 12.5 g/L, was utilized in this experiment, where the experimental results were compared with that of dolomite. A series of experimental investigations, such as pH and turbidity changes using the water quality analyzer and UV-Visible spectroscopy (UV-Vis), demonstrated that the algae were efficiently removed. In addition, total phosphorous (TP) and total nitrogen (TN) analyses at different amounts of slurries of the hydrated calcined oyster shell showed that almost all the phosphorous was removed at 7.5 g/L of hydrated oyster shell, but due to the high solubility of nitrogen compounds, no obvious effect for the removal of nitrogen was observed. Furthermore, powder X-ray diffractions (PXRD) showed that Ca(OH)2 compounds were transformed to the phosphate compound, suggesting that the oyster shell caused flocculation by chemically forming with phosphorous ions.

In this work, we present a detailed study on the magnetic property and critical behavior in the austenitic phase of Ni43Mn46Sn8X3 alloys with X=Cr and In, which were prepared by an arc-melting method in an argon ambience. The M(T) curve of the Cr sample (X=Cr) exhibits a single magnetic phase transition at the Curie temperature of the ferromagnetic (FM) austenitic phase with TAC=303K. In contrast, the In sample (X=In) exhibits multiple magnetic phase transitions, including a magnetic phase transition from a FM state to weakly magnetic state at TMC=165K of the martensitic phase, a martensitic transition from the weakly magnetic to the FM austenite phase at TM-A=259K, and a magnetic phase transition from the FM to paramagnetic (PM) at TAC=297K of the austenite phase. Based on the Landau theory and M(H) data measured at different temperatures, we pointed that the FM-PM phase transitions around TAC in both samples were the second-order phase transition. Our results suggest an existence of the long-range FM interactions in the austenite phase. A small deviation from the mean-field theory of the critical exponents has been also observed pointing out an existence of the inhomogeneous magnetism that could be associated with the presence of the anti-FM interactions in these samples. Besides, their effective exponents βeff(ε) and γeff(ε) have been also calculated.

The Zintl phase solid-solution Ca11-xYbxSb10-yGez (0 ≤ x ≤ 9; 0 ≤ y ≤ 3; 0 ≤ z ≤ 3) system with the cationic/anionic multisubstitution has been synthesized by molten Sn metal flux and arc-melting methods. The crystal structure of the nine title compounds were characterized by both powder and single-crystal X-ray diffractions and adopted the Ho11Ge10-type structure with the tetragonal space group I4/mmm (Z = 4, Pearson Code tI84). The overall isotypic structure of the nine title compounds can be illustrated as an assembly of three different types of cationic polyhedra sharing faces with their neighboring polyhedra and the three-dimensional cage-shaped anionic frameworks consisting of the dumbbell-shaped Sb2 units and the square-shaped Sb4 or (Sb/Ge)4 units. During the multisubstitution trials, interestingly, we observed a metal-to-semiconductor transition as the Ca and Ge contents increased in the title system from Yb11Sb10 to Ca9Yb2Sb7Ge3 (nominal compositions) on the basis of a series of thermoelectric property measurements. This phenomenon can be elucidated by the suppression of a bipolar conduction of holes and electrons via an extra hole-carrier doping. The tight-binding linear muffin-tin orbital calculations using four hypothetical structural models nicely proved that the size of a pseudogap and the magnitude of the density of states at the Fermi level are significantly influenced by substituting elements as well as their atomic sites in a unit cell. The observed particular cationic/anionic site preferences, the historically known abnormalities of atomic displacement parameters, and the occupation deficiencies of particular atomic sites are further rationalized by the QVAL value criterion on the basis of the theoretical calculations. The results of SEM, EDS, and TGA analyses are also provided.

A novel intermetallic compound of Ce11Ge3.73(2)In6.27 has been synthesized through the high-temperature solid-state reaction using Nb-ampoules. A batch of well grown block-/short bar-shaped single-crystals has been obtained, and the crystal structure of the title compound has been characterized by single-crystal X-ray diffraction analyses. Ce11Ge3.73(2)In6.27 adopts the Ho11Ge10-type structure belonging to the tetragonal space group I4/mmm (Z=4, Pearson symbol tI84) with nine crystallographically unique atomic positions in the asymmetric unit. The lattice parameters are a=12.0163(1) Å and c=16.5396(2) Å. The overall crystal structure can simply be depicted as an assembly of three different types of co-facial cationic polyhedra centered by anions, which is further enclosed by the three-dimensional (3-D) cage-like anionic framework. The extra amount of In is observed in one of three isolated anionic sites resulting in introducing the Ge/In-mixed site at the Wyckoff 4e site. This unique site-preference of In substitution for Ge at the 4e site has been enlightened via the atomic size-aspect which was fully supported and rationalized by the site- and bond-energies analyses using tight-binding linear muffin-tin orbital (TB-LMTO) calculations. Energy-dispersive X-ray spectroscopy (EDS), density of states (DOS), crystal orbital Hamilton population (COHP), and electron localization function (ELF) analyses for the title compound are also presented. Magnetic susceptibility measurement proves that an antiferromagnetic ordering of Ce atoms at a low temperature with a paramagnetic Curie temperature of −23.2 K.

