University of Bolton

About: University of Bolton is a education organization based out in Bolton, Manchester, United Kingdom. It is known for research contribution in the topics: Fire retardant & Higher education. The organization has 886 authors who have published 1980 publications receiving 41597 citations. The organization is also known as: Bolton Institute of Higher Education & Bolton Institute.

Fiber-reinforced epoxy composites exposed to high temperature environments. Part II: Modeling mechanical property degradation

Abstract: This article is part of a series on the thermo-mechanical responses of fiber-reinforced composites at elevated temperatures and it follows the first part containing experimental results. A flame-retardant system consisting of a cellulosic charring agent and an interactive intumescent additive (melamine phosphate) has been used in order to improve the post-fire mechanical performance of glass fiber-reinforced epoxy composites. The effect of one-sided radiant heat on the residual flexural stiffness of laminate coupons exposed to incident heat fluxes of 25 and 35kWm-2 was investigated. The flame-retarded coupons retained a higher percentage of their original room temperature flexural modulus after heat exposure while the control specimens showed inferior material property retention over the same exposure periods. A heat transfer (thermal) model based on Henderson's equation is used to predict the through thickness temperature profiles and subsequently the mass loss due to the resin matrix decomposition at elevated temperatures. The theoretical results from the heat transfer model are validated against experimentally obtained data and then coupled with a mechanics model that describes material property-temperature dependence in order to predict the residual flexural stiffness, after heat damage. The accuracy of the thermo-mechanical model was validated against the experimental data and a good agreement was observed.

Polypropylene fibers containing dispersed clays having improved fire performance. Part II: characterization of fibers and fabrics from PP–nanoclay blends

Abstract: In this second part of a series of studies on polypropylene (PP) fibers having improved fire performance and containing nanodispersed clays we build on the observations of the first part of this work (published in Journal of Applied Polymer Science), where the need to improve dispersion of nanoclays is the key to achieve significant improvement. This paper attempts to address this issue by reporting studies of the use of several different functionalized clays in the presence and absence of compatibilizing PP copolymers and also to which the flame retardant (FR), ammonium polyphosphate (APP) has been introduced. Compounded polymer samples have been characterized using X-ray diffraction (XRD), optical, and scanning electron microscopes, and their melt flow indices (MFI). These compounded polymers have been successfully extruded into filaments using a single screw extruder and then knitted into fabric samples. Filament physical properties are reported together with burning behaviors of fabric samples using limiting oxygen index (LOI) and flame spread tests. Copyright © 2008 John Wiley & Sons, Ltd.

Flexible surface acoustic wave strain sensor based on single crystalline LiNbO3 thin film

Abstract: A flexible surface acoustic wave (SAW) strain sensor in the frequency range of 162–325 MHz was developed based on a single crystalline LiNbO3 thin film with dual resonance modes, namely, the Rayleigh mode and the thickness shear mode (TSM). This SAW sensor could handle a wide strain range up to ±3500 μe owing to its excellent flexibility, which is nearly six times the detecting range of bulk piezoelectric substrate based SAW strain sensors. The sensor exhibited a high sensitivity of 193 Hz/ μe with a maximum hysteresis less than 1.5%. The temperature coefficients of frequency, for Rayleigh and TSM modes, were −85 and −59 ppm/ °C, respectively. No visible deterioration was observed after cyclic bending for hundreds of times, showing its desirable stability and reliability. By utilizing the dual modes, the strain sensor with a self-temperature calibrated capability can be achieved. The results demonstrate that the sensor is an excellent candidate for strain sensing.

Self-injurious Behavior in Zoo Primates

Abstract: Researchers have long known that social isolation of some primates, particularly in infancy, can lead to the development of abnormal behaviors including self-injurious behavior (SIB). However, SIB can also occur in non-isolate-reared primates and can be triggered by frustration or environmental events. The subjects of reports of SIB have mostly been laboratory primates, usually macaques. Researchers had not systematically studied whether SIB occurs in zoo primates, and if so to what extent. Here we report the results of a questionnaire-based survey of British and Irish zoos on the extent of SIB in zoo primates, and whether it was associated with any environmental or developmental events. Responses indicated that though SIB occurred across a range of primate species, its incidence was very low. Respondents identified a variety of environmental events as implicated in initiating SIB, and though the data set is too small to confirm them statistically, several trends were discernible. We conclude that SIB is not a major problem in zoo primates.