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Model based simulation and genetic algorithm based optimisation of spiral wound membrane RO process for improved dimethylphenol rejection from wastewater
Get PDFYesReverse Osmosis (RO) has already proved its worth as an efficient treatment method in chemical and environmental engineering applications. Various successful RO attempts for the rejection of organic and highly toxic pollutants from wastewater can be found in the literature over the last decade. Dimethylphenol is classified as a high-toxic organic compound found ubiquitously in wastewater. It poses a real threat to humans and the environment even at low concentration. In this paper, a model based framework was developed for the simulation and optimisation of RO process for the removal of dimethylphenol from wastewater. We incorporated our earlier developed and validated process model into the Species Conserving Genetic Algorithm (SCGA) based optimisation framework to optimise the design and operational parameters of the process. To provide a deeper insight of the process to the readers, the influences of membrane design parameters on dimethylphenol rejection, water recovery rate and the level of specific energy consumption of the process for two different sets of operating conditions are presented first which were achieved via simulation. The membrane parameters taken into consideration include membrane length, width and feed channel height. Finally, a multi-objective function is presented to optimise the membrane design parameters, dimethylphenol rejection and required energy consumption. Simulation results affirmed insignificant and significant impacts of membrane length and width on dimethylphenol rejection and specific energy consumption, respectively. However, these performance indicators are negatively influenced due to increasing the feed channel height. On the other hand, optimisation results generated an optimum removal of dimethylphenol at reduced specific energy consumption for a wide sets of inlet conditions. More importantly, the dimethylphenol rejection increased by around 2.51% to 98.72% compared to ordinary RO module measurements with a saving of around 20.6% of specific energy consumption
Effects of materials positioning and tool rotational speed on metallurgical and mechanical properties of dissimilar modified friction stir clinching of AA5754-O and AA2024-T3 sheets
Get PDFYesThe performance of the modified friction stir clinched and friction stir spot welded joints of AA5754-O and AA2024-T3 Al alloy was improved by investigating the impact of material flow influencing parameters such as material positioning and tool rotational speed on the microstructure, mechanical and fracture behaviors of the joints. The results reveal that the positioning of a harder material (AA2024-T3) as the upper plate induces higher peak temperatures in the friction stir clinched (500 °C) and friction stir spot welded (475 °C) joints. This positioning favors inter-material mingling, grain coarsening with inherent higher dislocation density and tangles, and improved tensile failure loads in the AA2024-T3/AA5754-O joint than the AA5754-O/AA2024-T3 joint. The formation of partial weld-center defect declines in the AA2024-T3/AA5754-O at low tool rotational speed due to the better local heat build-up and geometric-differential flow effect in comparison with the AA5754-O/AA2024-T3 counterparts. The positioning of harder Al alloy on the top of a soft Al alloy is thus recommended for the improvement of modified friction stir clinched joints
Understanding Customer Experience and Its Mediating Roles in Human-Chatbot Interaction
Get PDFThe advancement of artificial intelligence and its diverse applications
have attracted great interests from several research scholars examining
communication between humans and chatbots. Many have explained the
motivations of chatbot use, however, less emphasis has been given to myriad
customer experiential needs for the interaction with this AI-powered technology.
Therefore, in the light of U&G theory, this thesis presents a conceptual
framework for customer experience as the needs for chatbot use. SOR model
was also adopted to establish the links among customer experience as
organisms (utilitarian – perceived informativeness and credibility; hedonic –
perceived transparency, enjoyment and engagement; anthropomorphism –
mindful and mindless anthropomorphism; and social presence), their primary
stimuli (functionality, communication style similarity and aesthetics) and
responses (customer satisfaction and reuse intention). 417 convenient samples
were collected from the UK where chatbots are widely used. Results from SEM revealed that perceived credibility, informativeness, enjoyment, functionality and
communication style similarity hold the keys for customer satisfaction, while
effects of anthropomorphism and social presence are not significant in this
research setting. This study has enriched U&G theory by addressing customer
experience as ones’ motivations to use chatbots. Also, it has presented a fresh understanding of customer experience in chatbot context by considering
utilitarian, hedonic, anthropomorphism and social presence as dimensions of
customer experience rather than merely measuring how customers think, feel,
sense, act and relate. In addition, practical implications and direction for future
research are discussed
Germ cell determination and the developmental origin of germ cell tumors
Get PDFYesIn each generation, the germline is tasked with producing somatic lineages that form the body, and segregating a population of cells for gametogenesis. During animal development, when do cells of the germline irreversibly commit to producing gametes? Integrating findings from diverse species, we conclude that the final commitment of the germline to gametogenesis - the process of germ cell determination - occurs after primordial germ cells (PGCs) colonize the gonads. Combining this understanding with medical findings, we present a model whereby germ cell tumors arise from cells that failed to undertake germ cell determination, regardless of their having colonized the gonads. We propose that the diversity of cell types present in these tumors reflects the broad developmental potential of migratory PGCs.This work was supported by the Howard Hughes Medical Institute where D.C.P. is an Investigator, and the Frontier Research Program from the Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology. P.K.N. is a recipient of the Hope Funds for Cancer Research Fellowship (HFCR-15-06-06) and an Early Career Fellowship from the National Health and Medical Research Council, Australia (GNT1053776)
Suppressor of cytokine signalling 3 (SOCS3) turnover and regulation of human saphenous vein smooth muscle cell signalling and function
Get PDFNeointimal hyperplasia (NIH) is a cardiovascular disease characterised by increased smooth muscle cell (SMC) inflammation and proliferation. Suppressor of cytokine signalling 3 (SOCS3) limits Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathways involved in vascular remodelling but is limited by its short biological half-life. Therefore, mutation of all 9 Lys residues that are potential sites of ubiquitylation to Arg should produce a mutated SOCS3 resistant to ubiquitin-mediated proteasomal degradation (“Lys-less” SOCS3). This study hypothesise that enhancing SOCS3 stability and limiting JAK/STAT signalling may provide sustained inhibition of the vascular remodelling in NIH.
