A comparative study of two different numerical schemes for the simulation of nonlinear dynamics of heated falling thin films

In this research, an attempt is made to characterise qualitatively the stability and dynamics of an inclined thin liquid film under the influence of instabilities due to thermo-capillarity and evaporative effects as well as van der Waals intermolecular forces, by employing the implicit finite difference method. The results are compared with solutions obtained by the Fourier spectral method. Flow in thin films of a Newtonian liquid on an inclined plane with an adjacent passive gas layer, is well represented by the Navier-Stokes equations, equation of continuity and associated boundary conditions. Long-wave (lubrication) approximation is applied to simplify the governing equations to arrive at a nonlinear partial differential equation, called equation of evolution (EOE). The spatio-temporal evolution of the interfacial instability in the film caused by internal and/or external effects are studied by numerically solving the EOE using the implicit finite difference method. The results of the numerical simulations of our thin film model are compared with those of a similar problem solved using Fourier spectral method from the literature. Simulations show remarkable agreement in the film dynamics predicted by these two methods. The film rupture times obtained using our implicit finite difference scheme closely match with the values obtained from the Fourier spectral method within less than 1% error. This implies that the implicit finite difference method can be satisfactorily employed for the efficient numerical simulation of the thin film flows, and to decipher its nonlinear dynamics reliably

Speak Pakistan: Challenges in Developing Pakistan Sign Language using Information Technology

Gesture based communication called Sign Language (SL) is the fundamental communication channel between hard of hearing individuals. Communication through signing is a visual motion dialect. Hard of hearing individuals use gesture based communication as their primary medium for correspondence. Different countries have their own sign language as the United States of America has American Sign Language (ASL), China has Chinese Sign Language (CSL), India has Indian Sign Language (ISL), and similarly Pakistan has Pakistan Sign Language (PSL). Most of the developed nations have addressed the issues of their hearing impaired people by launching projects involving Information Technology to reduce this gap between a deaf and a normal person. In central and south Asia, a considerable work has been conducted on ISL and CSL. However, Pakistan Sign Language is a linguistically under-investigated in the absence of any structured information about the language contents, grammar, and tools and services for communication. Hence, the major contributions of this research are to highlight the challenges to bridge this communication gap for Pakistani deaf community by using the existing literature, and to propose an Information Technology based architectural framework to identify major components to build applications which may help bridging the gap between the deaf and normal people of the country

Sustainable flame retardant treatment for cotton fabric using non formaldehyde cross linking agent

Most flame-retardant finishing agents have been found to have an adverse effect on our environment and human skin because of the carcinogenic chemicals in their structure. Pyrovatex CP New is an Organophosphorus based flame retardant (FR) agent widely used in FR treatment of combustible. However, the main problem related to it is the release of high formaldehyde content (a known carcinogen). When used with methylated melamine (MM) an effective cross-linker. The objective of this research was to use citric acid (CA) and its integration with sodium hypophosphite (NaH2PO2) and two different co-catalyst Titanium dioxide (TiO2) and phosphoric acid (PA) as a flame‐retardant finishing for cotton fabrics. The flammability of cotton fabric was assessed by a manual vertical flammability test, it is found that the combination of co-catalysts in FR formulation lowers the flammability of cotton. The pyrolysis characteristics and char residue yield of the treated cotton shows that the flame retardancy improves as the amount of catalyst is increased. The whiteness index, crease recovery and tensile strength of the treated cotton fabric was also significantly improved with our suggested recipe formulation. The finished cotton has significant variations in terms of its tensile strength, crease recovery, and whiteness index

LEARN: A multi-centre, cross-sectional evaluation of Urology teaching in UK medical schools

