RESUMEN
The catalytic (SBA-15, Ni/SBA-15, Al/SBA-15 and Ni-Al/SBA-15) hydrothermal liquefaction (HTL) of rice straw biomass was examined at different temperature with different amount of catalyst in the presence of different solvents. In comparison with water solvent liquefaction, the bio-oil yield significantly increased under alcoholic solvent (ethanol and methanol). The highest bio-oil yield was observed for water (44.3â¯wt%) with Ni-Al/SBA-15, while for ethanol (56.2â¯wt%), and for methanol (48.1â¯wt%) with, Ni/SBA-15 catalyst. The loading of Ni and Al on SBA-15, the acid strength of the catalyst enhanced. Bio-oils yield were analyzed with the help of GC-MS, FT-IR, NMR, GPC and CHNS. From the GC-MS analysis, the main monomeric phenolic compounds were produced, phenol, 4-ethyl-phenol, 2-methoxy-phenol, 2-methoxy-4-ethyl-phenol and Vanillin. It was observed by CHNS and GPC analysis of the bio-oil, compared to the non-catalytic liquefaction reaction, the catalytic liquefaction reaction promotes the hydrogenation/hydrodeoxygenation and produced lower molecular weight bio-oils.
Asunto(s)
Oryza , Fenol , Biocombustibles , Biomasa , Metales , Fenoles , Espectroscopía Infrarroja por Transformada de Fourier , Temperatura , AguaRESUMEN
OBJECTIVES: The purposes of this study were to clarify (i) the prevalence of pneumoconiosis among young adults and (ii) the factors associated with pneumoconiosis among young adults to explore targeted solution for control of pneumoconiosis among young adults (aged 24-44 years). METHODS: The new cases diagnosed from 2001 to 2015 (extracted from the National Occupational Disease and Occupational Health Information Monitoring System) were involved in this research, including information of employer, patient's name, date of birth, gender, date of diagnosis, first year of dust exposure, duration of exposure, aggregation etc RESULTS: A total of 1519 pneumoconiosis cases were diagnosed among young adults (21.6% of overall cases). Silicosis was the most common type with acute process of disease. Compared with overall cases, the young patients had shorter duration of exposure, more stage II/III cases and higher aggravation rate; and were even more concentrated in small and medium enterprises where more migrant workers were employed and insufficient protective measures were used. Without further regulation, the prevalence of pneumoconiosis among young adults would bring not only disease suffering for 3000 individuals and their families, but also an annual economic loss up to 180 million yuan for Hebei province till 2025. CONCLUSIONS: As a typical heavily industrialized province of China, Hebei has severe situation on pneumoconiosis among young adults. Special attention and effort on silica-contacting industries, small and medium enterprises, and migrant workers should be focused in future occupational supervision and regulation among young adults.
Asunto(s)
Exposición Profesional/efectos adversos , Neumoconiosis/epidemiología , Adulto , Análisis de Varianza , China/epidemiología , Bases de Datos Factuales , Polvo , Femenino , Humanos , Industrias , Masculino , Neumoconiosis/diagnóstico , Prevalencia , Factores de Riesgo , Adulto JovenRESUMEN
Through first-principles calculations, we predict a new superhard carbon allotrope named C 20 - T, which possesses a cubic T symmetry with space group No.198(P213). This new carbon allotrope has an all-sp (3) hybridized bonding network with 20 atoms in its primitive unit cell. The dynamic, mechanical, and thermal stabilities of this new carbon phase at zero pressure are confirmed by using a variety of state-of-the-art theoretical calculations. Interestingly, despite the fact that C 20 - T carbon has a porous structure with large cavities, our calculations identify its superhard properties with the Vickers hardness of 72.76 Gpa. The ideal tensile and shear strength of C 20 - T carbon are calculated to be 71.1 and 55.2 GPa respectively, comparable to that of c-BN. Electronic band calculations reveal that this new carbon allotrope is a transparent insulator with an indirect band gap of 5.44 eV. These results broaden our understanding of superhard carbon allotropes.
RESUMEN
Design and synthesis of three-dimensional metallic carbons are currently one of the hot issues in contemporary condensed matter physics because of their fascinating properties. Here, based on first-principles calculations, we discover a novel stable metallic carbon allotrope (termed H18 carbon) in () symmetry with a mixed sp(2)-sp(3) hybridized bonding network. The dynamical stability of H18 carbon is verified by phonon mode analysis and molecular dynamics simulations, and its mechanical stability is analyzed by elastic constants, bulk modulus, and shear modulus. By simulating the x-ray diffraction patterns, we propose that H18 carbon would be one of the unidentified carbon phases observed in recent detonation experiments. The analysis of the band structure and density of states reveal that this new carbon phase has a metallic feature mainly due to the C atoms with sp(2) hybridization. This novel 3D metallic carbon phase is anticipated to be useful for practical applications such as electronic and mechanical devices.
