Thermal and chemical properties of wool powders

Wool powders with different particle sizes were examined in terms of their crystal structures, thermal properties, surface chemical compositions and moisture regains. It was found that the crystallinity of wool powders was increased, and the moisture regains were decreased as the particle sizes of wool powders were reduced. For comparison, the properties of activated charcoal were also investigated. The higher dye uptake of activated charcoal at pH 10. compared to that of wool powder, could be due to its greater surface area and porous structure.

Supramolecular ionic networks with superior thermal and transport properties based on novel delocalized di-anionic compounds

Supramolecular ionic networks based on highly delocalized dianions having (trifluoromethane-sulfonyl)imide, (propylsulfonyl)methanide and (cyano-propylsulfonyl)imide groups were developed and their physical properties were examined in detail. Most of the synthesized compounds were semi-crystalline possessing Tm values close to 100°C; however, amorphous networks were also obtained using aromatic asymmetric dianions. Rheological measurements in temperature sweep tests at a constant frequency confirmed two different behaviors: a fast melting close to the Tm for semi-crystalline materials and a thermoreversible network for liquid transition for the amorphous supramolecular ionic networks. It was found that the amorphous ionic networks showed significantly higher ionic conductivity (10^-3 S cm^-1 at 100°C) than the crystalline ionic networks (10^-6 S cm^-1) and previously reported amorphous citrate ionic networks (10^-5 S cm^-1). The supramolecular ionic networks containing hydrophobic (trifluoromethanesulfonyl)imide groups demonstrated improved water stability and higher thermal stability than the previously synthesized carboxylate ones. Noticeably, the obtained amorphous supramolecular ionic networks combine not only high ionic conductivity and thermal stability, but also self-healing properties into the same material.

Thermal and rheological characteristics of biobased carbon fiber precursor derived from low molecular weight organosolv lignin

In the present work, electrospinnability as well as thermal, rheological, and morphological characteristics of low molecular weight hardwood organosolv lignin, as a potential precursor for carbon fiber, was investigated. Submicromter biobased fibers were electrospun from a wide range of polymer solutions with different ratios of organosolv lignin to polyacrylonitrile (PAN). Rheological studies were conducted by measuring viscosity, surface tension, and electrical conductivity of hybrid polymer solutions, and used to correlate electrospinning behavior of solutions with the morphology of the resultant electrospun composite fibers. Using scanning electron microscopy (SEM) images, the solutions that led to the formation of bead-free uniform fibers were found. Differential scanning calorimetry (DSC) analysis revealed that lignin-based fibers enjoy higher decomposition temperatures than that of pure PAN. Thermal stability of the lignin-based fibers was investigated by thermogravimetric analysis (TGA) indicating a high carbon yield of above 50% at 600 °C, which is highly crucial in the production of low-cost carbon fiber. It was also observed that organosolv lignin synergistically affects thermal decomposition of composite fibers. A significant lower activation energy was found for the pyrolysis of lignin-derived electrospun fibers compared to that of pure PAN.

Dependence of wool fabric dimensions on temperature and pH

Through a series of experimental analysis of temperature and pH value on the expansion of wool fiber and wool fabrics size change. In the pH2.1 solution, the wool fabric size declines with increasing temperature, changing the magnitude depends on the fabric and fabric shape rate. isoelectric point of pH4.8 in the wool, the fibers expand to reach the minimum, while the size of the fabric, along with the solution acidity increases.

Why do Australians, New Zealanders and Americans travel to Fiji? Evidence from cointegration, unit roots and parameter stability tests

The aim of this study was to estimate the demand for Fiji’s tourism from its three main source markets—Australia, New Zealand, and the US—using the bounds testing approach to cointegration. Our main finding was that visitor arrivals to Fiji and its key determinants are cointegrated over the 1970–2000 period. We then used the autoregressive distributed lag model to estimate short-run and long-run elasticities and found that income in origin countries, transport costs, and prices were significant determinants of Fiji’s tourism demand. We also found that coups negatively impact visitor arrivals from all markets. In testing for parameter stability, we established that the series were integrated of order one in the presence of a structural break. We then used the Hansen test for parameter stability and found that the parameters of our long-run model are stable over time.

