Electrokinetic Control of Viscous Fingering

We present a theory of the interfacial stability of two immiscible electrolytes under the coupled action of pressure gradients and electric fields in a Hele-Shaw cell or porous medium. Mathematically, our theory describes a phenomenon of "Vector Laplacian Growth", in which the interface moves in response to the gradient of a vector-valued potential function through a generalized mobility tensor. Physically, we extend classical Saffman-Taylor problem to electrolytes by incorporating electrokinetic phenomena. A surprising prediction is that viscous fingering can be controlled by varying the injection ratio of electric current to flow rate. Beyond a critical injection ratio, stability depends only upon the relative direction of flow and current, regardless of the viscosity ratio. Possible applications include porous materials processing, electrically enhanced oil recovery, and electrokinetic remediation of contaminated soils.Comment: * Fixed a few typos * Added new discussion of possible liquid pairs * Added new reference

Memory and mutualism in species sustainability: a time-fractional Lotka-Volterra model with harvesting

We first present a predator-prey model for two species and then extend the model to three species where the two predator species engage in mutualistic predation. Constant effort harvesting and the impact of by-catch issue are also incorporated. Necessary sufficient conditions for the existence and stability of positive equilibrium points are examined. It is shown that harvesting is sustainable, and the memory concept of the fractional derivative damps out oscillations in the population numbers so that the system as a whole settles on an equilibrium quicker than it would with integer time derivatives. Finally, some possible physical explanations are given for the obtained results. It is shown that the stability requires the memory concept in the model

Analisis Laba Kotor Penjualan Cat Pada Toko Timur Jaya Di Muara Jawa

Penjualan merupakan salah satu faktor dominan yang berperan penting dalam USAha untuk mempertahankan dan meningkatkan USAha yang sedang dijalankan. Setiap pengusaha yang menjual barang atau jasanya harus jeli untuk menganalisis hambatan serta peluang penjualan dalam persaingan pasar.Yang menjadi permasalahan dalam penelitian ini adalah manakah diantara Cat tembok Avitex, Komilex dan Cat tembok Aries yang memberikan sumbangan laba Kotor terbesar untuk penjualan cat pada Toko Timur di Muara Jawa.Dasar teori Manajemen Pemasaran yang menguraikan pengertian Manajemen Pemasaran dan membahas Analisa biaya pemasaran yang dilanjutkan dengan pembahasan manajemen penjualan dan konsep penjualan yang dirangkaikan dengan pembahasan Akuntansi Keuangan meliputi Harga Pokok Penjualan, Pengertian Laba, Analisis Laba Kotor dan Laporan Laba Rugi.Hipotesis dalam penelitian ini diduga bahwa penjualan Cat tembok Avitex memberikan sumbangan laba kotor yang lebih besar dibandingkan dengan penjualan Cat tembok Komilex dan Cat tembok Aries pada Toko Timur Jaya di Muara Jawa.Berdasarkan hasil analisis dan pembahasan diperoleh Jenis/merk Avitex yang menghasilkan laba Kotor terbesar dari ketiga jenis/ merk cat tembok yang dijual yaitu sebesar Rp. 7.007.000,- dengan Harga Pokok sebesar Rp. 96.733.000,- kemudian Cat tembok Komilex dengan laba kotor sebesar Rp 3.555.000,- dengan Harga Pokok Penjualan sebesar Rp. 55.365.000,- dan jenis/merk Aries dengan laba Kotor sebesar Rp. 1.551.000,- dengan Harga Pokok Penjualan sebesar Rp. 45.676.000.Besarnya laba kotor, dan Harga Pokok Penjualan pada Cat tembok Avitex yang tinggi dikarenakan : lebih banyak memiliki pilihan warna – warni cemerlang yang lagi trend pada saat ini, walaupun memiliki harga penjualan lebih tinggi, dari kedua jenis/merk cat yang dijual pada Toko Timur Jaya di Muara Jawa. Hipotesis pertama yang diajukan dalam penelitian ini adalah bahwa penjualan Cat Avitex, Komilex dan Aries memberikan sumbangan laba kotor pada Toko Timur Jaya diterima. Hipotesis kedua bahwa cat Avitex memberikan sumbangan Laba Kotor yang lebih besar dibanding cat Komilex dan cat Aries, terbukti dan dapat diterima

