Trends in reinforced composite design for ionizing radiation shielding applications: a review

This review explored recent developments in reinforced composite design and applications for improved radiation shielding and high percentage attenuation. Radiation energy moves as a wave. Thus unguarded exposure to high-energy radiation is inimical to the human tissue and the overall health standing of individuals which may result in cancer, tumour, skin burns and cardiovascular diseases. Radiation energy is conventionally contained using lead-based shields. However, recent literature has faulted the continued use of lead citing drawbacks such as high toxicity, poisoning, lack of chemical stability, heaviness and hazardous after life handling. Consequently, the trending research evidence has shown mass deviation towards the use of reinforced polymer composite as an alternative to lead due to their light weight, low cost, high resilience, good mechanical tenacity and interesting electrical properties. The present review therefore summarizes the criteria for ionizing radiation shielding material design, mechanism of radiation energy shielding, beam penetration in composite shielding materials, theoretical shielding parameters in the design of radiation protective materials, scheme of reinforced composite material selection for shielding purposes and various control variables in the design of composite for ionizing radiation shielding. In addition, an attempt was made to highlight gaps in research and draw future scope for further studies. It is expected that this review will give some guidance to the future exploration in the design and application of reinforced composite with respect to ionizing radiation shielding processes.

     

Aging studies on flame retardant treated lignocellulosic fibers

The study deals with chemical and flame retardant (FR) treatment of flax fabric. Sheets of flax fabric were subjected to chemical treatments using NaOH and silane coupling agents. A phosphate‐based flame retardant (DAP) was also applied to improve the flammability of the fabric. The effects of the chemical treatments and FR treatments on flax fabric were investigated using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and vertical flame resistance test. Aging studies were carried out by exposing the samples in an environmental chamber at specified conditions for two weeks. The mechanical properties of the fabric, before and after environmental aging, were investigated. Flammability of flax fabric was improved after FR treatment. Thermal studies revealed a shift of decomposition temperature to lower temperatures and an increase in char residue after FR treatment. Despite treatment of the fabric with NaOH and silane, the tensile strength of FR‐treated flax fabric declined by more than 90% after aging for two weeks at 90 °C and 50% RH. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44175.     

Coefficient Diagram Method Based Load Frequency Control for a Modern Power System

With the increasing penetration of renewable energy sources with a wide range of operating conditions causing power system uncertainties, conventional controllers are incapable of providing proper performance to keep the system stable. However, controllable or dispatchable loads such as electric vehicles (EVs) and heat pumps (HPs) can be utilized for supplementary frequency control. This paper shows the ability of plug-in hybrid EVs, HPs, and batteries (BTs) to contribute in the frequency control of an isolated power system. Moreover, we propose a new online intelligent approach by using a coefficient diagram method (CDM) to enhance the system performance and robustness against uncertainties. The performance of the proposed intelligent CDM control has been compared with the proportional-integral (PI) controller and the superiority of the proposed scheme has been verified in Matlab/Simulink programs.     

Coefficient Diagram Method Based Load Frequency Control for a Modern Power System

With the increasing penetration of renewable energy sources with a wide range of operating conditions causing power system uncertainties,conventional controllers are incapable of providing proper performance to keep the system stable.However,controllable or dispatchable loads such as electric vehicles(EVs) and heat pumps(HPs) can be utilized for supplementary frequency control.This paper shows the ability of plug-in hybrid EVs,HPs,and batteries(BTs)to contribute in the frequency control of an isolated power system.Moreover,we propose a new online intelligent approach by using a coefficient diagram method(CDM) to enhance the system performance and robustness against uncertainties.The performance of the proposed intelligent CDM control has been compared with the proportional-integral(PI) controller and the superiority of the proposed scheme has been verified in Matlab/Simulink programs.     

Flame retardant treated flax fibre reinforced phenolic composites: Ageing and thermal characteristics

In this study, flax composites were prepared from flax fabric and phenolic resin. Chemical treatments were imparted to the fabric to improve adhesion between the fabric and the phenolic matrix. Diammonium phosphate was applied to improve the flammability of the composites. The thermal and flammability properties of the untreated, chemically treated, and flame retardant (FR) treated flax fabric reinforced phenolic composites were studied. Ageing studies were carried out by subjecting the composites to varying conditions of temperature and humidity in an environmental chamber for 2 weeks. FR treatment of flax fabric was shown to be very effective in improving flame retardancy of the composites due to decreased peak heat release rate (PHRR) and smoke production rate (SPR). Thermogravimetric analysis (TGA) of composites showed that after FR treatment, the decomposition temperatures shifted to lower temperatures. Ageing studies revealed that the mechanical properties of untreated, chemically treated and FR treated composites decreased with an increase in ageing temperature.     

Microfluidic-Generated Seeds for Gold Nanotriangle Synthesis in Three or Two Steps

Nanoparticle synthesis has drawn great attention in the last decades. The study of crystal growth mechanisms and optimization of the existing methods lead to the increasing accessibility of nanomaterials, such as gold nanotriangles which have great potential in the fields of plasmonics and catalysis. To form such structures, a careful balance of reaction parameters has to be maintained. Herein, a novel synthesis of gold nanotriangles from seeds derived with a micromixer, which provides a highly efficient mixing and simple parameter control is reported. The impact of the implemented reactor on the primary seed characteristics is investigated. The following growth steps are studied to reveal the phenomena affecting the shape yield. The use of microfluidic seeds led to the formation of well-defined triangles with a narrower size distribution compared to the entirely conventional batch synthesis. A shortened two-step procedure for the formation of triangles directly from primary seeds, granting an express but robust synthesis is further described. Moreover, the need for a thorough study of seed crystallinity depending on the synthesis conditions, which – together with additional parameter optimization – will bring a new perspective to the use of micromixers which are promising for scaling up nanomaterial production is highlighted.