Thermal and mechanical properties of a dendritic hydroxyl-functional hyperbranched polymer and tetrafunctional epoxy resin blends

Blends of a tetrafunctional epoxy resin, tetraglycidyl- 4,40'-diaminodiphenylmethane (TGDDM), and a hydroxylfunctionalized hyperbranched polymer (HBP), aliphatic hyperbranched polyester Boltorn H40, were prepared using 3,3'-diaminodiphenyl sulfone (DDS) as curing agent. The phase behavior and morphology of the DDS-cured epoxy/HBP blends with HBP content up to 30 phr were investigated by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM). The phase behavior and morphology of the DDS-cured epoxy/HBP blends were observed to be dependent on the blend composition. Blends with HBP content from 10 to 30 phr, show a particulate morphology where discrete HBP-rich particles are dispersed in the continuous cured epoxy-rich matrix. The cured blends with 15 and 20 phr exhibit a bimodal particle size distribution whereas the cured blend with 30 phr HBP demonstrates a monomodal particle size distribution. Mechanical measurements show that at a concentration range of 0–30 phr addition, the HBP is able to almost double the fracture toughness of the unmodified TGDDM epoxy resin. FTIR displays the formation of hydrogen bonding between the epoxy network and the HBP modifier.

Self-assembly and film stability of a micelle of a single-chain quaternary ammonium amphiphile containing azobenzene on mica

The self-assembling behavior of a single-chain quaternary ammonium amphiphile bearing azobenzene (C₁₂AzoC₆N⁺) on freshly cleaved mica sheet has been investigated by atomic force microscopy (AFM) method. Confocal microscopic Raman spectra confirm the adsorption of the self-assembled monolayer structure. Ex-situ AFM reveals that C₁₂AzoC₆N⁺ forms branch-like stripes indicating the fusion and reorganization of the micelles during drying in air as the in-situ AFM has revealed that surfactant forms spherical micelles on the mica surface. The nano-sized surface structure is strongly dependent on the change of molecular structure, which resulted from photo-induced isomerization. The nano-sized stripe is quite stable even being annealed at 90 °C for 4 h.

Thermal and physical properties of an archetypal organic ionic plastic crystal electrolyte

The thermal and mechanical properties of the ionic plastic crystal N-methyl-N-propylpyrrolidinium hexafluorophosphate have been investigated and the effect of adding a miscible polymer on the mechanical properties is reported. The physical properties of the pure plastic crystal are discussed in detail and for the first time the change in volume with temperature for an organic ionic plastic crystal is reported. An increase in volume in conjunction with increased conductivity supports the hypothesis that ion conduction within the plastic crystal proceeds via defects. For phase I and melting, the magnitude of the volume increase does not appear to be in accord with the subtle change in conductivity. This is suggested to be due to the presence of layer defects, which allow for correlated ionic motion, which does not increase the conductivity. Addition of polymer to the plastic crystal significantly increases the mechanical strength, decreases the conductivity, but has little effect on the phase behaviour, further supporting the hypothesis of vacancy-mediated conduction.

Evaluation of thermal and visual comfort in offices considering realistic input data and user behaviour in building simulation

Thermal and visual comfort play a very important role regarding the satisfaction of occupants with their working environments. The most effective method to achieve thermal comfort in offices is to reduce cooling loads in order to avoid additional energy-consuming devices for cooling. Building simulation software can be a helpful tool for optimisation, and typically standard values for the influencing parameters are used in order to ensure compliance to norms and regulations.

In practice many of those parameters turn out to be different compared to the simulation assumptions and the reasons may be the chosen room or building related properties as well as the user behaviour influenced by the task and the corporate culture of the company.

