4,329 research outputs found
CGE models for the Energy-Economy-Environment (EEE) analyses
No full textWritten evidence submitted to the environmental audit committee of the UK Parliament for the Sustainability and HM Treasury inquiry
Tetrel–Hydride Interaction between XH<sub>3</sub>F (X = C, Si, Ge, Sn) and HM (M = Li, Na, BeH, MgH)
No full textA tetrel–hydride
interaction was predicted and characterized
in the complexes of XH<sub>3</sub>F···HM (X = C, Si,
Ge, Sn; M = Li, Na, BeH, MgH) at the MP2/aug-cc-pVTZ level, where
XH<sub>3</sub>F and HM are treated as the Lewis acid and base, respectively.
This new interaction was analyzed in terms of geometrical parameters,
interaction energies, and spectroscopic characteristics of the complexes.
The strength of the interaction is essentially related to the nature
of X and M groups, with both the larger atomic number of X and the
increased reactivity of M giving rise to a stronger tetrel–hydride
interaction. The tetrel–hydride interaction exhibits similar
substituent effects to that of dihydrogen bonds, where the electron-donating
CH<sub>3</sub> and Li groups in the metal hydride strengthen the binding
interactions. NBO analyses demonstrate that both BD<sub>H–M</sub> → BD*<sub>X–F</sub> and BD<sub>H–M</sub> →
BD*<sub>X–H</sub> orbital interactions play the stabilizing
role in the formation of the complex XH<sub>3</sub>F···HM
(X = C, Si, Ge, and Sn; M = Li, Na, BeH, and MgH). The major contribution
to the total interaction energy is electrostatic energy for all of
the complexes, even though the dispersion/polarization parts are nonnegligible
for the weak/strong tetrel–hydride interaction, respectively
Superconductors in alternating fields
No full textAfter a general introduction to the fundamentals of superconductivity, the concept of the critical state is introduced and its application to alternating field conditions discussed. A comprehensive review of the a.c. measurements in the literature and the relevance to the predictions of the theories is then given. Details of the comprehensive experimental facilities constructed are described, including the development of a sophisticated technique for the measurement of a.c. losses. The equipment is essentially a sensitive wattmeter, with a small analogue computer used to operate on the voltages, from pickup-coils wound directly on the samples.
The experiments reported start with work undertaken to
investigate the dissipation in applied fields, below the critical field. The part played by surface irregularities is explored and the general field dependence of the losses explained on a simple model. A large section is then devoted to the response of type II superconductors to large fields. Results are given on high-K materials and on both reversible and hysteretic niobium samples. The predictions of the critical state model are found to hold, if suitable modifications are made to account for the field region below Rcl and the surface currents. In particular, the applied field Hm can be replaced by (Hm - .6.H/2),where AH is the overall shielding effect of the surface currents. The value of these currents has been determined from the pickup-coil voltage waveforms and the interpretation of these waveshapes has also been advanced to determine the critical current density. A decrease in the surface currents, with roughening of the sample surface, is described, and their variation with bulk properties discussed. A correlation between the critical current density and the surface currents has been discovered, and examined on the basis of "surface barrier" pinning
Discussion: Remoulded shear strength at plastic and semi-solid states
No full textThe undrained shear strength of remoulded soils is of great concern in geotechnical engineering applications. This study aims to develop a reliable approach for determining the undrained shear strength of remoulded fine-grained soils, through the use of index test results, at both the plastic and semi-solid states of consistency. Experimental investigation and subsequent analysis involving a number of fine-grained soils of widely varying plasticity and geological origin have led to a two-parameter linear model of the relationship between logarithm of remoulded undrained shear strength and liquidity index. The numerical values of the parameters are found to be dependent to a lesser extent on the soil group and to a greater extent on the soil state. Based on the values of regression coefficient, ranking index and ranking distance, it seems that the relationship represents the experimental results well. It may be pointed out that the possibility of such a relationship in the semi-solid state of a soil has not been explored in the past. It is also shown that the shear strength at the plastic limit is about 32–34 times that at the liquid limit
An assessment of the impact of possible CAP reform scenarios on Romanian agriculture
No full textUsing a simplified model, with key-variable the prices of two different possible scenarios of CAP reform after 2013 (moderate and radical), this paper present a comparison between the price effects of implementation of each reform scenario at 2015 horizon on Romanian agriculture. This short analysis shows that, under the presented hypotheses, the net welfare effect, due to the price changes, for the selected products, is positive in both reform scenarios, yet greater in the case of the radical reform. Integrated in the large context of Romanian development, it seems that the influence of CAP reform upon agriculture and rural areas will be most likely a gradual one: an interpenetration between the two scenarios is foreseeable, starting with the moderate reform that will dominate the period around 2013, the reform measures acquiring a more radical character afterwards.CAP reform, Romania, welfare effects, Agricultural and Food Policy,
