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101.
102.
The development of new biopolymer electrolytes (BEs) based on carboxy methylcellulose (CMC) has been accomplished by incorporating dodecyltrimethyl ammonium bromide (DTAB) to the polymer–salt system via solution-cast technique. The polymer–salt complex formation and the polymer–proton interactions have been analyzed through Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) measurement, impedance measurement and Transference number measurement (TNM). The highest conductivity at room temperature is 7.72 × 10? 4 Scm? 1 for sample containing 35 wt. % DTAB. The temperature dependence of the BEs system exhibits Arrhenius behavior. The conductivity of the samples was found to be dependent on the number of mobile ions and the mobility of the ions. It has been shown that the conducting species in this present work are predominantly due to proton (H+) which was confirmed via FTIR and TNM analysis. The results suggest that BEs system is highly potential to be applied in electrochemical devices, i.e. proton battery and fuel cell. 相似文献
103.
Olumegbon Ismail Adewale Alade Ibrahim Olanrewaju Sahaluddin Mirza Oyedeji Mojeed Opeyemi Sa’ad Aliyu Umar 《Journal of Thermal Analysis and Calorimetry》2021,145(4):1769-1777
Journal of Thermal Analysis and Calorimetry - The viscosity of a nanofluid is one of its fundamental thermophysical properties, and it is an important consideration in heat transfer applications.... 相似文献
104.
Abubakar Sadiq Aliyu Umar Ibrahim Chidozie Timothy Akpa Nuraddeen Nasiru Garba Ahmad Termizi Ramli 《Isotopes in environmental and health studies》2013,49(3):448-468
Nasarawa State is located in north central Nigeria and it is known as Nigeria's home of solid minerals. It is endowed with barite, copper, zinc, tantalite and granite. Continuous releases of mining waste and tailings into the biosphere may result in a build-up of radionuclides in air, water and soil. This work therefore aims to measure the activity concentration levels of primordial radionuclides in the soil/sediment samples collected from selected mines of the mining areas of Nasarawa State. The paper also assesses the radiological and radio ecological impacts of mining activities on the residents of mining areas and their environment. The activity concentrations of primordial radionuclides (226Ra, 232Th and 40K) in the surface soils/sediment samples were determined using sodium iodide-thallium gamma spectroscopy. Seven major mines were considered with 21 samples taken from each of the mines for radiochemistry analysis. The human health hazard assessment was conducted using regulatory methodologies set by the United Nations Scientific Committee on the Effects of Atomic Radiation, while the radio ecological impact assessment was conducted using the ERICA tool v. 1.2. The result shows that the activity concentrations of 40K in the water ways of the Akiri copper and the Azara barite mines are 60 and 67?% higher than the world average value for 40K, respectively. In all mines, the annual effective dose rates (mSv y?1) were less than unity, and a maximum annual gonadal dose of 0.58 mSv y?1 is received at the Akiri copper mine, which is almost twice the world average value for gonadal dose. The external hazard indices for all the mines were less than unity. Our results also show that mollusc-gastropod, insect larvae, mollusc-bivalve and zooplankton are the freshwater biotas with the highest dose rates ranging from 5 to 7 µGy h?1. These higher dose rates could be associated with zinc and copper mining at Abuni and Akiri, respectively. The most exposed terrestrial reference organisms are lichen and bryophytes. In all cases, the radio ecological risks are not likely to be discernible. This paper presents a pioneer data for ecological risk from ionizing contaminants due to mining activity in Nasarawa State, Nigeria. Its methodology could be adopted for future work on radioecology of mining. 相似文献
105.
The rationale for selection of waste cellulose source and method for its degradation, such as ultrasound, aeration and coupled energy, is examined. Consideration is given to the availability of waste material for the conservation of global resources, pollution effects from energy forms and efficiency of energy transfer. Availability of the sources and possible ways of converting them to fuels, processes involved in its production and the possible effects on the environment are discussed. Manufactured cellulose and waste paper are used as the source for these experiments and the rationale behind their use in the environment is analysed. An ultrasound reactor that operates at 80 W and 38 kHz was used in breaking down the samples to produce glucose and other chemical species. One of the routes being explored is the further conversion of these molecules into fuel (alcohol). 相似文献
106.
Gülseven Sıdır Y Sıdır I Taşal E Ermiş E 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(2):640-647
The electronic absorption spectra of a series of azo dye compounds containing -Cl, -SO3H and -OH groups were recorded in twenty one solvents with different polarities. The solvents were selected to cover a wide range of parameters (refractive index, dielectric constant and hydrogen bonding ability). Solvent-induced effect on the maximum absorption band frequencies of azo dye compounds are described in terms of solute-solvent interactions. Multiple linear regression equation for νmax was performed using polarizability-polarity parameters and Kamlet-Taft solvatochromic parameters. The results help to assign the solvent-solute interactions and the solvatochromic potential of the investigated compounds. It is concluded that the electronic of the substituent and hydrogen bonding acceptor ability of the solvents are the major factors to the interaction in solutions. 相似文献
107.
