Fabrication of Polyvinylidene Fluoride Hollow Fiber Membranes for Membrane Distillation

Desalination technologies can help humanity tap into the most abundant source of water on earth, seawater; however, desalination is an energy-demanding process. Most of the desalination plants worldwide use conventional energy resources; therefore, desalination leaves a large carbon footprint. Solar energy is an available source of energy that can be harvested and integrated into desalination systems. Membrane distillation (MD) is an emerging purification technology that many offers many advantages over traditional desalination systems. For starters, it can utilize low-grade thermal energy to drive the separation, therefore, it can be suitably integrated into the solar-thermal energy scheme. Additionally, MD can be used to desalinate challenging water streams with minimal pretreatment, which makes it a suitable candidate for off-grid desalination in rural regions. Herein, the lack of proper membranes and designed modules, membrane wetting and fouling, and the thermodynamic inefficiency in this system were identified as the bottleneck of the MD process, and novel solutions to tackle challenges were investigated. Polyvinylidene fluoride (PVDF) membranes suitable for MD were fabricated using nonsolvent induced phase separation (NIPS). The membranes were fully characterized to gain insight into the characteristics of MD membranes. By adjusting the parameters controlling NIPS, membrane characteristics such as porosity, thickness, geometry, surface topography, and gas permeability were controlled. The desalination performance of the membranes, as well as their fouling and wetting propensity, were evaluated and studied. Some post-processing methods were employed on the membranes to hinder their fouling and wetting tendencies in MD operation. The membranes that were fabricated in this study displayed robust performance in challenging water streams

Fabrication of Polyvinylidene Fluoride Hollow Fiber Membranes for Membrane Distillation

Desalination technologies can help humanity tap into the most abundant source of water on earth, seawater; however, desalination is an energy-demanding process. Most of the desalination plants worldwide use conventional energy resources; therefore, desalination leaves a large carbon footprint. Solar energy is an available source of energy that can be harvested and integrated into desalination systems. Membrane distillation (MD) is an emerging purification technology that many offers many advantages over traditional desalination systems. For starters, it can utilize low-grade thermal energy to drive the separation, therefore, it can be suitably integrated into the solar-thermal energy scheme. Additionally, MD can be used to desalinate challenging water streams with minimal pretreatment, which makes it a suitable candidate for off-grid desalination in rural regions. Herein, the lack of proper membranes and designed modules, membrane wetting and fouling, and the thermodynamic inefficiency in this system were identified as the bottleneck of the MD process, and novel solutions to tackle challenges were investigated. Polyvinylidene fluoride (PVDF) membranes suitable for MD were fabricated using nonsolvent induced phase separation (NIPS). The membranes were fully characterized to gain insight into the characteristics of MD membranes. By adjusting the parameters controlling NIPS, membrane characteristics such as porosity, thickness, geometry, surface topography, and gas permeability were controlled. The desalination performance of the membranes, as well as their fouling and wetting propensity, were evaluated and studied. Some post-processing methods were employed on the membranes to hinder their fouling and wetting tendencies in MD operation. The membranes that were fabricated in this study displayed robust performance in challenging water streams

