Reducibility of Eulerian Graphs and Digraphs

In this paper the concept of reducibility in graph theory is discussed, and the deletable vertex (edge) in graph (digraph) is defined. The class of graphs (digraphs) ℛ is called vertex (edge) reducible if for any G∈ ℛ either ℛ is the trivial graph (null graph) or it contains a vertex (edge) v such that G-v∈ ℛ. We introduce some classes of graphs (digraphs) which are reducible and others which are not. The vertex reducibility and edge reducibility of Eulerian graphs and Eulerian digraphs have also been studied

Effect of dissolved oxygen and chemical oxygen demand to nitrogen ratios on the partial nitrification/denitrification process in moving bed biofilm reactors

Partial nitrification was reported to be technically feasible and economically favorable, especially for wastewater with high ammonium concentration or low C/N ratio. In this study, the effect of dissolved oxygen (DO) and influent ratio of chemical oxygen demand to nitrogen (COD/N) ratio on biological nitrogen removal from synthetic wastewater was investigated. Experiments were conducted in moving bed biofilm reactors (MBBRs) on partial nitrification process in pilot-plant configuration for 300 days. DO levels were changed from 0.04 to 0.12 and 0.42 to 3.4 mg/l in the anoxic (R1) and aerobic (R2) reactors, respectively. The optimum DO for partial nitrification was between 1-1.5 mg/l in the aerobic reactor (R2). Influent COD/N ratios between 20 and 2 g COD/g-N were tested by changing the nitrogen loading rate (NLR) supplied to the pilot plant. During operational conditions when the DO concentration in aerobic reactor was above 1 mg/l, near complete organic carbon removal occurred in the total MBBRs system. The effluent total nitrogen concentration in the operational conditions (1.7-2.1 mg O2/l and NH+ 4-N=35.7 mg N/l) was obtained in the range of 0.85-2 mg/l. The highest nitrite accumulation (50%- 52%) took place at the DO concentration of 1-1.5 mg/l and increased with decreasing COD/N ratio in aerobic reactor (R2). This study showed that the average nitrification rate at various COD/N ratios is about 0.96 gN/m2 per day while the maximum nitrification rate is about 2 gN/m2 per day at COD/N ratios lower than 6. The experimental COD/N ratio for denitrification was close to complete sum of NO2 - and NO3 - (NOx) removal efficiency (about 99%) at COD/N ratio equal 14 in the operational conditions in the anoxic reactor (R1)

Effectiveness of chitosan as natural coagulant aid in removal of turbidity and bacteria from turbid waters

There has been considerable interest in the development of natural coagulants such as chitosan. By using natural coagulants, considerable savings in chemicals and sludge handling cost may be achieved. Chitosan, a natural linear biopolyaminosaccharide, is obtained by alkaline deacetylation of chitin. Present study is aimed to examine the effects of aluminium sulfate (alum) as coagulant in conjunction with chitosan as coagulant aid on removal of turbidity and bacteria from turbid waters. These tests were carried out using artificial water and kaoline as model suspensions to represent the wide range of natural turbid waters. A conventional jar test apparatus was employed for the tests. After determining of optimum mixing intensity and duration, alum suspensions were added to the samples and after one minute, the desired doses of natural chitosan were added. In optimum condition, residual Al+3 in treated water was less than 0.2 mg/l and meets the EPA guidelines. Turbidity removal efficiency was 74.3- 98.2% by chitosan at a pH 7.0-7.5 for all turbidities. In addition, chitosan significantly reduced the required dosage of primary coagulant 50-87.5%. Bacteria reduction of 2-4 log units (99 - 99.99%) was obtained within the first 1 to 2 h of treatment. Overall results indicate that E.coli was removed better than S. faecalis. The main effects of coagulation by chitosan on bacteria are enmeshment and stack on the microbial cell surface. We demonstrated that optimal design method is an efficient approach for optimization of coagulation-flocculation process and appropriate for raw water treatment

