Testing the dimensionality of the quality management construct

© 2014 Taylor & Francis. Numerous empirical studies have conceptualised quality management (QM) as either a multidimensional or unidimensional construct. While few prior studies tested some aspects of the assumed dimensional structure of the construct, no study has been found to have tested the construct's dimensionality using alternative factor analysis models. To gain a better insight into dimensional properties of the QM construct, this paper tests its dimensionality using three confirmatory factor analysis models (oblique factor model, higher-order factor model, and one-factor model) on a subset of data collected in a larger study that investigated the effects of QM on competitive advantage using a sample of 288 hotel managers in Egypt. The results of the three tests indicate that the QM construct is multidimensional. While this study contributes to advancing the QM theory and practice, further studies are needed to investigate the dimensional properties of the construct in greater depth. The results of this study may therefore stimulate research in this area and encourage the much needed debate on the dimensionality of the QM construct

4D Printing of origami structures for minimally invasive surgeries using functional scaffold

Origami structures have attracted attention in biomedical applications due to their ability to develop surgical tools that can be expanded from a minimal volume to a larger and functional device. On the other hand, four-dimensional (4D) printing is an emerging technology, which involves 3D printing of smart materials that can respond to external stimuli such as heat. This short communication introduces the proof of concept of merging origami and 4D printing technologies to develop minimally invasive delivery of functional biomedical scaffolds with high shape recovery. The shape-memory effect (SME) of the PLA filament and the origami designs were also assessed in terms of deformability and recovery rate. The results showed that herringbone tessellation origami structure combined with internal natural cancellous bone core satisfies the design requirement of foldable scaffolds. The substantial and consistent SME of the 4D printed herringbone tessellation origami, which exhibited 96% recovery compared to 61% for PLA filament, was the most significant discovery of this paper. The experiments demonstrated how the use of 4D printing in situ with origami structures could achieve reliable and repeatable results, therefore conclusively proving how 4D printing of origami structures can be applied to biomedical scaffolds

3DP printing of oral solid formulations: a systematic review

Three-dimensional (3D) printing is a recent technology, which gives the possibility to manufacture personalised dosage forms and it has a broad range of applications. One of the most developed, it is the manufacture of oral solid dosage and the four 3DP techniques which have been more used for their manufacture are FDM, inkjet 3DP, SLA and SLS. This systematic review is carried out to statistically analyze the current 3DP techniques employed in manufacturing oral solid formulations and assess the recent trends of this new technology. The work has been organised into four steps, (1) screening of the articles, definition of the inclusion and exclusion criteria and classi-fication of the articles in the two main groups (included/excluded); (2) quantification and charac-terisation of the included articles; (3) evaluation of the validity of data and data extraction process; (4) data analysis, discussion, and conclusion to define which technique offers the best properties to be applied in the manufacture of oral solid formulations. It has been observed that with SLS 3DP technique, all the characterisation tests required by the BP (drug content, drug dissolution profile, hardness, friability, disintegration time and uniformity of weight) have been performed in the majority of articles, except for the friability test. However, it is not possible to define which of the four 3DP techniques is the most suitable for the manufacture of oral solid formulations, because the selection is affected by different parameters, such as the type of formulation, the physi-cal-mechanical properties to achieve. Moreover, each technique has its specific advantages and disadvantages, such as for FDM the biggest challenge is the degradation of the drug, due to high printing temperature process or for SLA is the toxicity of the carcinogenic risk of the photopoly-merising material

AC/DC Smart Control and Power Sharing of DC Distribution Systems

The purpose of this research is to develop a grid connected DC distribution system to ensure efficient integration of different alternate sources to the power system. An investigation of different AC and DC converter topologies and their control is conducted. A new converter topology for sharing DC power was developed to enhance the efficiency and stability of the alternate sources connected to the DC Distribution System. Mathematical model and control system design of the developed converters were included in the thesis. A novel smart-PID controller for optimal control of DC-DC converter was used as voltage controller in PV systems. This controller maximizes the stable operating range by using genetic algorithm (GA) to tune the PID parameters ultimately at various loading conditions. A fuzzy logic approach was then used to add a factor of intelligence to the controller such that it can move among different values of proportional gain, derivative gain, and integral gain based on the system conditions. This controller allows optimal control of boost converter at any loading condition with no need to retune the parameters or possibility of failure. Moreover, a novel technique to move between the PI and PID configurations of the controller such that the minimum overshoot and ripple are achieved. This increases the controller applicability for utilization of PV systems in supplying sensitive loads. An effective algorithm for optimizing distribution system operation in a smart grid, from cost and system stability points of view, was developed. This algorithm mainly aims to control the power available from different sources so they satisfy the load demand with the least possible cost while giving the highest priority to renewable energy sources. Moreover, a smart battery charger was designed to control the batteries and allow them to discharge only when there is a small load predicted. During the period they become available, they act as a buffer for the predicted large load to increase the stability of the system and reduce voltage dips

Fabrication and characterization of oxygen-generating polylactic acid/calcium peroxide composite filaments for bone scaffolds

The latest advancements in bone scaffold technology have introduced novel biomaterials that have the ability to generate oxygen when implanted, improving cell viability and tissue maturation. In this paper, we present a new oxygen-generating polylactic acid (PLA)/calcium peroxide (CPO) composite filament that can be used in 3D printing scaffolds. The composite material was prepared using a wet solution mixing method, followed by drying and hot melting extrusion. The concentration of calcium peroxide in the composite varied from 0% to 9%. The prepared filaments were characterized in terms of the presence of calcium peroxide, the generated oxygen release, porosity, and antibacterial activities. Data obtained from scanning electron microscopy and X-ray diffraction showed that the calcium peroxide remained stable in the composite. The maximum calcium and oxygen release was observed in filaments with a 6% calcium peroxide content. In addition, bacterial inhibition was achieved in samples with a calcium peroxide content of 6% or higher. These results indicate that an optimized PLA filament with a 6% calcium peroxide content holds great promise for improving bone generation through bone cell oxygenation and resistance to bacterial infections