High pressure polymer science, routes to drug delivery

The area of high pressure is receiving great attention and being used to study a range of materials including metals, minerals, energetic materials and pharmaceuticals. Polymers are being increasingly used in pharmaceutical and biomedical applications. The main reason behind this is their physico-chemical characteristics that can be tuned to suit different applications. These characteristics can differ in different forms of the same compound. These forms can be obtained by different techniques including high pressure (Chapter 1).;The work presented in this thesis has used high pressure techniques, including diamond anvil cells (DACs) and large volume press cell, to investigate pharmaceutical polymers and a model active pharmaceutical ingredient (ibuprofen). The change of materials under pressure was studied by in-situ Raman spectroscopy (Chapter 2). The first challenge faced in this project was fluorescence, which hinders Raman spectroscopy.;Surface enhanced Raman spectroscopy (SERS) technique was adopted to improve the signal and overcome fluorescence. This was achieved successfully on weak Raman scattering amino acids and fluorescent polymers (Chapter 3). A range of commonly used polymers were studied under high pressure in DAC. Poly glycolic acid (PGA) and poly lactic acid (PLA) exhibited a similar phenomenon of moving from crystalline or semi-crystalline into a less ordered form between 4-5 GPa. Ethylcellulose (EC) and hydroxypropyl methylcellulose (HPMC) demonstrated a similar change at about 2-3 GPa (Chapter 4).;Both EC and HPMC were used as a platform for sustained release dosage forms in different ratios with ibuprofen. These formulations were mixed using resonant acoustic mixing technique and subjected to high pressure (0.8 GPa) before being tested for drug release. The change in release patterns was mainly caused by the pressure transmitting medium (PTM) rather than the application of pressure (Chapter 5). Individual formulation components were used as received powders, treated by PTM at ambient pressure and subjected to 0.8 GPa before exploring their flowability.;The PTM treatment and pressure has increased the flow function of polymers but not ibuprofen. The formulation blends were tested for flowability in powder and ambient pressure forms. Unlike individual components, the treated blends exhibited a decrease in flow function and increase in cohesion (Chapter 6).;Overall, this thesis demonstrates that the application of pressure, using DACs, on commonly used polymers in pharmaceutical applications does help in inducing phase transitions at different pressures. Adapting SERS technique has been successful in overcoming fluorescence in polymers and improving Raman signal in weakly scattering amino acids. The application of pressure, using large volume press, did not have a significant effect on release pattern of APIs from the tested formulations.;The change was mainly due to the pressure transmitting medium. The effect of pressure was tested on powder flowability and found to increase polymers flowability but not ibuprofen.The area of high pressure is receiving great attention and being used to study a range of materials including metals, minerals, energetic materials and pharmaceuticals. Polymers are being increasingly used in pharmaceutical and biomedical applications. The main reason behind this is their physico-chemical characteristics that can be tuned to suit different applications. These characteristics can differ in different forms of the same compound. These forms can be obtained by different techniques including high pressure (Chapter 1).;The work presented in this thesis has used high pressure techniques, including diamond anvil cells (DACs) and large volume press cell, to investigate pharmaceutical polymers and a model active pharmaceutical ingredient (ibuprofen). The change of materials under pressure was studied by in-situ Raman spectroscopy (Chapter 2). The first challenge faced in this project was fluorescence, which hinders Raman spectroscopy.;Surface enhanced Raman spectroscopy (SERS) technique was adopted to improve the signal and overcome fluorescence. This was achieved successfully on weak Raman scattering amino acids and fluorescent polymers (Chapter 3). A range of commonly used polymers were studied under high pressure in DAC. Poly glycolic acid (PGA) and poly lactic acid (PLA) exhibited a similar phenomenon of moving from crystalline or semi-crystalline into a less ordered form between 4-5 GPa. Ethylcellulose (EC) and hydroxypropyl methylcellulose (HPMC) demonstrated a similar change at about 2-3 GPa (Chapter 4).;Both EC and HPMC were used as a platform for sustained release dosage forms in different ratios with ibuprofen. These formulations were mixed using resonant acoustic mixing technique and subjected to high pressure (0.8 GPa) before being tested for drug release. The change in release patterns was mainly caused by the pressure transmitting medium (PTM) rather than the application of pressure (Chapter 5). Individual formulation components were used as received powders, treated by PTM at ambient pressure and subjected to 0.8 GPa before exploring their flowability.;The PTM treatment and pressure has increased the flow function of polymers but not ibuprofen. The formulation blends were tested for flowability in powder and ambient pressure forms. Unlike individual components, the treated blends exhibited a decrease in flow function and increase in cohesion (Chapter 6).;Overall, this thesis demonstrates that the application of pressure, using DACs, on commonly used polymers in pharmaceutical applications does help in inducing phase transitions at different pressures. Adapting SERS technique has been successful in overcoming fluorescence in polymers and improving Raman signal in weakly scattering amino acids. The application of pressure, using large volume press, did not have a significant effect on release pattern of APIs from the tested formulations.;The change was mainly due to the pressure transmitting medium. The effect of pressure was tested on powder flowability and found to increase polymers flowability but not ibuprofen

