Managing price and service rate in customer-intensive services under social interactions

This paper investigates the price and service rate decisions in a customer-intensive service in an M/M/1 queue system under the influence of social interactions, where a higher value of the service is perceived if more customers purchase the service. The customer-intensive nature of the service requires a low service speed to maintain its quality, which may increase the congestion of the system. Two cases where customers are either homogeneous or heterogeneous in terms of the customer intensity are considered. It is found that social interactions can always benefit the service provider as more expected revenue can be achieved, and potential profits would be lost if the influence of social interactions is ignored. For the case with heterogeneous customers, the optimal price and service rate decisions are solved with or without considering social interaction effect. The study finds the proportions of high and low sensitive customers and the social interaction intensity are critical to the operational decisions and the market coverage strategies. These results offer a better understanding on the interplay between the quality-speed conundrum and the influence of social interactions in customers’ purchase behaviour in managing customer-intensive services

A Two-Step Hydrothermal Synthesis Approach to Monodispersed Colloidal Carbon Spheres

This work reports a newly developed two-step hydrothermal method for the synthesis of monodispersed colloidal carbon spheres (CCS) under mild conditions. Using this approach, monodispersed CCS with diameters ranging from 160 to 400 nm were synthesized with a standard deviation around 8%. The monomer concentration ranging from 0.1 to 0.4 M is in favor of generation of narrower size distribution of CCS. The particle characteristics (e.g., shape, size, and distribution) and chemical stability were then characterized by using various techniques, including scanning electron microscopy (SEM), FT-IR spectrum analysis, and thermalgravity analysis (TGA). The possible nucleation and growth mechanism of colloidal carbon spheres were also discussed. The findings would be useful for the synthesis of more monodispersed nanoparticles and for the functional assembly

A self-seeding coreduction method for shape control of silver nanoplates

This work reports a newly developed synthesis method, i.e., a self-seeding coreduction method, for shape control of silver nanoparticles such as triangular nanoplates and circular nanodiscs. By this method, high surface-to-volume silver nanoplates (∼2.3 nm in thickness) were successfully generated. The distinct advantages of this method include no need to add external seeds, no need to use organic solvents that are environmentally unfriendly, being able to perform at room temperature, and synergetic use of a few reducing agents for better growth control of two-dimensional nanostructures. In particular, molecular dynamics simulation is used to quantify the interaction energies between surfactant molecules and different facets of silver crystal. Such molecular information, together with measurements using x-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM) and ultraviolet–visible (UV–vis) spectroscopy, has proven to be useful in understanding the growth mechanisms of silver nanoplates

Silver nanoplates : synthesis, growth and functional properties

This chapter provides a brief review of the recent research on silver nanoplates, covering the synthesis, growth mechanisms, and functional properties, with a focus on our work in this field. Various methods for the synthesis of silver nanoplates (eg. triangles, disks, and prisms) are first introduced, including physical technique (eg. nanosphere lithographic method) and chemical techniques (eg. photoinduced method, templating method, solvothermal and hydrothermal reduction methods). A synergetic reduction hydrothermal method developed by our lab, namely, the use of three or more reducing agents simultaneously for the synthesis of silver nanoplates at ambient conditions, will be discussed in detail. Then, various experimental and theoretical techniques employed for understanding the principles underlying the growth and shape control of nanoparticles are discussed, including the use of molecular dynamics (MD) and density function theory (DFT) simulations. Finally, the functional properties of silver nanoparticles (eg. surface enhancement Raman spectrum, and localized surface Plasmon resonances) in chemical and biochemical sensing, as well as the stability and chemical reactivity are summarized based on the recent findings to highlight the potential of silver nanoplates. The need for future research is also briefly discussed

Self-assembly of particles : some thoughts and comments

Self-assembly can happen to particles at all length scales, including atomic, nano-, meso- and macro-particles. Although widely used in nanoresearch, many nano-structures reported in the literature are not self-assembled, posing some fundamental questions. This paper will briefly review this topic, answering the following questions: what is the current status in self-assembling nanoparticles? Why is it so difficult to produce self-assembled structures of nanoparticles? How can we effectively overcome the difficulty? The important role of controlling forces of various types in relation to different self-assembly techniques is discussed. Self-assembly is demonstrated as a complex problem that still needs intensive multi-scaled studies

Molecular understanding of the deposition of gold nanoclusters on TiO2(110)

The deposition of gold nanoclusters on rutile TiO2(110) surface is investigated by molecular dynamics simulation, with special reference to the effects of surface defect types (i.e., point, step, and groove) and deposition temperature. The results show that gold nanoclusters can be strongly attracted to the surface and a higher degree of defect results in a stronger attractive interaction. In addition, the aggregation behavior of gold nanoclusters is studied by simulation and experiment. The results indicate that the aggregation can be effectively controlled by introducing suitable surface defects or adding citrate ions into the solution. The findings are useful to the design and fabrication of supported Au–TiO2 catalysts with high catalytic activity

Experimental and numerical study of cetyltrimethylammonium bromide (CTAB)-directed synthesis of goethite nanorods

This study demonstrates a facile surfactant-directed approach to prepare goethite (α-FeOOH) nanorods in aqueous solution at room temperature. The obtained α-FeOOH nanorods have a diameter of ∼20 nm and length up to 300 nm. Various experimental parameters have been investigated, such as surfactants, solution pH, and reaction temperature. It is observed that the surfactant, cetyltrimethylammonium bromide (CTAB), plays a key role in the growth of goethite nanorods at ambient conditions. The final product can be purified using diluted hydrochloric acid (HCl) to remove particles of other shapes. Molecular dynamics (MD) method is used to understand the underlying principles governing particle growth through the analysis of the interaction energies between crystal surfaces and surfactant molecules. The simulation results indicate that CTAB can strongly interact with {100}, {010}, and {110} planes, which benefits the growth of nanorods along [001] direction. Such simulations can provide useful information for the synthesis and shape control of other metal oxide materials