RESUMEN
OBJECTIVE: To evaluate the chromium (Cr) levels in blood and urine among general population in China between 2009 and 2010, and thereby to analyze its prevalent features. METHODS: From year 2009 to 2010, a total of 11 983 subjects of general population aged between 6 and 60 year-old were recruited from 24 districts in 8 provinces in eastern, central and western China mainland, by cluster random sampling method. The information about their living environment and health status were collected by questionnaire, and 11 983 blood samples and 11 853 urine samples were also collected. Inductively coupled plasma mass spectrometry (ICP-MS) was applied to test the Cr level both in blood and urine; and the Cr distribution in blood and urine among groups of population in different ages, genders and districts, were then analyzed. RESULTS: Among general population in China, the geometric mean (GM) of Cr concentration in blood was 1.19 µg/L, with median at 1.74 µg /L and 95% percentile at 5.59 µg/L. The Cr concentration in blood among males and females were separately 1.18 µg/L and 1.20 µg/L(P > 0.05); while its GM in the groups of population aged 6 - 12, 12 - 16, 16 - 20, 20 - 30, 30 - 45 and 45 - 60 years old were 1.00, 1.22, 1.01, 1.40, 1.27 and 1.30 µg/L (P < 0.01), respectively; and the figures in populations from eastern, central and western China were 1.00, 1.70 and 1.98 µg/L (P < 0.01), respectively. Among general population, the GM of Cr concentration in urine was 0.53 µg/L, with median was lower than 0.42 µg/L and 95% percentile at 3.53 µg/L. The Cr concentration in urine among males and females were separately 0.52 µg/L and 0.53 µg/L (P > 0.05);while its GM in the groups of population aged 6 - 12, 12 - 16, 16 - 20, 20 - 30, 30 - 45 and 45 - 60 years old were 0.56, 0.60, 0.52, 0.50, 0.52 and 0.46 µg/L (P < 0.01), respectively;and the figures in populations from eastern, central and western China were 0.58, < 0.42 and 0.60 µg/L (P < 0.01), respectively. CONCLUSION: The study reported the Cr levels in blood and urine among general population in China, and thereby provided basic data evidence for the following Cr biological monitoring studies in near future.
Asunto(s)
Cromo/sangre , Cromo/orina , Vigilancia de la Población , Adolescente , Adulto , Niño , China , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
The polymeric title compound, {[Ba(2)(C(9)H(4)N(2)O(4))(2)(H(2)O)]·4.5H(2)O}(n), adopts a layer structure parallel to (001) in which adjacent Ba(II) atoms are connected by two benzimidazole-5,6-dicarboxyl-ate dianions, one functioning in a µ(4)-bridging mode and the other in a µ(5)-bridging mode. The Ba atom having water in its coordination environment as well as the Ba atom without water exist in a nine-coordinate polyhedron of O atoms; the geometry is difficult to derive. Lattice water mol-ecules occupy the space between layers and inter-act with the layers through O-Hâ¯O, O-Hâ¯N and N-Hâ¯O hydrogen bonds. ne of the five lattice water molecules is equally disordered around an inversion centre and shows half-occupancy.
RESUMEN
In the heteronuclear coordination polymer, {[CuNa(C(9)H(2)NO(8))(H(2)O)(7)]·4H(2)O}(n), the Cu(II) atom is coordinated by six O atoms from five water mol-ecules and one 5-nitro-benzene-1,2,3-tricarboxyl-ate ligand in a slightly distorted octa-hedral geometry. The Na(+) cation is surrounded by six water mol-ecules in an irregular trigonal-prismatic geometry. The Cu and Na atoms are connected by water bridges, forming an infinite chain. O-Hâ¯O hydrogen bonds involving the coordinated and uncoordinated water mol-ecules connect the chains into a three-dimensional network.
RESUMEN
In the crystal of the title compound, C(15)H(11)ClN(2)O, the molecules are linked by C-Hâ¯O and weak C-Hâ¯π inter-actions. The chloro-phenyl and phenyl rings are twisted with respect to the central pyrazolone ring, making dihedral angles of 18.23â (8) and 8.35â (8)°, respectively. The N-N and C=O bond lengths are comparable to those reported for pyrazolone compounds.