Effectiveness of Learning with 3D-Lab on Omani Basic Education Students' Achievement, Attitudes and Scientific Thinking

This paper aims to measure the effectiveness of the 3DL on Omani students' acquisition of practical abilities and skills. It examines the effectiveness of the 3D-lab in science education and scientific thinking acquisition as part of a national project funded by The Research Council. Four research tools in a Pre-Post Test Control Group Design, findings show statistically significant differences in student achievement in favor of the experimental group. The results show students' attitudes are positive towards using 3D-lab in teaching. Improvements in logical and visual thinking are also observed. The paper then draws conclusions and recommendations

Analysing the Impact Factors of Customer Loyalty Among Small and Medium-Sized Hotels (Smshs) in Dubai

Purpose: This study aims to identify the most important characteristics that contribute to customer loyalty in the hotel sector, specifically in Dubai's hotels.   Theoretical framework:   Small and medium-sized hotels (SMSHs) were examined from the standpoint of their customers using customer loyalty as a performance metric. This research will shed additional light on how customer satisfaction and trust in  SMSHs contribute to customer loyalty, particularly within Dubai's hotel sector SMSHs.   Design/methodology/approach: A quantitative study involves the use of statistical analysis and numerical data to test hypotheses and draw conclusions about the relationships between variables based on a sample of 372 respondents from SMSHs in Dubai.   Findings: The findings showed a positive and significant relationship between customer trust, service quality, customer satisfaction and customer loyalty in the SMSHs in Dubai. Also, customer satisfaction mediates the relationship between customer trust and customer loyalty, and customer satisfaction mediates the relationship between customer trust and customer loyalty in the SMSHs in Dubai.   Research, Practical & Social implications:  To boost client satisfaction, hotels should undertake a more detailed service assessment of online hotel performance and improve the hotel's application system, which is prone to faults, by speeding up digital technology.   Originality/value:  An original study on small and medium-sized hotels in Dubai would provide valuable insights into the unique challenges and opportunities faced by this segment of the hospitality industry in a highly competitive and dynamic market

The Level of Psychological Well Being and Its Relationship to Gratitude Among Mutah University Students Who Changed Their Majors

The study aimed to identify the level of psychological well-being and its association with gratitude among Mutah university students who changed their majors. The sample of the study consisted of (266) male and female students. To achieve the objectives of the study, two scales were developed namely, the psychological wellbeing scale and the Gratitude Scale.  The validity and reliability of the scales were verified. The results indicated that: A) the level of psychological well being and gratitude among the students of Mutah University was moderate; B) there was a positive and acceptable relationship between these two variables; C) male students were more grateful than female students, and that the students in humanities colleges ( male and female ) were more grateful than students in scientific colleges and D) gratitude contributes in an acceptable way to shaping the level psychological wellbeing. The study recommended directing high school students and their families to choose university majors that fit the preferences and abilities of these students, and which is demanded by the labor market. Keywords: Psychological wellbeing, Gratitude, Students who changed their majors. DOI: 10.7176/JEP/12-6-12 Publication date: February 28th 202

The Effect of Human Resources Practices on Sport Organization’s Performance in Oman: The Mediating Role of Leadership Style