Lentiviral transduction of WT and Lys-less SOCS3 in human saphenous vein (HSVSMCs) was highly efficient after 48 hours (>97%) and was sustained over 2 weeks. Lys-less SOCS3 was resistant to ubiquitylation contrary to WT-transduced HSVECs, and Lys-less SOCS3 was more stable (t1/2=4h) than WT (t1/2<4h) (n=6, P<0.001) in HSVSMCs. In HSVSMCs, both Lys-less SOCS3 and WT inhibited sIL-6Rα/IL-6 mediated STAT3 activation but not extracellular signal regulated protein kinase 1/2 (ERK1/2) by 80±7% (Lys-lessSOCS3/pSTAT3) and 74±6% (WT/pSTAT3) (n=3, P<0.05) and similarly inhibited PDGF-mediated STAT3 activation but not ERK1/2 by 67±17% (Lys-less SOCS3/pSTAT3) and 72±18% (WT/pSTAT3) (n=3, P<0.05). Functionally, Lys-less SOCS3 and WT were equivalent in inhibiting sIL-6Rα/IL-6 and PDGF-induced proliferation, whilst having no effects on PDGF-induced migration in HSVSMCs.
Lys-less SOCS3 can be successfully transduced into primary HSVSMCs. It is more stable than WT yet retains its functional ability to ameliorate pro-inflammatory signalling and SMC proliferation, making it an attractive option for developing treatment of NIH.University of Botswan
Turbulence structure and momentum exchange in compound channel flows with shore ice covered on the floodplains
Get PDFYesIce cover formed on a river surface is a common natural phenomenon during winter season in cold high latitude northern regions. For the ice-covered river with compound cross-section, the interaction of the turbulence caused by the ice cover and the channel bed bottom affects the transverse mass and momentum exchange between the main channel and floodplains. In this study, laboratory experiments are performed to investigate the turbulent flow of a compound channel with shore ice covered on the floodplains. Results show that the shore ice resistance restricts the development of the water flow and creates a relatively strong shear layer near the edge of the ice-covered floodplain. The mean streamwise velocity in the main channel and on the ice-covered floodplains shows an opposite variation pattern along with the longitudinal distance and finally reaches the longitudinal uniformity. The mixing layer bounded by the velocity inflection point consists of two layers that evolve downstream to their respective fully developed states. The velocity inflection point and strong transverse shear near the interface in the fully developed profile generate the Kelvin-Helmholtz instability and horizontal coherent vortices. These coherent vortices induce quasi-periodic velocity oscillations, while the dominant frequency of the vortical energy is determined through the power spectral analysis. Subsequently, quadrant analysis is used in ascertaining the mechanism for the lateral momentum exchange, which exhibits the governing contributions of sweeps and ejections within the vortex center. Finally, an eddy viscosity model is presented to investigate the transverse momentum exchange. The presented model is well validated through comparison with measurements, whereas the constants α and β appeared in the model need to be further investigated.National Natural Science Foundation of China (NSFC). Grant Numbers: 52020105006, 11872285: State Key Laboratory of Water Resources and Hydropower Engineering Science (WRHES), Wuhan University. Grant Number: 2018HLG0
A role for Rad5 in ribonucleoside monophosphate (rNMP) tolerance
Get PDFYesRibonucleoside monophosphate (rNMP) incorporation in genomic DNA poses a significant threat to genomic integrity. In addition to repair, DNA damage tolerance mechanisms ensure replication progression upon encountering unrepaired lesions. One player in the tolerance mechanism is Rad5, which is an E3 ubiquitin ligase and helicase. Here, we report a new role for yeast Rad5 in tolerating rNMP incorporation, in the absence of the bona fide ribonucleotide excision repair pathway via RNase H2. This role of Rad5 is further highlighted after replication stress induced by hydroxyurea or by increasing rNMP genomic burden using a mutant DNA polymerase (Pol ε - Pol2-M644G). We further demonstrate the importance of the ATPase and ubiquitin ligase domains of Rad5 in rNMP tolerance. These findings suggest a similar role for the human Rad5 homologues helicase-like transcription factor (HLTF) and SNF2 Histone Linker PHD RING Helicase (SHPRH) in rNMP tolerance, which may impact the response of cancer cells to replication stress-inducing therapeutics
What were the effects of the post-colonial experience of counterinsurgency on UK forces in southern Iraq? Were the lessons absorbed and implemented?