This paper investigates exemplary for the climate of Hamburg, Germany and a naturally ventilated typical office room, the optimisation potential of the building- and user-related parameters for thermal comfort, daylighting and view when using realistic input data for building simulation. The study has been conducted with the EnergyPlus based simulation software “Primero-Komfort” [1].

Thermal and ventilation performance of a multifunctional sports hall within an aquatic centre

There has been an increasing demand for sports facilities in urban areas recently. As a result of this, more attention is drawn towards not only the energy performance of these building typologies, but also creating a healthy indoor environment for the users. This Study investigates the thermal and ventilation performance of a sports hall within an aquatic centre using computational fluid dynamics (CFD) simulations. IES Virtual Environment software was used to perform the simulations. A number of scenarios were tested by changing the position of extract fans as well as by incorporating natural ventilation strategies. A high level of discomfort was observed in the space. Better comfort condition was achieved by changing the location of exhaust fans ad openings. The results help to recommend some guidelines to inform the proposed refurbishment plans of the site.

Thermal and mechanical properties of ultrasonically treated wool

Wool fabrics, ultrasonically treated in various chemical conditions and for different time durations, were analysed for thermal properties by thermo-gravimetric analysis and differential scanning calorimeter, in comparison with the untreated fabric. Fabric mechanical properties, such as bending and tensile performance, and changes in fibre morphology were also evaluated before and after ultrasonic treatment.It is found that wool treated with ultrasonics at the appropriate time, has less mass loss and a higher thermal degradation temperature than that without ultrasonic treatment or with prolonged ultrasonic treatment. Resistance to thermal degradation is reduced when wool is ultrasonically treated in the presence of alkali. Differential scanning calorimeter analysis shows that while ultrasonic treatment has little effect on fibre crystallinity, an appropriate treatment can provide wool with increased water absorption. Ultrasonic treatment stiffens wool fabric to some extent when the treatment time is prolonged. The addition of detergent alone to the ultrasonic bath has little effect on fabric tensile behaviour, whereas a treatment with both detergent and alkali produces severe fibre damage and significant loss of fabric tensile strength.

Who chose this restaurant anyway? The effect of responsibility for choice, guarantees and failure stability on customer complaining

Customers often behave in the context of a group, with different behavior occurring in this context to that which transpires in an individual context. However, customer complaining behavior (CCB), including voice, negative word of mouth, in addition to that transmitted electronically, and exit, in a group setting has not been studied previously. A service failure during a group celebration at a restaurant and the pattern of CCB that ensues is examined. This is based on customers’ level of responsibility in restaurant selection on behalf of the group, the presence of an unconditional service guarantee, and the perceived stability of the failure. Findings suggest that customers are more inclined to exit when they have participated to a greater degree in choice and that the presence of an unconditional guarantee interacts with participation to influence negative word of mouth intentions. Perceived failure stability had the greatest influence on CCB.

Structure and phase stability of NiMnGa ferromagnetic shape memory alloys by experimental and ab-initio techniques

This paper summarizes some of our recent results on crystal structure, microstructure, orientation relationship between martensitic variants and crystallographic features of martensitic transformation in Ni-Mn-Ga FSMAs. It was shown that Ni53Mn25Ga22 has a tetragonal I4/mmm martensitic structure at room temperature. The neighboring martensitic variants in Ni53Mn25Ga22 have a compound twinning relationship with the twinning elements K1={112}, K2={11-2}, η1=<11-1>, η2=<111>, P={1-10} and s=0.379. The ratio of the relative amounts of twins within the same initial austenite grain is ~1.70. The main orientation relationship between austenite and martensite is Kurdjumov-Sachs (K-S) relationship. Based on the crystallographic phenomenological theory, the calculated habit plane is {0.690 -0.102 0.716}A (5.95° from {101}A), and the magnitude, direction and shear angle of the macroscopic transformation shear are 0.121, <-0.709 0.105 0.698>A (6.04° from <-101>A) and 6.88°, respectively.