NDM-530: AERODYNAMIC OPTIMIZATION TO REDUCE WIND LOADS ON TALL BUILDINGS

Wind is one of the governing load cases for tall building design, which produces high level of straining actions, deflections and lateral and transverse vibrations. Keeping those vibrations within the comfort limits is becoming a key aspect in tall building design, especially for buildings with high aspect ratio. Improving the aerodynamic performance of the tall building by modifying its shape can lower building motions, which reduces the additional expenses for external damping systems and alleviate the high cost associated with lateral support systems. In the present study, an aerodynamic shape optimization procedure is developed by combining Computational Fluid Dynamics (CFD), optimization algorithm and Artificial Neural Network (ANN). The developed procedure utilizes ANN as a surrogate model for evaluating aerodynamic properties, which is pre-trained using two-dimensional CFD analysis. The current study investigates the validity of the developed procedure by conducting a high accuracy, three-dimensional Large Eddy Simulation (LES) based analysis on the optimal building shapes. It was observed that utilizing two-dimensional CFD simulations in the optimization procedure can help identify effective cross-sections of tall buildings

NDM-529: NUMERICAL EVALUATION OF WIND LOADS ON A TALL BUILDING LOCATED IN A CITY CENTRE

Estimation of wind-induced loads and responses is an essential step in tall building design process. Wind load for super tall buildings is commonly evaluated using boundary layer wind tunnel (BLWT) tests. However, the recent development in computational power and techniques is encouraging designers to explore numerical wind load evaluations using a Computational Fluid Dynamics (CFD) approaches. CFD can provide a faster estimation for building loads and responses with lower cost and satisfactory accuracy for preliminary design stages. The current study investigates the accuracy of evaluating wind pressure and building responses of a typical tall building (CAARC building). Two configurations are investigated, which are (1) standalone building and (2) located in a city center. Large Eddy Simulation (LES) numerical model is utilized adopting a newly developed synthesizing turbulence generator named Consistent Discrete Random Flow Generator (CDRFG). The adopted inflow technique is believed to provide good representation of wind statistics (i.e. velocity and turbulence profiles, spectra and coherency). Pressure distributions and building responses from the current study match with those obtained from boundary layer wind tunnel tests. The average difference between the pressure values between the current model and the BLWT is 4%. While the difference in building responses resulted from the LES model to those from BLWT is 6%. It was found that utilizing CDRFG in LES models provides an accurate estimation for building aerodynamic performance in an efficient computational time owing to its capability of supporting parallel processing

Tourists’ selfies storytelling: Preferences, intentions, and concerns for practise in the tourism and hospitality industry

Photography has recently received significant academic interest as a popular tourist activity. However, tourist selfie practises have not yet been thoroughly examined by tourism scholars. This study aimed to investigate tourist selfies storytelling and to determine if tourists'selfies at tourist destinations reveal specific aspects of the host destination, implying an embodiment of particular preferences, intentions, and motivations. In this study, an exploratory analysis employing a two-step qualitative approach was conducted. A semiotic analysis of 317 tourist selfie photos and two phases of in-depth interviews with eleven tourists visiting Egypt on a 7-day packaged tour were used. The findings reveal that tourists prefer to capture host communities’ appearance and attributes in their selfies for different motivations and intentions. Intentions regarding impressions, advertisements, suggestions, and descriptions for these attributes were the intentions that shaped the tourists’ selfie practise. This study contributes to our understanding of the content of travel-related selfies and tourist behaviour at destinations. It proposes management implications to assist tourism and hospitality professionals in engaging with and profiting from tourists’ selfies practise

Fatty acid microemulsion for the treatment of neonatal conjunctivitis : quantification, characterisation and evaluation of antimicrobial activity

Fatty acids (FAs) are used by many organisms as defence mechanism against virulent bacteria. The high safety profile and broad spectrum of activity make them potential alternatives to currently used topical antibiotics for the treatment of eye infections in neonates. The current study utilised a Design of Experiment approach to optimise the quantification of five fatty acids namely; lauric acid, tridecanoic acid, myristoleic acid, palmitoleic acid and α-linolenic acid. The significance of the influence of the experimental parameters such as volume of catalyst, volume of n-hexane, incubation temperature, incubation time and the number of extraction steps on derivatisation was established by statistical screening with a factorial approach. Derivatisation was confirmed using attenuated total reflectance infrared (ATR) and 1H NMR spectrum. A gas chromatographic method (GC-FID) was developed and validated according to ICH guidelines for the identification and quantification of fatty acids. The results were found to be linear over the concentration range studied with coefficient of variation greater than 0.99 and high recovery values and low intra-day and inter-day variation values for all FAs. Then, different α-linolenic acid-based microemulsions (MEs) were prepared using Tween 80 as surfactant, polyethylene glycol 400 (PEG 400) as co surfactant and water as aqueous phase. The developed GC method was used to quantify the FA content in ME formulations. The results indicated that the developed GC method is very effective to quantify the FA content in the ME formulations. The antimicrobial efficacy of FA-based MEs were tested against Staphylococcus aureus. It was concluded that the FA-based MEs have strong antimicrobial effect against S. aureus