Isothermal transient ionic current study of laminated electrochromic devices for smart window applications

The isothermal transient ionic current (ITIC) in three different kinds of laminated electrochromic devices has been determined. The devices consisted of one 300 nm thick layer of nickel oxide and one 300 nm thick layer of WO₃ deposited onto separate In₂O₃:Sn (ITO) covered glass substrates by DC magnetron sputtering at room temperature. They were then laminated with a polymeric ion conductor, acting as electrolyte, in symmetric and asymmetric configurations, i.e. WO₃/WO₃, NiO_xV_yH_z/NiO_xV_yH_z and WO₃/NiO_xH_y. The electrolyte was prepared by mixing polyethylene glycol of average molecular weight 400 (PEG 400) and lithium triflouromethanesulfonate (LiSO₃CF₃) for 12 h at 70°C and with a ratio oxygen/lithium (O/Li)=10. The samples were first polarized, i.e. the ions are transported to one of the electrodes, which in the asymmetric devices is the nickel oxide electrode. At the first applied potential step, the ions move through the electrolyte towards the opposite electrode. The potential is then switched and the ions move back to the first electrode. The ITIC curves are found to depend on the electrode material and in the asymmetric case also the direction of the ion current.     

Optical properties of electrochromic all-solid-state devices

We have investigated the optical properties of an all-thin-film electrochromic device, with a thin film of ZrO₂ acting as an ion conductor. The device also employed electrochromic layers of amorphous or crystalline WO₃ and NiV_xO_yH_z. Transmission (T) and reflection (R) spectra were recorded in the wavelength range 300–2500 nm at different intercalation levels, both for single films and complete devices. The results show that T decreases significantly upon intercalation in the WO₃ thin films as well as in the devices. The reflectance only shows minor changes.     

Investigation and Characterization of Lignin Precipitation in the LignoBoost Process

Lignin of high purity can be separated from black liquor using the LignoBoost process, of which the overall efficiency is largely dependent on the precipitation yield of lignin, which depends on the properties of black liquor and process conditions. In this paper, the influences of process conditions on the precipitation yield of lignin from mixed hardwood/softwood black liquor were investigated. The Klason and standard UV method were used to determine lignin concentration. The chemical and structural properties of lignin were also analyzed. The results showed that the precipitation yield of lignin increased along with a decrease in pH and temperature, or with an increase in the ion strength of black liquor, and the yield was lower when mixed softwood/hardwood black liquor was used. It also showed that at a higher precipitation yield the precipitated lignin had a lower average molecular weight but had higher methoxyl and phenolic hydroxyl content.     

Prediction of groutability from grout properties and hydrogeological data

Sealing tunnels and caverns in fractured crystalline rocks has been considered notoriously unpredictable and possible to manage only through experience and intuitive knowledge. Words such as “witchcraft” and “black art” have been used ironically in Sweden to describe the state of the art. In this paper, initially grout penetration and grout take in parallell planar fractures are discussed. General expressions for these entities are also derived for fractures with varying width. In this paper, the grout take of a system of inhomogeneous channels in a fracture plane is studied further and the grout takes of such systems are modelled numerically. Grout takes are calculated for increased variability of the fracture aperture and the influence of this is assessed. In normal Swedish grouting procedures, the grouting boreholes are tested by water pressure tests (WPT). The hydrogeological information from these tests can be transferred to grouting apertures, and thus yield design information for grouting operations. Finally, the applicability of the findings is evaluated using field data from grouting of the access tunnel of the Äspö Hard Rock Laboratory, Sweden. The conclusion is that field methods for prediction and design of grouting operations can successfully be based on the theory.     

A robust method to determine the shear strength of cement-based injection grouts in the field

There is no standardised method to directly determine the shear strength of grouts in the field. Determining the shear strength would make it possible to calculate the penetration length of cement-based grouts and hence establish a design of the grouting procedure. By developing a new robust method that consists of a stick sinking in the grout, a direct measurement of the shear strength can be made, using the same set up as the separation test. The sink of the stick depends on the shear force interaction between the grout and the stick, and hence the shear strength of the grout can be determined. To verify the results, the shear strengths obtained with the stick are compared with measurements of the shear strength made with a rotational rheometer in the laboratory. The comparison shows good agreement; hence the stick can be used in the field to determine the yield strength of cement-based grouts.     