Analisis Potensi dan Arahan Strategi Kebijakan Pengembangan Desa Ekowisata di Kecamatan Bumiaji Kota Batu

Kota Batu merupakan salah satu daerah otonom di Provinsi Jawa Timur yang mengandalkan sektor pariwisata untuk meningkatkan pendapatan asli daerah (PAD). Pengembangan pariwisata lebih mengarah pada objek wisata artifisial atau buatan yang dibangun oleh investor namun menimbulkan permasalahan lingkungan. Perlu alternatif lain pengembangan pariwisata yaitu obyek wisata yang mampu menekan dampak kerusakan lingkungan sekaligus meningkatkan peran masyarakat lokal dan kesejahteraannya yaitu pengembangan Desa Ekowisata berbasis Community Based Ecotourism (CBE). Penelitian ini bertujuan untuk melakukan penilaian potensi wisata dan obyek daya tarik wisata (ODTW) di desa desa wisata, menganalisis kesiapan terhadap pengembangan desa ekowisata, menganalisis desa wisata yang paling optimal untuk pengembangan desa ekowisata dan menentukan arahan strategi kebijakan pengembangan desa ekowisata di Kecamatan Bumiaji Kota Batu. Penelitian ini merupakan penelitian deskriptif. Pengumpulan data dengan survei primer dan sekunder. Pendekatan yang digunakan adalah Analisis potensi wisata dan obyek daya tarik wisata (ODTW), Penilaian kesiapan pengembangan Community Based Ecotourism (CBE), Analisis spasial dan Analisis SWOT. Hasil penelitian menunjukkan seluruh desa wisata di Kecamatan Bumiaji memiliki potensi wisata dan obyek daya tarik wisata (ODTW) berupa atraksi alam, sumberdaya pertanian dan budaya yang dapat lebih dikembangkan. Penilaian potensi wisata dan obyek daya tarik wisata (ODTW) menunjukkan Desa Tulungrejo dan Desa Sumberbrantas termasuk klasifikasi Sangat Baik; Analisis kesiapan terhadap pengembangan desa ekowisata berbasis masyarakat (CBE) menunjukkan Desa Tulungrejo dan Desa Bumiaji termasuk dalam klasifikasi Baik. Hasil analisis spasial menunjukkan Desa Tulungrejo merupakan desa yang paling optimal untuk pengembangan desa ekowisata di Kecamatan Bumiaji. Analisis Matrik Grand Strategy menunjukkan arahan strategi kebijakan pengembangan Desa Ekowisata di Desa Tulungrejo terletak pada kuadran 1, strategi yang digunakan bersifat agresif (SO). Kata Kunci : Kota Batu, pengembangan, potensi dan ODTW, Desa Ekowisat

Analisis Potensi dan Arahan Strategi Kebijakan Pengembangan Desa Ekowisata di Kecamatan Bumiaji Kota Batu

