87 research outputs found

    A Computational Approach to a Mathematical Model of Climate Change Using Heat Sources and Diffusion

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    The present work aims to extend the climate change energy balance models using a heat source. An ordinary differential equations (ODEs) model is extended to a partial differential equations (PDEs) model using the effects of diffusion over the spatial variable. In addition, numerical schemes are presented using the Taylor series expansions. For the climate change model in the form of ODEs, a comparison of the presented scheme is made with the existing Trapezoidal method. It is found that the presented scheme converges faster than the existing scheme. Also, the proposed scheme provides fewer errors than the existing scheme. The PDEs model is also solved with the presented scheme, and the results are displayed in the form of different graphs. The impact of the climate feedback parameter, the heat uptake parameter of the deep ocean, and the heat source parameter on global mean surface temperature and deep ocean temperature is also portrayed. In addition, these recently developed techniques exhibit a high level of predictability. Doi: 10.28991/CEJ-2022-08-07-04 Full Text: PD

    Numerical Schemes for Fractional Energy Balance Model of Climate Change with Diffusion Effects

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    This study aims to propose numerical schemes for fractional time discretization of partial differential equations (PDEs). The scheme is comprised of two stages. Using von Neumann stability analysis, we ensure the robustness of the scheme. The energy balance model for climate change is modified by adding source terms. The local stability analysis of the model is presented. Also, the fractional model in the form of PDEs with the effect of diffusion is given and solved by applying the proposed scheme. The proposed scheme is compared with the existing scheme, which shows a faster convergence of the presented scheme than the existing one. The effects of feedback, deep ocean heat uptake, and heat source parameters on global mean surface and deep ocean temperatures are displayed in graphs. The current study is cemented by the fact-based popular approximations of the surveys and modeling techniques, which have been the focus of several researchers for thousands of years.Mathematics Subject Classification:65P99, 86Axx, 35Fxx. Doi: 10.28991/ESJ-2023-07-03-011 Full Text: PD

    Macroeconomic Determinants of Urbanization in Pakistan

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    Urbanization refers to the migration of rural people to urban centers in search of better jobs. Urbanization and growth go together; no country has ever reached middle-income status without a significant population shift into cities. Urbanization has strong association with unemployment, economic growth, poverty, infrastructure, crimes, health, socio-economic conditions and education. In 2050, most of the urban population of the world will be concentrated in Asia (52%) and in Africa (21%). A simple and modest model provided reasonable results. Increase in literacy is a decisive factor that has significant impact on increasing urban population. Per capita GDP growth also positively influences the urban population. Age-structure is too an important determinant of migration and urbanization. It is an open secret that generally young persons have gone abroad. Specification and diagnostics test supported the model which reveals appropriateness and statistical soundness of the model. Serious heed is paid to delimitation of cities to make them manageable and governable. Agriculture is provided sufficient resources to discourage migration to cities

    A Third-order Two Stage Numerical Scheme and Neural Network Simulations for SEIR Epidemic Model: A Numerical Study

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    This study focuses on the cutting-edge field of epidemic modeling, providing a comprehensive investigation of a third-order two-stage numerical approach combined with neural network simulations for the SEIR (Susceptible-Exposed-Infectious-Removed) epidemic model. An explicit numerical scheme is proposed in this work for dealing with both linear and nonlinear boundary value problems. The scheme is built on two grid points, or two time levels, and is third-order. The main advantage of the scheme is its order of accuracy in two stages. Third-order precision is not only not provided by most existing explicit numerical approaches in two phases, but it also necessitates the computation of an additional derivative of the dependent variable. The proposed scheme's consistency and stability are also examined and presented. Nonlinear SEIR (susceptible-exposed-infected-recovered) models are used to implement the scheme. The scheme is compared with the non-standard finite difference and forward Euler methods that are already in use. The graph shows that the plan is more accurate than non-standard finite difference and forward Euler methods that are already in use. The solution obtained is then looked at through the lens of the neural network. The neural network is trained using an optimization approach known as the Levenberg-Marquardt backpropagation (LMB) algorithm. The mean square error across the total number of iterations, error histograms, and regression plots are the various graphs that can be created from this process. This work conducts thorough evaluations to not only identify the strengths and weaknesses of the suggested approach but also to examine its implications for public health intervention. The results of this study make a valuable contribution to the continuously developing field of epidemic modeling. They emphasize the importance of employing modern numerical techniques and machine learning algorithms to enhance our capacity to predict and effectively control infectious diseases. Doi: 10.28991/ESJ-2024-08-01-023 Full Text: PD

    Numerical modeling of mixed convective nanofluid flow with fractal stochastic heat and mass transfer using finite differences

