Water softening using a light-responsive, spiropyran-modified nanofiltration membrane

A novel technique for the covalent attachment of a light-responsive spiropyran onto polyamide thin film composite nanofiltration (NF) membranes in a one-step reaction using low-energy electron beam technology is described. The effect of illumination of the immobilized spiropyran was studied, as well as the resulting membrane properties with respect to MgSO4 retention, water permeability rate, and chlorine resistance. Electron beam irradiation showed a direct effect on the transformation of the rough PA NF membrane surface into a ridge-and-valley structure. Upon UV light irradiation, the spiropyran transformed into zwitterionic merocyanine, which had shown MgSO4 removal of >95% with water permeation rates of 6.5 L/(m2·h·bar). Alternatively, visible light was used to convert merocyanine to spiropyran, which achieved >95% of MgSO4 retention with a water flux of around 5.25 L/(m2·h·bar). The modified NF membranes showed higher chlorine resistance as well as a higher normalized water flux as compared to the reference membrane, without a loss of ion retention. All the NF membranes were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. This study demonstrates a simple and inexpensive method for the immobilization of molecules onto polymeric membranes, which may be applied in water softening

A three-dimensional customer commitment model : its impact on relational outcomes

Customer's ever increasing bargaining power makes it particularly important that practitioners and researchers more thoroughly understand the complex nature of customer commitment. Not surprisingly, however, although the construct of commitment has emerged as one of the key constructs in relationship marketing and has been widely studied in literature, there has been very little agreement on the conceptualisation of the construct. Building upon relationship marketing and organisational behaviour literature, the aim of this research is to extend our understanding of the nature of customer commitment by developing a three-dimensional customer commitment model relaying on commitment theory from the organisational behaviour literature; affective desire-based (AC), calculative cost-based (CC), and normative obligation-based (NC). Relationships among the commitment dimensions and relationships with a number of loyalty relational outcomes, namely, intention to stay (ITS), word of mouth (WOM), and willingness to pay (WTP) were investigated in this study. Using survey questionnaire distributed among customers of cell phone services (N=525), the data was analysed by structural equation modeling (SEM) and then additional analysis was employed to further demystify the complexity of the commitment concept. The results suggest that AC is the dominant source that generates customer loyalty, in line with the state of literature. Both cost-based and surprisingly obligation-based have shown detrimental effects on maintaining and developing the customer-service provider relationship. Additional analysis with various scenarios was implemented using mean split as cut score for high/low commitment dimensions. The findings suggest NC turns to have important positive role on relational outcomes when both AC and CC are below the mean split. When both AC and CC are high NC negatively affect at least ITS but at the same time make a clear positive effect on WTP. The findings can be instructional for identifying how firms can bend various marketing sources to secure more loyal customers to the service provider.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

A three-dimensional customer commitment model : its impact on relational outcomes

Customer's ever increasing bargaining power makes it particularly important that practitioners and researchers more thoroughly understand the complex nature of customer commitment. Not surprisingly, however, although the construct of commitment has emerged as one of the key constructs in relationship marketing and has been widely studied in literature, there has been very little agreement on the conceptualisation of the construct. Building upon relationship marketing and organisational behaviour literature, the aim of this research is to extend our understanding of the nature of customer commitment by developing a three-dimensional customer commitment model relaying on commitment theory from the organisational behaviour literature; affective desire-based (AC), calculative cost-based (CC), and normative obligation-based (NC). Relationships among the commitment dimensions and relationships with a number of loyalty relational outcomes, namely, intention to stay (ITS), word of mouth (WOM), and willingness to pay (WTP) were investigated in this study. Using survey questionnaire distributed among customers of cell phone services (N=525), the data was analysed by structural equation modeling (SEM) and then additional analysis was employed to further demystify the complexity of the commitment concept. The results suggest that AC is the dominant source that generates customer loyalty, in line with the state of literature. Both cost-based and surprisingly obligation-based have shown detrimental effects on maintaining and developing the customer-service provider relationship. Additional analysis with various scenarios was implemented using mean split as cut score for high/low commitment dimensions. The findings suggest NC turns to have important positive role on relational outcomes when both AC and CC are below the mean split. When both AC and CC are high NC negatively affect at least ITS but at the same time make a clear positive effect on WTP. The findings can be instructional for identifying how firms can bend various marketing sources to secure more loyal customers to the service provider.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Analysis and Modification of a Particle Filter Algorithm for Sensorless Control of BLDC Machine

This paper investigates the performance of a newly developed particle filter (PF) algorithm for sensorless control of the Brushless DC (BLDC) machines. A number of modifications have also been incorporated to the proposed PF algorithm in order to improve its performance with respect to resampling process and robust operation when unpredicted disturbances are occurred. The disturbances investigated in this paper include the presence of unconventional Non-Gaussian noises, changes in machine’s parameters, and occurrence of inter-turn short circuit fault. In addition, the paper proposes several measures in order to improve the estimation accuracy of the filter and enhance the filter robustness against system uncertainties. In order to evaluate the performance of the PF algorithm, the sensorless control system of a 1.5 kW BLDC machine is simulated in MATLAB/Simulink environment. Simulation results show that the introduced techniques considerably improve the performance of the PF algorithm as state estimator

Monte Carlo simulation for investigation of morphology dependent charge transport in bulk-heterojunction organic solar cells

Morphology, the spatial distribution of traps, interdomain connectivity, and phase separation of the active layer play a critical role in the performance of the bulk heterojunction (BHJ) organic solar cells (OSCs). In this work, we utilize the hopping transport model to simulate the effect of morphological and structural parameters on the diffusion coefficient and efficiency of the polymer-fullerene BHJ solar cells. In BHJ solar cells there are two distinct phases as electron transport material (acceptor) and hole transport material (donor). Here we try to create an almost realistic network containing P3HT polymer chains and PCBM clusters for simulating the charge transport in the active layer. The blend ratio of P3HT:PCBM polymers and alignment of these bicontinuous networks of active layer are considered here as the morphological parameter affecting the cell performance. The dependency of the charge transport on such morphological parameters is obtained in this study by using Monte Carlo continues time random walk simulations