Trapping ring electrode cell: a FTICR mass spectrometer cell for improved signal-to-noise and resolving power

A novel FTICR cell called the trapping ring electrode cell (TREC) has been conceived, simulated, developed, and tested. The performance of the TREC is compared to a closed cylindrical cell at different excited cyclotron radii. The TREC permits the ability to maintain coherent ion motion at larger initial excited cyclotron radii by decreasing the change in radial electric field with respect to z-axis position in the cell. This is accomplished through postexcitation modulation of the trapping potentials applied to segmented trap plates. Resolving power approaching the theoretical limit was achieved using the novel TREC technology; over 420,000 resolving power was observed on melittin [M + 4H] (4+) species when employed under modest magnetic field strength (3T) and a data acquisition duration of 13 s. A 10-fold gain in signal-to-noise ratio is demonstrated over the closed cylindrical cell optimized with common potentials on all ring electrodes. The observed frequency drift during signal acquisition over long time periods was also significantly reduced, resulting in improved resolving power.     

A multimeric quinacrine conjugate as a potential inhibitor of Alzheimer's beta-amyloid fibril formation

Amyloid formation and accumulation of the amyloid beta-peptide (Abeta) in the brain is associated with Alzheimer's disease (AD) pathogenesis. Therefore, among the therapeutic approaches in development to fight the disease, the direct inhibition of the Abeta self-assembly process is currently widely investigated and is one of the most promising approaches. In this study we investigated the potential of a multimeric display of quinacrine derivatives, as compared to the monomer quinacrine, as a design principal for a novel class of inhibitors against Abeta fibril formation. The presented multimeric conjugate exhibits a cluster of four quinacrine derivatives on a rigid cyclopeptidic scaffold. Herein is reported the synthesis of the conjugate, together with the in vitro inhibitory evaluation of Abeta(1-40) fibrils using the thioflavin T fluorescence assay, and imaging with atomic force microscopy. Our data show that the multimeric compound inhibits Abeta(1-40) fibril formation with an IC(50) value of 20+/-10 microM, which contrasts with the nonactive monomeric analogue. This work suggests that assembling multiple copies of acridine moieties to a central scaffold, for multiple interactions, is a promising strategy for the engineering of inhibitors against Abeta fibril formation.     

Organosulfates as Tracers for Secondary Organic Aerosol (SOA) Formation from 2-Methyl-3-Buten-2-ol (MBO) in the Atmosphere

2-Methyl-3-buten-2-ol (MBO) is an important biogenic volatile organic compound (BVOC) emitted by pine trees and a potential precursor of atmospheric secondary organic aerosol (SOA) in forested regions. In the present study, hydroxyl radical (OH)-initiated oxidation of MBO was examined in smog chambers under varied initial nitric oxide (NO) and aerosol acidity levels. Results indicate measurable SOA from MBO under low-NO conditions. Moreover, increasing aerosol acidity was found to enhance MBO SOA. Chemical characterization of laboratory-generated MBO SOA reveals that an organosulfate species (C(5)H(12)O(6)S, MW 200) formed and was substantially enhanced with elevated aerosol acidity. Ambient fine aerosol (PM(2.5)) samples collected from the BEARPEX campaign during 2007 and 2009, as well as from the BEACHON-RoMBAS campaign during 2011, were also analyzed. The MBO-derived organosulfate characterized from laboratory-generated aerosol was observed in PM(2.5) collected from these campaigns, demonstrating that it is a molecular tracer for MBO-initiated SOA in the atmosphere. Furthermore, mass concentrations of the MBO-derived organosulfate are well correlated with MBO mixing ratio, temperature, and acidity in the field campaigns. Importantly, this compound accounted for an average of 0.25% and as high as 1% of the total organic aerosol mass during BEARPEX 2009. An epoxide intermediate generated under low-NO conditions is tentatively proposed to produce MBO SOA.