Get PDFThis thesis examines the British army and its legacy of counterinsurgency from the 20th century.
It analyses the effects of post-colonial counterinsurgency and the army’s ability to learn from
previous counterinsurgency conflicts to create new doctrine from earlier examples that could
have had lessons for the UK forces in southern Iraq.
Doctrine (both official and unofficial) ranges from endorsed army field manuals to
theory written by experts while on defence fellowships. The army’s ability to create
new doctrine from previous campaigns lessons and how it is diffused across the armed
forces is also assessed.
The conflicts used as post-colonial counterinsurgencies scrutinise Oman and Northern
Ireland. These two case studies provide mixed lessons, that should advance and
expand British counterinsurgency theory and models. The previous historical
occurrences of counterinsurgency have created a British approach which has
established a four-pillar framework which encompasses minimum force, civil-military
co-operation, use of intelligence and tactical flexibility. This approach could identify lessons for a modern British army deployed to Iraq.
If lessons and previous outcomes are analysed to create new doctrine, strategy and
tactics that encompass the four pillars framework, what went wrong in southern Iraq?
Could lessons from earlier campaigns have assisted British efforts
Breast cancer, medical imaging, and cancer genetics. A new genetic concept regarding the causes and prevention strategies of cancer is presented
Get PDFBreast cancer is the most common cancer type in the United Kingdom. Many women with breast cancer do not show any noticeable symptoms in their early stages, hence regular breast screening is important. In this research focus is on medical imaging and its role in breast cancer screening, diagnosis, and treatment monitoring. Around 10% of all cancers are caused by inherited gene mutations which may cause cancer to run in families. Though, majority of cancer cases (up to 90%) are caused by acquired gene mutations which may also appear to run in families when family members share a particular environment or exposure. Genetic testing is conducted in this research on a number of participants to investigate the cancer cases found among their families. The findings of this research show that significant improvements have taken place in the emergence of hybrid imaging modalities used for breast imaging, through the fusion of different imaging techniques. The findings also provide evidence that similar to cancers caused by inherited gene mutations, cancers caused by non-inherited gene mutations may also appear to run in families when family members share certain environments and exposures or lifestyle behaviours. As a result, a new genetic concept of cancer essential to understand and control the disease is presented in this work which links between the human population origins and migrations, environmental factors and gene mutations, and the development of cancer. Furthermore, a number of cancer prevention strategies are recommended in this study to prevent people from getting the disease
The role of the diagnostic radiographer in child safeguarding: Implications for education and practice. A multimethod exploration comprising quantitative and qualitative approaches to identify how diagnostic radiographers can contribute towards child safeguarding in an evolving clinical environment
Get PDFBackground- Diagnostic radiography is an established method of investigating child safeguarding concerns. The role of the radiographer in identifying signs that represent safeguarding concerns and acting as a conduit between the patient and other professionals is less well understood.
Aims- To evaluate the role of the radiographer in child safeguarding. Establish the contributory factors that influence that role and identify the measures that can be taken to maximise the contribution that could be made to protect patients.
Methods- A multimethod approach of two studies (KAP survey and semi-structured interviews) was implemented sequentially to permit the second study to be influenced by the results of the first.
Results - An inconsistent knowledge base in terms of child safeguarding exists. A positive attitude towards the profession’s role was identified and an inference that the profession does contribute to the escalation process, albeit only exceptionally.
Conclusion- Those in the earlier stages of their career are most in need of recognising suspicious appearances. Radiographic appearances are commensurate with the modality utilised and needs accounting for within education. Contemporary practice makes assessment of more abstract appearances of child safeguarding concerns challenging. The systems of escalating concerns are known, and the profession is willing and able to contribute.
Recommendations- Educational focus on the recognition of pathognomonic signs of abuse and aetiology to permit recognition of occasions when injury and clinical history disagree. Education should also include child safeguarding concerns commensurate with the modality utilised and as part of image reporting. Further research is needed to promote the role of the profession and to evaluate the impact of technological advancement on the profession’s capability to contribute effectively