Trader Behaviour and Performance in Live Animal Marketing in Rural Ethiopian Markets

In this paper, performance of a sample of 131 livestock traders in 38 rural Ethiopian highland markets was analysed in terms of their costs and margins, how these were influenced by their assets and trading practices, and the implications of the findings for policy were outlined. The paper is divided into three main sections: description of the profiles of traders, their assets, trading behaviour and practices; estimates of costs and margins for a set of recent transactions; and econometric analysis of the factors explaining differences in performance with a particular focus on transaction costs. Most traders used own capital as access to credit, especially formal credit, was limited. The livestock market was characterised by non-standardised products and lack of information in the public domain about supply, demand and prices. Consequently, livestock trading was largely a personalised business though brokers and regular buyers and sellers, a form of social capital, were sometimes used for gathering information, searching buyers/sellers, price negotiation, contract enforcement. Business relationships with these intermediaries were principally based on trust, without strong ethnic, religious or family ties. Although most transactions were conducted in physical presence of parties, contract violations were common, which were settled mainly through informal means as formal legal systems were either absent or time consuming. Estimated costs and margins of case transactions showed low returns, and losses in some cases. Market levies, transport, travel, and feeds were major items of variable cost, with some variation between cattle and shoats. Multiple regression analysis showed that traders' financial and human capital and trading practices like use of brokers and regular suppliers and customers had varying effects on margins and costs of cattle and shoat trade. Unstable price, multiple taxes, non-transparent tax system, limited access to credit and weak demand for the quality of the products traded were perceived by traders as major problems of marketing. All the problems were amenable to public policy for improving the market environment and marketing efficiency.Livestock Production/Industries, Marketing, D4, L1, O1, Q13,

Immunohistochemical expression of p21 in normal tissues of salivary gland, pleomorphic adenoma and carcinoma ex pleomorphic adenoma (undifferentiated and adenocarcinoma types)

Objective: Our study aimed to characterize alteration in the immunohistochemical expression of p21 in normal tissue of the salivary gland surrounding pleomorphic adenoma, the tumor cells of pleomorphic adenomas, and carcinoma arising in pleomorphic adenoma. Study design: A selected series of 29 cases of pleomorphic adenomas, and 27 cases of carcinoma ex-pleomorphic adenoma (undifferentiated and adenocarcinoma types) were examined. Results: The results showed that p21 expression was negative in the most components of normal tissue of the salivary gland surrounding pleomorphic adenoma, 24 cases out of 29 of the non tumour duct cells (82.8%), and 28 (96.6%) cases out of 29 of the acinar cells shows negative p21 expression. P21 expression in pleomorphic adenomas shows that 2 cases out of 29 (6.9%) strongly expressed in the duct cells. p21 was strongly expressed in carcinoma cells in 9 (33.3%) cases out of 27. Conclusion: Our data suggest that the strong nuclear staining as an indicator for altered p21, then the alteration of p21 expression would increase from pleomorphic adenoma to carcinoma arising in pleomorphic adenomas (6.9% versus 33.3%)

HEER: Hybrid Energy Efficient Reactive Protocol for Wireless Sensor Networks

Wireless Sensor Networks (WSNs) consist of numerous sensors which send sensed data to base station. Energy conservation is an important issue for sensor nodes as they have limited power.Many routing protocols have been proposed earlier for energy efficiency of both homogeneous and heterogeneous environments. We can prolong our stability and network lifetime by reducing our energy consumption. In this research paper, we propose a protocol designed for the characteristics of a reactive homogeneous WSNs, HEER (Hybrid Energy Efficient Reactive) protocol. In HEER, Cluster Head(CH) selection is based on the ratio of residual energy of node and average energy of network. Moreover, to conserve more energy, we introduce Hard Threshold (HT) and Soft Threshold (ST). Finally, simulations show that our protocol has not only prolonged the network lifetime but also significantly increased stability period.Comment: 2nd IEEE Saudi International Electronics, Communications and Photonics Conference (SIECPC 13), 2013, Riyadh, Saudi Arabi