1,430 research outputs found

    Enhanced toluene removal using granular activated carbon and a yeast strain candida tropicalis in bubble-column bioreactors

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    The yeast strain Candida tropicalis was used for the biodegradation of gaseous toluene. Toluene was effectively treated by a liquid culture of C. tropicalis in abubble-column bioreactor, and the tolueneremoval efficiency increased with decreasing gas flow rate. However, toluene mass transfer from the gas-to-liquid phase was a major limitation for the uptake of toluene by C. tropicalis. The tolueneremoval efficiency was enhanced when granularactivatedcarbon (GAC) was added as a fluidized material. The GAC fluidized bioreactor demonstrated tolueneremoval efficiencies ranging from 50 to 82% when the inlet toluene loading was varied between 13.1 and 26.9 g/m3/h. The yield value of C. tropicalis ranged from 0.11 to 0.21 g-biomass/g-toluene, which was substantially lower than yield values for bacteria reported in the literature. The maximum elimination capacity determined in the GAC fluidized bioreactor was 172 g/m3/h at atoluene loading of 291 g/m3/h. Transient loading experiments revealed that approximately 50% of the toluene introduced was initially adsorbed onto the GAC during an increased loading period, and then slowly desorbed and became available to the yeast culture. Hence, the fluidized GAC mediated in improving the gas-to-liquid mass transfer of toluene, resulting in a high tolueneremoval capacity. Consequently, the GAC bubble-column bioreactor using the culture of C. tropicalis can be successfully applied for the removal of gaseous toluene

    Higher Dimensional Inhomogeneous Perfect Fluid Collapse in \emph{f(R)} Gravity

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    This paper is about the n+2n+2-dimensional gravitational contraction of inhomogeneous fluid without heat flux in the framework of f(R)f(R) metric theory of gravity. Matching conditions for two regions of a star has been derived by using the Darmois junction conditions. For the analytic solution of equations of motion in modified f(R)f(R) theory of gravity, we have taken scalar curvature as constant. Hence final result of gravitational collapse in this frame work is the existence of black hole and cosmological horizons, both of these form earlier than singularity. It has been shown that constant curvature term f(R0)f(R_{0}) (R0R_0 is constant scalar curvature) slows down the collapsing process.Comment: 17 Pages, to appear in European Physical Journal

    Pengembangan Media Pembelajaran Berbasis Software Macromedia Flash 8 dan Power Point pada Materi Pokok Asam Basa

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    Penelitian ini merupakan penelitian pengembangan media pembelajaran yang dilakukan di Pesantren/Madrasah Aliyah Madani Pao-Pao Gowa. Penelitian ini bertujuan untuk: (i) mengetahui proses pengembangan media pembelajaran; (ii) mengetahui kualitas media pembelajaran yang meliputi kevalidan, keefektifan, dan kepraktisan. Langkah-langkah yang dilakukan yaitu; (i) Menuliskan tujuan pembelajaran umum berupa SK/KD; (ii) Melakukan analisis instruksional; (iii) Mengidentifikasi tingkah laku awal/karakteristik siswa kelas XI IPA; (iv) Merumuskan tujuan instruksional khusus; (v) Menyusun tes acuan patokan; (vi) Menyusun strategi pembelajaran; (vii) Mengembangkan media pembelajaran dengan menggunakan aplikasi macromedia flash dan power point; (viii) Merancang dan melaksanakan evaluasi formatif berupa validasi media; (ix) Melakukan revisi; (x) Melakukan ujicoba. Hasil penelitian menunjukkan bahwa (i) Proses pengembangan media pembelajaran meliputi beberapa tahap, yaitu: tahap identifikasi, tahap pengembangan media, dan tahap uji coba dan evaluasi; (ii) Kriteria perangkat pembelajaran yang dicapai yaitu: (1) valid berdasarkan penilaian validator, (2) praktis berdasarkan kemampuan guru mengelola pembelajaran berada dalam kategori tinggi dan respon siswa, dan (3) efektif berdasarkan ketuntasan klasikal telah tercapai dimana sebesar 85% siswa mengalami ketuntasan dan aktivitas siswa dan guru sudah terlaksana

    Generalized second law of thermodynamic in modified teleparallel theory

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    This study is conducted to examine the validity of the generalized second law of thermodynamics (GSLT) in flat FRW for modified teleparallel gravity involving coupling between a scalar field with the torsion scalar T and the boundary term B=2āˆ‡Ī¼TĪ¼B=2āˆ‡Ī¼TĪ¼ . This theory is very useful, since it can reproduce other important well-known scalar field theories in suitable limits. The validity of the first and second law of thermodynamics at the apparent horizon is discussed for any coupling. As examples, we have also explored the validity of those thermodynamics laws in some new cosmological solutions under the theory. Additionally, we have also considered the logarithmic entropy corrected relation and discuss the GSLT at the apparent horizon