OBJECTIVE: To evaluate the status of UK undergraduate urology teaching against the British Association of Urological Surgeons (BAUS) Undergraduate Syllabus for Urology. Secondary objectives included evaluating the type and quantity of teaching provided, the reported performance rate of General Medical Council (GMC)-mandated urological procedures, and the proportion of undergraduates considering urology as a career. MATERIALS AND METHODS: LEARN was a national multicentre cross-sectional study. Year 2 to Year 5 medical students and FY1 doctors were invited to complete a survey between 3rd October and 20th December 2020, retrospectively assessing the urology teaching received to date. Results are reported according to the Checklist for Reporting Results of Internet E-Surveys (CHERRIES). RESULTS: 7,063/8,346 (84.6%) responses from all 39 UK medical schools were included; 1,127/7,063 (16.0%) were from Foundation Year (FY) 1 doctors, who reported that the most frequently taught topics in undergraduate training were on urinary tract infection (96.5%), acute kidney injury (95.9%) and haematuria (94.4%). The most infrequently taught topics were male urinary incontinence (59.4%), male infertility (52.4%) and erectile dysfunction (43.8%). Male and female catheterisation on patients as undergraduates was performed by 92.1% and 73.0% of FY1 doctors respectively, and 16.9% had considered a career in urology. Theory based teaching was mainly prevalent in the early years of medical school, with clinical skills teaching, and clinical placements in the later years of medical school. 20.1% of FY1 doctors reported no undergraduate clinical attachment in urology. CONCLUSION: LEARN is the largest ever evaluation of undergraduate urology teaching. In the UK, teaching seemed satisfactory as evaluated by the BAUS undergraduate syllabus. However, many students report having no clinical attachments in Urology and some newly qualified doctors report never having inserted a catheter, which is a GMC mandated requirement. We recommend a greater emphasis on undergraduate clinical exposure to urology and stricter adherence to GMC mandated procedures

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Nonlinear dynamics of heated falling films under the influence of long-range Van Der Walls intermolecular force interactions

Thin liquid film flowing on an inclined plane and subjected to various physico-chemical effects such as thermocapillarity, solutal-Marangoni and evaporative instabilities at the film surface and subjected to van der Waals intermolecular interaction forces, has been numerically simulated using explicit and implicit finite difference methods. There are several works published on flow of thin liquid films employing various flow configurations of thin film such as thin film on plane, inclined, and wavy surfaces over the past years. Thin film flow on inclined surface compared to on a horizontal surface, also experiences the gravity force which may play substantial role in the nonlinear dynamics of the film coupled with other forces. In this research, we attempt to update our previous study of the stability and dynamics of thin liquid films subjected to thermocapillary and evaporative instabilities at the free surface by including additional instabilities owing to long range van der Waals force in the film model. Similar to the previous studies cited in the literature (Joo et al., 1991; Hamza, 2017), for a Newtonian liquid, flow in thin liquid film on an inclined support and bounded by a passive gas, is represented by Navier-Stokes equation, equation of continuity and appropriate boundary conditions. The external effects are incorporated in the body force term of the Navier-Stokes equation. Following the procedure as outlined in the literature these governing equations are simplified followinga long-wave asymptotic analysis to derive a nonlinear fourth order partial differential equation, henceforth referred to as equation of evolution (EOE), which describes the temporal and spatial evolution of the interfacial instability in the film caused by complex nonlinear interactions of internal and/or external forces. We carried out extensive numerical simulations for various combinations of thin film flow parameters representative of different physical flow situations encountered in practice. Especially the effect of van der Waals forces on the film morphology and breakup is investigated at depth. This clearly shows that van der Walls forces though insignificant in thick films (proportional to h-6, where h is the film thickness) assumes significant role at short distances imparting catastrophic effect on the film instability as thin film approached breakup point. Here we present the results of our numerical simulation as an attempt to decipher the complex nonlinear dynamics of thin film flows especially delineating the role of van der Waals interaction forces in combination with other antagonistic physico-chemical effects

Numerical simulation of non-isothermal thin liquid film flow on inclined plane using an implicit finite difference scheme

The classical problem of the stability and dynamics of thin liquid films on solid surfaces has been studied extensively. Particularly, thin liquid films subjected to various physico-chemical effects such as thermocapillarity, solutal-Marangoni and evaporative instabilities at the film surface has been the focus of research for more than two decades. Various flow configurations of thin film such as thin film on plane, inclined, and wavy surfaces has been the subject of recent investigations. An inclined film compared to a horizontal film, also experiences the gravity force which may significantly influence the nonlinear dynamics of the film coupled with other forces. In this research, we attempt to study the stability and dynamics of thin liquid films subjected to thermocapillarity and evaporative instabilities at the free surface besides instability owing to ubiquitous van der Waals attraction, using numerical simulations. For a Newtonian liquid, flow in thin liquid film on a planar support and bounded by a passive gas, is represented by Navier-Stokes equation, equation of continuity and appropriate boundary conditions. The external effects are incorporated in the body force term of the Navier-Stokes equation. These governing equations are simplified using the so called long-wave approximation to arrive at a nonlinear partial differential equation, henceforth called equation of evolution (EOE), which describes the time evolution of the interfacial instability in the film caused by internal and/or external effects. Efficient numerical method is required for the solution of the equation of evolution (EOE) in order to comprehend the nonlinear dynamics of the thin film. Here we present the results of our numerical simulation using Crank-Nicholson implicit finite difference scheme applied to the thin film model incorporating instabilities owing to gravity, evaporation and thermo-capillarity. Comparison of our results with those obtained from Spectral method, show remarkable agreement for most of the cases investigated