We consider an implicit iterative process for two finite families of mappings in a real Banach space and prove strong convergence results without using the Lipschitz condition on mappings. Our results mainly improve and extend the recent results of Chang et al. (2001, 2009, 2007) [1], [2], [3], Cho et al. (2005) [4], Gu (2008) [14], Ofoedu (2006) [9], Schu (1991) [13], Zeng (2003, 2005) [20], [21], and Qin et al. (2008) [11], [12]. 相似文献
108.
Isa Ruppen Canás Keith O’Callaghan Cian Moroney Brett Hamilton Kevin J. James Ambrose Furey 《Analytical and bioanalytical chemistry》2010,398(3):1477-1491
The azaspiracids are a family of lipophilic polyether marine biotoxins that have caused a number of human intoxication incidents
in Europe since 1995 after consumption of contaminated shellfish (Mytilus edulis). Levels of azaspiracids in shellfish for human consumption are monitored in accordance with EU guidelines: only shellfish
with less than 160 μg kg−1 are deemed safe. The limited availability of commercially available standards for azaspiracids is a serious problem, because
validated LC–MS methods are required for routine analysis of these toxins in shellfish tissues. The procedure described herein
has been used for the separation and the isolation of four azaspiracid (AZA) toxins from shellfish, for use as LC–MS–MS reference
materials. Five separation steps have been used to isolate azaspiracids 1, 2, 3, and 6. The purity of the toxins obtained
has been confirmed by multiple mass spectrometric methods using authentic azaspiracid standards. The same techniques have
been used for quantification of the toxins extracted. The isolation procedure involves several chromatographic purification
techniques: solid-phase extraction (diol sorbent, 90% mass reduction, and 95 ± 1% toxin recovery); Sephadex size-exclusion
chromatography (87% mass reduction and up to 95 ± 2% toxin recovery), Toyopearl HW size-exclusion chromatography (90% mass
reduction and up to 92.5 ± 2.5% toxin recovery), and semi-preparative LC (78 ± 3% toxin recovery). The procedure effectively
separates the toxins from the sample matrix and furnishes azaspiracid toxins (AZA1, AZA2, AZA3 and AZA6) of sufficient purity
with an average yield of 65% (n = 5). Triple-quadrupole mass spectrometry was used for qualitative and quantitative monitoring of the isolation efficiency
after each stage of the process. High-resolution mass spectrometric evaluation of the toxic isolated material in both positive
and negative modes suggests high purity. 相似文献
109.
Isa. Degirmenci Tugba Furuncuoglu Ozaltın Ozlem Karahan Veronique Van Speybroeck Michel. Waroquier Viktorya Aviyente 《Journal of polymer science. Part A, Polymer chemistry》2013,51(9):2024-2034
In this study, the relative rate of polymerization of acrylic acid (AA) versus methacrylic acid (MAA) and the effect of water on the polymerization kinetics are investigated within a combined static and molecular dynamics set of computational tools. Experimentally the relative rate of propagation of AA versus MAA is around 35 in bulk and 31 in water. Classical Molecular Dynamics calculations have been carried out to determine the location of the solvent molecules in the proximity of the dimeric poly(AA) and poly(MAA) units. A combined implicit/explicit solvent model was used for the evaluation of the kinetics of the dimeric polymer chains. We show that the rate acceleration of both polymers in water is mainly due to entropic rather than electrostatic effects and is in agreement with experimental findings. Moreover the slower propagation rate of MAA versus AA is ascribed to additional steric effects present in MAA due to the methyl group at the α position of the monomer. Among the functionals used, the M06‐2X/6‐311+G(3df,2p)//B3LYP/6‐31+G(d) methodology reproduces the experimental rate constants quantitatively the best. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
110.
Muneer Aziz Saleh Ahmad Termizi Ramli Yasser Alajerami Mohammed Damoom Abubakar Sadiq Aliyu 《Isotopes in environmental and health studies》2014,50(1):103-113
The radiation survey of the ambient environment was conducted using two gamma detectors, and the measurement results were used in the computation of the mean external radiation dose rate, mean-weighted dose rate and annual effective dose, which are 144 nGy h?1, 0.891 mSv y?1 and 178 μSv, respectively. A high-purity germanium detector was used to determine the activity concentrations of 232Th, 226Ra and 40K in soil samples. The results of the gamma spectrometry of the soil samples show radioactivity concentration ranges from 19±1 to 405±13 Bq kg?1 with a mean value of 137±5 Bq kg?1 for 232Th, from 21±2 to 268±9 Bq kg?1with a mean value of 78±3 Bq kg?1 for 226Ra and from 23±9 to 1268±58 Bq kg?1 with a mean value of 207±13 Bq kg?1 for 40K. Radium equivalent activity (Raeq) and external hazard index (Hex) were 290 Bq kg?1 and 0.784, respectively, which were safe for the population. The mean lifetime dose and lifetime cancer risk for each person living in the area with average lifetime (70 y) were 12.46 mSv and 7.25×10?4 Sv year, respectively. The results were compared with values given in United Nations Scientific Committee on the Effects of Atomic Radiation 2000. 相似文献