Purpose: This paper examines the impact of human resource management (HRM) practices on organizational performance, with mediating role of leadership style.   Theoretical framework: This study integrates theoretical perspectives on HRM practices Namely (the recruitment selection process, incentive system, and training & development), Leadership style and organisational performance. The conceptual model for this study was developed based on previous research in the field of HRM practices and leadership styles globally. The conceptual model has HRM practices as an independent variable (IV), Leadership style as a mediator and organisational performance as a dependent variable (DV).   Design/Methodology/Approach: A survey questionnaire instrument was employed to collect data from 156 employees working at sport organisations in Oman. SPSS was used for analysing the data, and Smart-PLS were used to test the proposed hypotheses.   Findings: The result revealed that human resource practices are significantly related to organisational performance. Also, leadership styles mediated the influence of HRM practises on organisational performance.   Research, practical & social implications: The finding of this study provides valuable insights into sport organisations in Oman can enhance their HRM practices to improve organisational performance and achieve their goals. Moreover, it has been recommended that organizations use a leadership style that enhances organizational performance. The results come from a cross-sectional study which was done at the convenience of the researcher. The results may not be generalized across the country. The application of the results to other organisations must be done with maximum care.   Originality/Value: This study adds to the literature on the effectiveness of HRM practices, Leadership style in enhancing organisational performance in a specific context namely the sport organisations in Oman. The study also highlights the mediating role of leadership style in the relationship between HRM practices and organisational performance

Managing Transformers Risk through Failure Codification

The fast development and expansion of any service organizations which followed by increases in the asset numbers that’s need to have a proper maintenance strategy which should be cost effective. The aim of any strategy is to have a plan that contribute to improve asset performance by reducing downtime of asset failures. The aim of this paper is to set plan that determine the processes of creating failure code that can create a library of failure modes with its consequences and risk. This allow service provider to quickly understand the problem and any action that can be taken which have already proven by failure mode effect analysis. Also it’s identify most of the functional failures that might happened in the critical asset in the OETC’s network. In this study the transformer asset class was taken into the consideration for full failure mood and fault tree analysis. Defining failure codes can give specific instructions to complete a task to reduce the main time to wait in any failure from the total main time to repair, and any smiler failure mode from other assets the corrective action will remain consistent. The selective processes of creating a failure code give the organization a more holistic view of transformers risk which will be used to improve maintenance strategy by integrate those codes into work order system like CMMS

Blalock-Taussig Shunt versus Ductal Stenting as Palliation for Duct-Dependent Pulmonary Circulation

Objectives: There is limited data published from outside North America and Europe comparing the outcomes of a modified Blalock-Taussig shunt (MBTS) and ductal stenting as the first palliative procedure for infants with duct-dependent pulmonary circulation. This study reports the National Heart Center’s, in Muscat, Oman, experience in comparing the outcomes of these 2 interventions. Methods: This retrospective study included all infants with duct-dependent pulmonary circulation who received either a MBTS or ductal stenting from 2016–2019. The primary outcomes were death or re-interventions. Secondary outcomes included death, subsequent re-interventions, survival to subsequent surgical intervention, survival to hospital discharge, post-procedural mechanical ventilation and duration of intensive care unit stay. Results: A total of 71 patients were included in the study, 33 (46%) of whom received ductal stenting. The prevalence of the primary outcome (death or re-intervention) in the patent ductus arteriosus (PDA) stent group was 54.5% versus 31.6% in the MBTS group but this was not statistically significant (P = 0.06). There was no difference between the 2 groups in terms of time to next surgical intervention (P = 0.233). The PDA stent group had shorter post-procedural, mechanical ventilation and intensive care unit stay durations (P <0.05). Syndromic patients were at higher risk of mortality compared to non-syndromic patients. Conclusion: MBTS and ductal stenting are both acceptable modalities as a palliative intervention for infants with duct-dependant pulmonary circulation. Syndromic patients are at higher risk of mortality. This can be considered an important factor for patient selection. Keywords: Blalock-Taussig Procedure; Patent Ductus Arteriosus; Pulmonary Atresia; Oman