Modelling transport and fate of heavy metals at the watershed scale: state-of-the-art and future directions
No full textA predictive understanding of the source-specific (e.g., point and diffuse sources) land-to-river heavy metal (HM) loads and HM dynamics in rivers is essential for mitigating river pollution and developing effective river basin management strategies. Developing such strategies requires adequate monitoring and comprehensive models based on a solid scientific understanding of the watershed system. However, a comprehensive review of existing studies on the watershed-scale HM fate and transport modeling is lacking. In this review, we synthesize the recent developments in the current generation of watershed-scale HM models, which cover a wide range of functionalities, capabilities, and spatial and temporal scales (resolutions). Existing models, constructed at various levels of complexity, have their strengths and weaknesses in supporting diverse intended uses. Additionally, current challenges in the application of watershed HM modeling are covered, including the representation of in-stream processes, organic matter/carbon dynamics and mitigation practices, the issues of model calibration and uncertainty analysis, and the balance between model complexity and available data. Finally, we outline future research requirements regarding modeling, strategic monitoring, and their combined use to enhance model capabilities. In particular, we envisage a flexible framework for future watershed-scale HM models with varying degrees of complexity to accommodate the available data and specific applications
A Markov-Switching Vector Equilibrium Correction Model of the UK Labour Market
No full textThere is a wide literature on the dynamic adjustment of employment and its relationship with the business cycle. In this paper we present a statistical model that offers a congruent representation of part of the UK labour market since the mid 1960s. We use a cointegrated vector autoregressive Markov-switching model in which some parameters change according to the phase of the business cycle. Output, employment, labour supply and real earnings are found to have a common cyclical component. The long run dynamics are characterized by one cointegrating vector relating unemployment to trend-adjusted real wages and output. Despite there having been many changes affecting this sector of the UK economy, the Markov-switching vector-equilibrium-correction model with three regimes (representing recession, normal growth, and high growth) provides a good characterization of the sample data, and performs well relative to alternative linear and non-linear models. The results of an impulse-response analysis highlight the dangers of using VARs when the constancy of the estimated coefficients has not been established, and demonstrate the advantages of generating regime dependent responses
Vibrational properties of Ge- and Sb-adsorbed Si(001) surfaces
No full textWe report on vibrational properties obtained within the adiabatic bond-charge model for (2x1) reconstructed monolayer Ge- and Sb-adsorbed Si(001) surfaces. The phonon spectra of these surfaces are compared in detail with that of the clean Si(001)(2x1) surface presented in a similar recent study. We observe that acoustic-phonon modes on the covered surfaces are mainly localized in the adsorbate layers, while high-energy optical phonon modes are localized in the top few substrate layers. This phenomenon is attributed to the large mass difference between Sb (Ge) and Si atoms. Adsorption of these overlayers is shown to result. in characteristic new peaks in the phonon density of slates, which, together with differences in polarization of certain gap phonon modes, provide a distinct signature for each overlayer system. [S0163-1829(98)02140-7]
Albumin Fusion at the N-Terminus or C-Terminus of HM-3 Leads to Improved Pharmacokinetics and Bioactivities
No full textHM-3, an integrin antagonist, exhibits anti-tumor biological responses and therefore has potential as a therapeutic polypeptide. However, the clinical applications of HM-3 are limited by its short half-life. In this study, we genetically fused human serum albumin (HSA) to the N or C-terminus of HM-3 to improve HM-3 pharmacokinetics. HM-3/HSA proteins were successfully expressed in Pichia pastoris and displayed improved pharmacokinetic properties and stability. Among them, the half-life of HM-3-HSA was longer than HSA-HM-3. In vitro, the IC50 values of HSA-HM-3 and HM-3-HSA were 0.38 ± 0.14 μM and 0.25 ± 0.08 μM in B16F10 cells, respectively. In vivo, the inhibition rates of B16F10 tumor growth were 36% (HSA-HM-3) and 56% (HM-3-HSA), respectively, indicating antitumor activity of HM-3-HSA was higher than HSA-HM-3. In conclusion, these results suggested that the HM-3/HSA fusion protein might be potential candidate HM-3 agent for treatment of melanoma and when HSA was fused at the C-terminus of HM-3, the fusion protein had a higher stability and activity
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