Instabilities in non-isothermal falling thin film flows

The stability and dynamics of thin liquid films subjected to van der Waals attraction, thermocapillarity and evaporative instabilities at the free surface, is studied using numerical simulations. For a Newtonian liquid, flow in thin liquid film on a solid support and bounded by a passive gas is represented by Navier-Stokes equation, equation of continuity and appropriate boundary conditions. The external effects are generally incorporated in the body force term of the Navier-Stokes equation. These governing equations can then be simplified using so called long-wave approximation to arrive at a nonlinear partial differential equation, henceforth called equation of evolution (EOE), which describes the time evolution of the interfacial instability caused by internal and/or external effects [1-3]. The comprehensive characterization of the nonlinear dynamics and surface morphology of thin-film requires efficient numerical method for the solution of the equation of evolution (EOE). Our thin-film flow configuration has been numerically simulated using a fully explicit finite difference formulation as well as an implicit finite difference scheme. The explicit finite difference scheme seems to replicate the solution from spectral method as well as implicit scheme to a high degree of conformity for most of the cases investigated. Thus explicit scheme presented here is a relatively simple numerical scheme with much less computational expense compared to Fourier spectral and implicit Crank Nicholson schemes for the full scale simulation of the various thin film models. However, the detailed numerical simulation of the thin film problem is being investigated

Contributions and Challenges of High Throughput qPCR for Determining Antimicrobial Resistance in the Environment: A Critical Review

Expansion in whole genome sequencing and subsequent increase in antibiotic resistance targets have paved the way of high throughput qPCR (HT-qPCR) for analyzing hundreds of antimicrobial resistance genes (ARGs) in a single run. A meta-analysis of 51 selected studies is performed to evaluate ARGs abundance trends over the last 7 years. WaferGenTM SmartChip is found to be the most widely used HT-qPCR platform among others for evaluating ARGs. Up till now around 1000 environmental samples (excluding biological replicates) from different parts of the world have been analyzed on HT-qPCR. Calculated detection frequency and normalized ARGs abundance (ARGs/16S rRNA gene) reported in gut microbiome studies have shown a trend of low ARGs as compared to other environmental matrices. Disparities in the HT-qPCR data analysis which are causing difficulties to researchers in precise interpretation of results have been highlighted and a possible way forward for resolving them is also suggested. The potential of other amplification technologies and point of care or field deployable devices for analyzing ARGs have also been discussed in the review. Our review has focused on updated information regarding the role, current status and future perspectives of HT-qPCR in the field of antimicrobial resistance

Bim-based energy analysis and optimization using insight 360 (case study)

Building information modeling (BIM) is a modern data information platform and management tool that promotes the development of green buildings. In Pakistan, the building sector consumes more than 50 % of total energy consumption and it is growing at annual rates of 4.7 % and 2.5 % in household and commercial sectors, respectively. The energy problem is the biggest single economic drag on Pakistan, the Pakistan BIM Council (PBC) is attempting to implement BIM adoption in the construction industry. Using Autodesk Insight 360 and Green Building Studio, an energy analysis and optimization case study of A-Block COMSATS Abbottabad, Pakistan is chosen. This study explores the energy performance of an academic building as a case study in order to optimize energy use by rotating the building 360 degrees at 45-degree intervals and utilizing BIM to install energy-efficient construction materials. Existing academic buildings have lower energy use and annual cost savings. The annual energy and financial savings are 585.10 kWh and 550 $, respectively. Applying factors to energy analysis can result in improved conceptual design with good environmental effectiveness, thus assisting in the pursuit of environmental sustainability