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    This study presents the first comprehensive numerical simulation of heat and mass transfer in fractal-like mixed convective nanofluid flows. The flow of non-Newtonian nanofluids over flat and oscillating sheets is modelled mathematically, and a finite difference scheme is used to solve this model. The two-stage scheme can tackle fractal and fractal stochastic mathematical models of partial differential equations. The consistency in the mean square is proved, and Fourier series stability analysis is adopted to find stability conditions for fractal stochastic partial differential equation. The scheme is applied to solve the unsteady Casson nanofluid flow over the flat and oscillatory sheet, which affects thermal radiation, heat source, and chemical reaction. The existence of the solution is also provided for the Navier-Stokes equation of the considered flow model using fractal time derivative. The graph illustrates that the proposed fractal technique achieves faster convergence than the Crank-Nicolson approach. Applications in energy systems, materials science, and environmental engineering are just a few of the domains that could benefit from a better understanding of mixed convective nanofluid flows with fractal features, and that is what this research study hopes to accomplish. Scientists and engineers may better develop efficient and environmentally friendly systems by simulating and analyzing these complicated processes with the suggested finite difference technique

    1,3-Bis(1-cyclo­hexyl­eth­yl)imidazolidine-2-thione

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    The complete mol­ecule of the title compound, C19H34N2S, is generated by crystallographic twofold symmetry, with the C=S group lying on the rotation axis. A short C—H⋯S contact occurs in the mol­ecule. The five-membered ring is twisted and the cyclo­hexyl ring adopts a chair conformation. The dihedral angle between the mean plane of the five-membered ring and the basal plane of the cyclo­hexyl ring is 75.32 (13)°

    Impact of PUBG Game Addiction on Social Isolation and Narcissistic Tendencies among Gamers

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    The current research aimed to explore the relationship of PUBG game addiction with narcissistic tendencies and social isolation in gamers. For this correlation survey based research the data was conveniently collected from PUBG gamers (N= 101) age ranging from 13-30 years through online response method. The instruments included Online Game Addiction Scale (Kim, Namkoong, Ku, & Kim, 2008) Narcissistic Personality Inventory (Raskin & Hall, 1981) and Measures of Social Isolation (Zavaleta, Samuel, & Mills, 2017) for testing the hypothesis. According to the yielded results, an excellent reliability of these measures was established. The results also indicated that online game addiction, social isolation and narcissistic tendencies among PUBG game players are negatively correlated (<.05). It was concluded that online games do carry positive aspects of enhancing social skills and interactions among the players, while helping them exhibit behaviors and emotions that are not coherent with narcissistic tendencies. This paper also carries implications for families, friends, teachers and therapists of online gamers, who may use the findings to understand some of the positive aspects of playing online games

    Effectiveness of clean intermittent self catheterization in patients with recurrent urethral stricture post visual internal urethrotomy

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    OBJECTIVE :   Objective of the study is to determine the effectiveness of CISC in management of recurrent urethral strictures after visual internal urethrotomy.  METHODOLOGY :  This study   performed in department of urology   Saidu teaching hospital Swat  from June 2016 to July 2019 on 215 patients who were diagnosed as having urethral stricture disease. Patients were counseled  for CISC after removal of catheter 2 times a day for 8 weeks  and  at 8th  week cystourethroscopy performed along with detail  evaluation of symptoms of urethral stricture to know  recurrence of stricture.  RESULTS:   81.39% patients have no urethral stricture on cystourethroscopy  and symptomatic evaluation at 8th week  post visual internal urethrotomy  while 18.60%  patients have recurrent urethral stricture . Length of urethral stricture is the most important prognostic factor, stricture of less than 1 cm has success rate of 62.39% while stricture of more than one cm length has success rate of 20% as shown in table IV.  CONCLUSION:  In this study it has been confirmed that CISC  is safe ,cost effective procedure and most of the patients can do it in home with out any complications.

    Idiopathic multicentric Castleman disease: a mysterious case of generalized lymphadenopathy

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    Castleman disease is a syndrome with significant clinico-pathological overlap between malignancy, autoimmune causes and infectious etiologies. It is a spectrum and can vary in extent from unicentric to multicentric disease with generalized lymphadenopathy, organ involvement, constitutional symptoms and cytopenias, and in severity from non-severe to severe disease with TAFRO symptoms. Idiopathic multicentric Castleman disease (iMCD) is a diagnosis of exclusion after multiple causes as per diagnostic criteria are excluded. Treatment varies between the disease severity types with anti-IL 6 antibodies for non-severe disease to cytotoxic chemotherapy agents for severe disease with TAFRO symptoms. We hereby report a case of a non-severe type of iMCD with a prolonged course and delayed arrival at the diagnosis, owing to the rarity of this condition, which stresses the need for a reduced threshold to consider MCD, early in the differential diagnosis. Interestingly there were positive auto-antibodies and elevated IgG4 levels in this patient, but applying strict criteria helps to distinguish the diagnosis
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