Four quaternary Zintl phases with mixed-cations in the Yb14-xCaxAlSb11 (4.81 ≤ x ≤ 10.57) series have been synthesized by using the arc-melting and the Sn metal-flux reaction methods, and the isotypic crystal structures of the title compounds have been characterized by both powder and single-crystal X-ray diffraction (PXRD and SXRD) analyses. The overall crystal structure adopting the Ca14AlSb11-type can be described as a pack of four different types of the spiral-shaped one-dimensional octahedra chains with various turning radii, each of which is formed by the distorted ((Yb/Ca)Sb6) octahedra. Four symmetrically-independent cationic sites contain mixed occupations of Yb2+ and Ca2+ with different mixing ratios and display a particular site preference by two cationic elements. Two hypothetical structural models of Yb4Ca10AlSb11 with different cationic arrangements were designed and exploited to study the details of site and bond energies. QVAL values provided the rationale for the observed site preference based on the electronegativity of each atom. Density of states (DOS) curves indicated a semiconducting property of the title compounds, and crystal orbital Hamilton population (COHP) plots explained individual chemical bonding between components. Thermal conductivity measurement was performed for Yb8.42(4)Ca5.58AlSb11, and the result was compared to compounds without mixed cations.

A meticulously designed, polar, non-centrosymmetric lead borate chloride, Pb2 BO3 Cl, was synthesized using KBe2 BO3 F2 (KBBF) as a model. Single-crystal X-ray diffraction revealed that the structure of Pb2 BO3 Cl consists of cationic [Pb2 (BO3 )](+) honeycomb layers and Cl(-) anions. Powder second harmonic generation (SHG) measurements on graded polycrystalline Pb2 BO3 Cl indicated that the title compound is phase-matchable (type I) and exhibits a remarkably strong SHG response, which is approximately nine times stronger than that of potassium dihydrogen phosphate, and the largest efficiency observed in materials with structures similar to KBBF. Further characterization suggested that the compound melts congruently at high temperature and has a wide transparency window from the near-UV to the mid-IR region.

Two novel polar intermetallic compounds have been synthesized by a high‐temperature reaction method, and their crystal structures have been characterized by both single‐crystal and powder X‐ray diffractions. La15Ge9Li1 .50(16) crystallizes in the hexagonal space group P63 mc (Z = 2, Pearson code hP52) with nine crystallographically independent sites in the unit cell, and the lattice parameters are a = 15.516(2) and c = 6.895(2) Å. The overall crystal structure can be described as a √3 × √3 × 1 superstructure of the parent compound La5Ge3 adopting the Mn5Si3‐type, and such a superstructure transformation should be attributed to the particular ordering patterns of interstitial Li atoms at the Wyckoff 2a and 2b sites with different occupation factors. La7Ge3 also crystallizes in the hexagonal P63 mc space group (Z = 2, Pearson code hP20) with three La and one Ge non‐equivalent sites in the unit cell. The lattice parameters are a = 10.666(1) and c = 6.357(1) Å. The crystal structure of La7Ge3 shares some similarities with La15Ge9Li1.50(16) and its parent compound La5Ge3, such as the one‐dimensional (1D) zigzag confacial La6 octahedra chains and the 1D zigzag La atomic chains. Theoretical investigations using tight‐binding linear muffin‐tin orbital (LMTO) method provide a comprehensive understanding about electronic structures and chemical bonding of two title compounds based upon density of states (DOS) and crystal orbital Hamilton population (COHP) analyses. The solid‐state 7Li NMR spectrum measurement proves the existence of two independent interstitial Li positions at two distinctive octahedral sites in La15Ge9Li1.50(16).

Single crystals of Pb 2 BO 3 Cl are grown from a 3:1:2 molar mixture of PbO, PbCl 2 and H 3 BO 3 (evacuated silica tubes, 720 °C, 24 h; cooling to 650 °C at a rate of 3 °C/h).

Small single crystals of La 15 Ge 9 Li 1.50 (I) and La 7 Ge 3 (II) are obtained by solid state reaction of a 15:9:2 (7:3) molar mixture of the elements (Nb ampoule in evacuated silica tubes, 1080 °C, 5 h).

A systematic study of the conventional and inverse magnetocaloric effects, and critical behaviors in an alloy ingot of Ni43Mn46Sn8In3 has been performed. Our results reveal the sample exhibiting structural and magnetic phase transitions at temperatures T-C(M) = 166 K (T-C of the martensitic phase), T-M (A) = 260 K (the martensitic-to-austenitic phase transformation) and T-C(A) = 296 K (T-C of the austenitic phase). The large values of refrigerant capacity (RC) around TM-A and T-C(A) are found to be RCM-A = 172.6 and RCA = 155.9 J kg(-1), respectively, under an applied field change of 30 kOe. Our critical analyses near the T-C(M) and TC A reveal that a coexistence of the long-and short-range ferromagnetic order in the martensitic phase, while the long-range ferromagnetic order exists in the austenitic phase. Interestingly, at around TC A, the maximum magnetic entropy change (vertical bar Delta S-max vertical bar) versus magnetic field H obeys a power law, vertical bar Delta S-max vertical bar = a.H-n, where the exponent n is found to be about 0.66. (C) 2015 Elsevier B.V. All rights reserved.

The remarkably large SHG efficiency of KCdCO3F originates from enhancement via interatomic interactions between the s and p states of Cd2+ and the π-conjugated groups of the [CO3]2− unit.

LaLi0.92Cu1.33P2, PrLi0.98Cu1.54P2, NdLi0.91Cu1.42P2, GdLiCu1.48P2, and ErLi0.82Cu1.19P2 are synthesized from the elements (Nb ampule, 1100 °C, 10 h).