    Situating Islamic feminism(s): Lived religion, negotiation of identity and assertion of third space by Muslim women in Pakistan

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    Ā© 2017 This paper reports the findings of an exploratory, qualitative study with Pakistani women to explore how Muslim women studying English in higher education contexts in Pakistan engage with feminist thought. The broader aim of the study was to capture the relationship between these women's ā€˜secularā€™ education and their religious (and secular) social identities as young, urban, middle class working women in a Pakistani higher education context. In particular, the study sets out to explore how Pakistani women at higher education institutions interact with and use ā€˜newā€™ forms of knowledges, particularly those dominated by western frameworks of intellectual thought and reasoning, in the context of their own potentially different social lives and self-identities as Muslim women. The findings show that the young women academics in addition to negotiating with the Western notions of Feminism also simultaneously challenge the indigenous patriarchal hegemonies and conservative religious discourses in their social context by attempting to rework notions of Muslim women's identity in Pakistan, envisaging what Bhabha has termed a third space

    Thermodynamics in f(R,RĪ±Ī²RĪ±Ī²,Ļ•) theory of gravity

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    First and second laws of black hole thermodynamics are examined at the apparent horizon of FRW spacetime in f(R,RĪ±Ī²RĪ±Ī²,Ļ•) gravity, where R, RĪ±Ī²RĪ±Ī² and Ļ• are the Ricci invariant, Ricci tensor and the scalar field respectively. In this modified theory, Friedmann equations are formulated for any spatial curvature. These equations can be presented into the form of first law of thermodynamics for ThdSĖ†h+ThdiSĖ†h+WdV=dE, where diSĖ†h is an extra entropy term because of the non-equilibrium presentation of the equations and ThdSĖ†h+WdV=dE for the equilibrium presentation. The generalized second law of thermodynamics (GSLT) is expressed in an inclusive form where these results can be represented in GR, f(R) and f(R,Ļ•) gravities. Finally to check the validity of GSLT, we take some particular models and produce constraints of the parameters

    Static spherically symmetric wormholes in generalized f(R, Ļ•) gravity

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    In this paper, we examine static spherically symmetric wormhole solutions in generalized f(R,Ļ•) gravity. To do this, we consider three different kinds of fluids: anisotropic, barotropic and isotropic. We explore different f(R,Ļ•) models and inspect the energy conditions for all of those three fluids. It is found that under some models in this theory, it is possible to obtain wormhole solutions without requiring exotic matter. The discussion about the conditions where the standard energy conditions (WEC and NEC) are valid for the fluids is discussed in details. From our results and for our cases, we conclude that for anisotropic and isotropic fluids, realistic wormhole geometries satisfying the energy conditions can be constructed

    Scalable parallel communications

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    Coarse-grain parallelism in networking (that is, the use of multiple protocol processors running replicated software sending over several physical channels) can be used to provide gigabit communications for a single application. Since parallel network performance is highly dependent on real issues such as hardware properties (e.g., memory speeds and cache hit rates), operating system overhead (e.g., interrupt handling), and protocol performance (e.g., effect of timeouts), we have performed detailed simulations studies of both a bus-based multiprocessor workstation node (based on the Sun Galaxy MP multiprocessor) and a distributed-memory parallel computer node (based on the Touchstone DELTA) to evaluate the behavior of coarse-grain parallelism. Our results indicate: (1) coarse-grain parallelism can deliver multiple 100 Mbps with currently available hardware platforms and existing networking protocols (such as Transmission Control Protocol/Internet Protocol (TCP/IP) and parallel Fiber Distributed Data Interface (FDDI) rings); (2) scale-up is near linear in n, the number of protocol processors, and channels (for small n and up to a few hundred Mbps); and (3) since these results are based on existing hardware without specialized devices (except perhaps for some simple modifications of the FDDI boards), this is a low cost solution to providing multiple 100 Mbps on current machines. In addition, from both the performance analysis and the properties of these architectures, we conclude: (1) multiple processors providing identical services and the use of space division multiplexing for the physical channels can provide better reliability than monolithic approaches (it also provides graceful degradation and low-cost load balancing); (2) coarse-grain parallelism supports running several transport protocols in parallel to provide different types of service (for example, one TCP handles small messages for many users, other TCP's running in parallel provide high bandwidth service to a single application); and (3) coarse grain parallelism will be able to incorporate many future improvements from related work (e.g., reduced data movement, fast TCP, fine-grain parallelism) also with near linear speed-ups
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