Closed Form Solution of Plane-Parallel Turbulent Flow Along an Unbounded Plane Surface

In this paper, a century-old problem is solved; namely, to find a unified analytic description of the non-uniform distribution of mean velocity across the entire domain of turbulent flow for all Reynolds numbers within the framework of the Prandtl mixing length theory. This study obtains a closed form solution of the mean velocity profile of plane turbulent flow for the Prandtl theory, and as well an approximate analytical solution for the van Driest mixing length theory. The profiles of several useful quantities are given based the closed form solution, such as turbulent viscosity, Reynolds turbulent stress, Kolmogorov's scaling law, and energy dissipation density. The investigation shows that the energy dissipation density at the surface is finite, whereas Landau's energy dissipation density is infinite. Strictly speaking, the closed form solution reveals that the universality of the turbulent velocity logarithmic profile no longer holds, but the von K\'arm\'an constant is still universal. Furthermore, a new formulation of the resistance coefficient of turbulent flow in pipes is formulated in implicit form.

‘Same storm – Different boats’: A Southern African Methodist response to socio-economic inequalities exposed by the COVID-19 storm

This article critiques the theological basis for the Methodist Church of Southern Africa’s response to the socio-economic impact of the coronavirus disease 2019 (COVID-19) pandemic. In light of the fact that there are few (if any) clergy historical accounts on how to respond to a deadly pandemic like COVID-19, this article is an analytic description that weaves together narrative renditions of the authors’ experiences with formal correspondence of the institution’s documentation on the inequalities exposed by the imposition of the lockdown in South Africa and countries that form part of the Methodist Connexion. Theological questions of human dignity, solidarity, and economic justice that have been surfaced by the pandemic are also raised. The article makes practical observations and offers insights that contribute to the ongoing dialogue and institutional strategies for responding to COVID-19. It further offers a resource for future researchers and communities who may respond to a similar pandemic in the future.

Closed Form Solution of Plane-Parallel Turbulent Flow Along an Unbounded Plane Surface

In this letter, a century-old problem is studied; namely, to find a unified analytic description of the non-uniform distribution of mean velocity across the entire domain of turbulent flow for all Reynolds numbers within the framework of the Prandtl mixing length theory. Considering the Prandtl mixing length model, a closed form solution of the mean velocity profile of plane turbulent flow is obtained, and approximate analytical solution of the van Driest mixing length theory is proposed. The profiles of several useful quantities are given, such as turbulent viscosity, Reynolds turbulent stress, Kolmogorov's scaling law, and energy dissipation density. It is shown that the energy dissipation density at the surface is finite, whereas Landau's energy dissipation density is infinite. The closed form solution reveals that the universality of the turbulent velocity logarithmic profile no longer holds, but the von K\'arm\'an constant is still universal. Furthermore, a new formulation of the resistance coefficient of turbulent flow in pipes is given in implicit form.

Surface Laplacian of interfacial thermochemical potential: its role in solid-liquid pattern formation

Steady-state solid-liquid interfaces allow both analytic description as sharp-interface profiles, and numerical simulation via phase-field modeling as stationary diffuse-interface microstructures. Profiles for sharp interfaces reveal their exact shapes and allow identification of the thermodynamic origin of all interfacial capillary fields, including distributions of curvature, thermochemical potential, gradients, fluxes, and surface Laplacians. By contrast, simulated diffuse interface images allow thermodynamic evolution and measurement of interfacial temperatures and fluxes. Quantitative results using both approaches verify these capillary fields and their divergent heat flow, to provide insights into interface energy balances, dynamic pattern formation, and novel methods for microstructure control. The microgravity environment of low-Earth orbit was proven useful in past studies of solidification phenomena. We suggest that NASA’s ISS National Lab can uniquely accommodate aspects of experimental research needed to explore these novel topics.

Closed Form Solution of Plane-Parallel Turbulent Flow Along an Unbounded Plane Surface

In this letter, a century-old problem is studied; namely, to find a unified analytic description of the non-uniform distribution of mean velocity across the entire domain of turbulent flow for all Reynolds numbers within the framework of the Prandtl mixing length theory. Considering the Prandtl mixing length model, a closed form solution of the mean velocity profile of plane turbulent flow is obtained. The profiles of several useful quantities are given, such as turbulent viscosity, Reynolds turbulent stress, Kolmogorov's scaling law, and energy dissipation density. It is shown that the energy dissipation density at the surface is finite, whereas Landau's energy dissipation density is infinite. The closed form solution reveals that the universality of the turbulent velocity logarithmic profile no longer holds, but the von K\'arm\'an constant is still universal. The closed form solution is validated by both direct numerical simulation and experiments. The studies confirm that the van Driest mixing length theory is suitable for smooth walls, and the Prandtl mixing length theory is suitable for rough walls. Furthermore, a new formulation of the resistance coefficient of turbulent flow in pipes is given in implicit form.

