Analytical Modelling of Laminar Developing Flow Between Hydrophobic Surfaces with Different Slip-Velocities

Theoretical analysis of the entrance hydrodynamics of microchannels is an important design aspect in connection with the development of microfluidic devices. In this paper, pressure-driven fluid flow in the entrance region of two infinite hydrophobic parallel plates with dissimilar slip-velocities is analytically modelled. The linearized momentum equation is solved by applying the Navier-slip model at the boundaries to achieve the most generalized two-dimensional form. The velocity profile is obtained by combining the developed and developing velocities, which is estimated by invoking the separation of variable method. It is observed that the velocity profile is asymmetric and the shear-free region can be shifted from the geometrical central line by altering the wall hydrophobicity. Moreover, the zero shear zone is transferred more towards the surface having high hydrophobicity. The expression for wall shear stress is obtained analytically using Newton's law of viscosity. Moreover, the boundary layer growth from the upper and lower walls are found to be entirely different and they merge at the entrance length and is noticed to be off-setted from the geometric centre-line. The effect of slip-length on the entrance length is analysed and an empirical correlation is deduced.

ALTERNATIF VARIABLE COSTING SEBAGAI PENENTUAN HARGA PRODUK PADA IWAI CAKE & BAKERY

During the current pandemic and the movement of society, forcing entrepreneurs to carry out various activities to survive in these difficult times. Various actions such as providing attractive promotions, discounted prices, efficiency in the production process, even innovating and calculating product cost estimates. The variable costing method is an alternative to determine the price of the product that is used to increase the accuracy of the selling price of the product. In general, entrepreneurs use an easier method by adding all the costs incurred in calculating the cost of the product, which we know as the full costing method. The purpose of the counseling is the preparation and application of the variable costing method in calculating the selling price. In order to improve the accuracy, it is necessary to sort costs based on their nature, namely the separation of variable costs and fixed costs. In an effort to help MSME actors to survive, I as a lecturer from Tarumanaga University, Faculty of Economics and Accounting proposed the owner of Iwai Cake & Bakery to help calculate the cost of products through preparation, implementation in business units with the title "Variable Costing as an alternative costing to improve price accuracy productPada masa pandemi saat ini dan pembatasan pergerakan dari masyarakat, memaksa para pengusaha melakukan berbagai aktifitas untuk tetap dapat bertahan dimasa yang sulit ini. Berbagai Tindakan seperti memberikan promo-promo yang menarik, potongan harga, efisiensi dalam proses produksi bahkan melakukan inovasi dan kalkulasi perhitungan penentuan harga pokok produk. Metode variable costing merupakan salah satu alternatif penentuan harga produk yang dipakai untuk meningkatkan keakuratan penentuan harga jual produk. Secara umum para pengusaha menggunakan metode yang lebih mudah dengan menambahkan semua biaya yang dikeluarkan dalam perhitungan harga pokok produk yang kita kenal dengan metode full costing. Tujuan dari penyuluhan adalah penyusunan dan penerapan metode variable costing dalam menghitung harga produknya. Untuk meningkatkan keakuratan harus dilakukan pemilahan biaya berdasarkan sifatnya yaitu pemilahan biaya yang bersifat variable dan biaya-biaya yang bersifat tetap. Dalam upaya membantu pelaku UMKM supaya tetap bertahan, Saya selaku dosen dari Universitas Tarumanaga Fakultas Ekonomi Jurusan Akuntansi mengajukan ke pemilik Iwai Cake & Bakery dengan membantu melakukan perhitungan harga pokok produk melalui penyusunan, implementasi di unit usaha dengan judul “Variable Costing sebagai alternatif costing untuk meningkatkan keakuratan penentuan harga produk

An Extended Separation-of-Variable Method for Free Vibration of Rectangular Mindlin Plates

For rectangular thick plates with non-Levy boundary conditions, it is important to explore analytical free vibration solutions because the classical inverse and semi-inverse exact solution methods are not applicable to this category of problems. This work is to develop an extended separation-of-variable (SOV) method to find closed-form analytical solutions for the free vibration of rectangular Mindlin plates with arbitrary homogeneous boundary conditions. In the extended SOV method, characteristic differential equations and boundary conditions in two directions are obtained by employing the Rayleigh principle and the assumption that the mode functions are in the SOV form, and two transcendental eigenvalue equations are achieved through boundary conditions. But these two eigenvalue equations cannot be solved simultaneously since there are two equations and only the natural frequency is the unknown variable. Considering this, the second assumption in this method is that the natural frequencies corresponding to two-direction mode functions are independent of each other in the mathematical sense, thus there are two unknowns in two transcendental eigenvalue equations, and the closed-form solutions for plates with arbitrary boundary conditions can be obtained non-iteratively. From the physical sense, the natural frequencies pertaining to different direction mode functions should be the same, and this conclusion is validated analytically and numerically. The present natural frequencies and mode shapes agree well with those obtained by other analytical and numerical methods. Especially, for the plates with at least two opposite sides simply supported, the present solutions are exact.

ANALYTICAL APPROACH TO THE PENNE’S BIOHEAT EQUATION FOR THE EVALUATION OF TEMPERATURE FOR DEEP SEATED TISSUES

In clinical practice, body temperature is an acclaimed indicator for diagnosis and treatments amongst other follow - ups. This work studied the temperature distribution in deep-seated tissues using Penne’s bio-heat equation (PBE). The analytical solution of the PBE was formulated using the separation of variable technique. The resulting solution gives an expression for tissue temperature in organs that are located inside the body. This revealed that the tissue temperature is subject to changes in tissue thickness, the distance of tissue from the skin surface and other thermal properties of tissues under consideration.

Duby: Dual Binding Semantics

Reference counting is a simple and efficient method for garbage collection. One disadvantage of reference counting is the possible creation of reference cycles. We propose a dynamically typed compiled programming language called Duby, in which values can be bound to either an automatic variable or to a unique hierarchical path. The separation of variable binding forms allows Duby to implement reference counting for automatic variables which refer to values bound to unique hierarchical paths without creating reference cycles. Another advantage of explicit binding of values to unique hierarchical paths is the ability to provide a paradigmatic implementation of programming concepts using filesystem-like abstractions.