Kota Batu merupakan salah satu daerah otonom di Provinsi Jawa Timur yang mengandalkan sektor pariwisata untuk meningkatkan pendapatan asli daerah (PAD). Pengembangan pariwisata lebih mengarah pada objek wisata artifisial atau buatan yang dibangun oleh investor namun menimbulkan permasalahan lingkungan. Perlu alternatif lain pengembangan pariwisata yaitu obyek wisata yang mampu menekan dampak kerusakan lingkungan sekaligus meningkatkan peran masyarakat lokal dan kesejahteraannya yaitu pengembangan Desa Ekowisata berbasis Community Based Ecotourism (CBE). Penelitian ini bertujuan untuk melakukan penilaian potensi wisata dan obyek daya tarik wisata (ODTW) di desa desa wisata, menganalisis kesiapan terhadap pengembangan desa ekowisata, menganalisis desa wisata yang paling optimal untuk pengembangan desa ekowisata dan menentukan arahan strategi kebijakan pengembangan desa ekowisata di Kecamatan Bumiaji Kota Batu. Penelitian ini merupakan penelitian deskriptif. Pengumpulan data dengan survei primer dan sekunder. Pendekatan yang digunakan adalah Analisis potensi wisata dan obyek daya tarik wisata (ODTW), Penilaian kesiapan pengembangan Community Based Ecotourism (CBE), Analisis spasial dan Analisis SWOT. Hasil penelitian menunjukkan seluruh desa wisata di Kecamatan Bumiaji memiliki potensi wisata dan obyek daya tarik wisata (ODTW) berupa atraksi alam, sumberdaya pertanian dan budaya yang dapat lebih dikembangkan. Penilaian potensi wisata dan obyek daya tarik wisata (ODTW) menunjukkan Desa Tulungrejo dan Desa Sumberbrantas termasuk klasifikasi Sangat Baik; Analisis kesiapan terhadap pengembangan desa ekowisata berbasis masyarakat (CBE) menunjukkan Desa Tulungrejo dan Desa Bumiaji termasuk dalam klasifikasi Baik. Hasil analisis spasial menunjukkan Desa Tulungrejo merupakan desa yang paling optimal untuk pengembangan desa ekowisata di Kecamatan Bumiaji. Analisis Matrik Grand Strategy menunjukkan arahan strategi kebijakan pengembangan Desa Ekowisata di Desa Tulungrejo terletak pada kuadran 1, strategi yang digunakan bersifat agresif (SO). Kata Kunci : Kota Batu, pengembangan, potensi dan ODTW, Desa Ekowisat

Pilot-scale studies of combined clarification, filtration, and ultraviolet radiation systems for disinfection of secondary municipal wastewater effluent

Disinfection of municipal wastewater effluent was evaluated using three alternatives, including: (1) low-pressure (LP)+medium-pressure (MP) UV lamps; (2) clarifier+LP+MP; and (3) pressurized sand filter+ LP+MP. Total coliform (TC), fecal coliform (FC), fecal Streptococcus (FS), TSS, several physicochemical parameters, absorbtivity and UV transmittance (UVT; ) were tested. The UVT for secondary, clarified and filtered effluents were 3.5, 34 and 50, respectively. A 15 photo-reactivation in secondary effluent disinfected by LP lamp was observed, while it was limited to 0.03 by the MP lamp after filtration. Filtration to a surface overflow rate (SOR) of 1050 L/m2h, followed by MP irradiation at a dose of 230 mW s/cm2 was an effective alternative to reduce the TC, FC, and FS in the disinfected secondary effluent. Filtration+MP lamp met the standards of 1000 TC and 400 FC/100 mL for effluent discharge to receiving waters. This process can also inactivate FS, effecting a 6-log reduction. Among the evaluated alternatives, none of the other treatment systems performed as well as the pressurized sand filter+MP lamp, making this the best combination for post-treatment and disinfection of secondary effluent from a well-run wastewater treatment plant. © 2010 Elsevier B.V. All rights reserved

Towards More Effective Techniques for Automatic Query Expansion

Techniques for automatic query expansion from top retrieved documents have recently shown promise for improving retrieval effectiveness on large collections but there is still a lack of systematic evaluation and comparative studies. In this paper we focus on term-scoring methods based on the differences between the distribution of terms in (pseudo-)relevant documents and the distribution of terms in all documents, seen as a complement or an alternative to more conventional techniques. We show that when such distributional methods are used to select expansion terms within Rocchio's classical reweighting scheme, the overall performance is not likely to improve. However, we also show that when the same distributional methods are used to both select and weight expansion terms the retrieval effectiveness may considerably improve. We then argue, based on their variation in performance on individual queries, that the set of ranked terms suggested by individual distributional methods can be combined to further improve mean performance, by analogy with ensembling classifiers, and present experimental evidence supporting this view. Taken together, our experiments show that with automatic query expansion it is possible to achieve performance gains as high as 21.34% over non-expanded query (for non-interpolated average precision). We also discuss the effect that the main parameters involved in automatic query expansion, such as query difficulty, number of selected documents, and number of selected terms, have on retrieval effectiveness