Faktor-Faktor yang berhubungan dengan Pencapaian Kepuasan Layanan Masa Nifas

One of the measuring tools for midwifery services is said to be of quality if a midwifery service can satisfy the client according to the level of satisfaction. Client satisfaction is influenced by internal factors and external factors. Internal factors come from the client himself (age, education, pregnancy distance, parity, and occupation) and external factors such as actions given by health workers. Client satisfaction is not only the responsibility of top management but has become the culture and commitment of all employees. The lower the quality of health services, the lower the level of patient satisfaction. The purpose of the study was to determine the factors associated with the achievement of postpartum service satisfaction. This type of research is an analytic description with a cross-sectional design. The sample of this study was postpartum mothers who received services from pregnancy to childbirth by midwives at Independent Practice Midwives (PMB) in Agam and Pasaman Regencies. The sampling technique was using accidental sampling with a period of 1 month, namely from July 1 to July 31, 2020, as many as 69 postpartum mothers. The data is processed by computer. Analysis of the data using the Chi-Square test. The results showed that the factors associated with postpartum service satisfaction were age, education level and service quality. Meanwhile, for parity and work factors, there is no relationship with postpartum service satisfaction. This study concludes that the variables associated with postpartum service satisfaction are age, education level and service quality, while parity and workers have no relationship with the respondent's level of satisfaction with the services they provide.

An analytic description of the creep deformation of metals in the ultrasonic field

The effect of superimposed ultrasonic vibration on the primary creep of metals is modeled in terms of the synthetic theory of irrecoverable deformation. We consider two sonication modes: (i) the ultrasound acts continuously during the deformation, and (ii) the ultrasound is periodically on and off. Whereas both cases show a significant increase in primary creep, the periodical sonication leads to higher deformation values. To catch the phenomenon of ultrasound-assisted creep, we extend the flow rule equation by a term that accounts for the process occurring on the microlevel of material induced by ultrasound.

Conservation Strategy for Palm Groves: Optimal Chemical Control Model for Red Palm Weevil, Rhynchophorus ferrugineus

Rhynchophorus ferrugineus (Olivier, 1790) is an invasive pest species that constitutes one of the most important problems around the Mediterranean region and has been responsible for the loss of over 100,000 palm trees with an estimated annual cost of EUR several hundred million since its introduction into Europe. Methodological approaches of conservation ecology, such as multidisciplinary modelling, also apply in the management of cultural landscapes concerning ornamental plants, such as palm trees of the area. In this paper, we propose a dynamic model for the control of the red palm weevil, contributing in this way to the sustainability of an existing cultural landscape. The primary data set collected is a sample from the density-time function of a two-cohort pest population. This data set suggests a bimodal analytic description. If, from this data set, we calculate a sample from the accumulated density-time function (the integral of the density-time function), it displays a double sigmoid function (with two inflections). A good candidate for the analytical description of the latter is the sum of two logistic functions. As for the dynamic description of the process, a two-dimensional system of differential equations can be obtained, where the solution’s second component provides the analytical description of the original density-time function for the two-cohort population. Since the two-cohort waves appear in all three cycle stages, this reasoning applies to the subpopulations of larvae, pupae and adults. The model fitting is always performed using the SimFit package. On this basis, a mathematical model is proposed, which is sufficiently versatile to be of help in the control of this pest species in other geographical areas.

The intricacies of counting to four in Old English poetry

The metrical theory devised by Eduard Sievers and refined by A. J. Bliss forms the basis for most current scholarship on Old English meter. A weakness of the Sievers–Bliss theory is that it occupies a middle ground between two levels of analytic description, distinguished by Roman Jakobson in an influential article as ‘verse instance’ and ‘verse design’. Metrists in the Sievers–Bliss tradition employ a concept of metrical position (a key component of verse design), yet the focus of attention usually remains on the contours of stress of individual verses. Important exceptions are the studies of Thomas Cable and Nicolay Yakovlev. The theoretical innovations of Cable and Yakovlev, among others, enable a more concise presentation of verse design than anyone writing on the subject has yet offered. The present essay attempts to show what such a presentation might look like, while also giving due acknowledgment to the complexities of position-count in this meter. We presume no prior knowledge of the Sieversian system. Illustrations are drawn principally from Cædmon’s Hymn and the Seafarer.