bluuebunny/crossref_metadata_2025_split huggingface dataset:
KOMBINASI ULTRAFILTRASI DAN DISSOLVED AIR FLOTATION UNTUK PEMEKATAN MIKROALGA
Authors: Widiasa I Nyoman , Susanto A A , Budiyono B 
Published: May 2015

Abstrak Mikroalga merupakan mikroorganisme fotosintetik prokariotik atau eukariotik yang dapat tumbuh dengan cepat. Pemanfaatan mikroalga tidak hanya berorientasi sebagai pakan alami untuk akuakultur, tetapi terus berkembang untuk bahan baku produksi pakan ternak, pigmen warna, bahan farmasi (β-carotene, antibiotik, asam lemak omega-3), bahan kosmetik, pupuk organik, dan biofuel (biodiesel, bioetanol, biogas, dan biohidrogen. Studi ini bertujuan untuk menginvestigasi kombinasi ultrafiltrasi (UF) – dissolved air flotation (DAF) untuk pemekatan mikroalga skala laboratorium. Hasil penelitian menunjukkan bahwa penurunan fluks membran UF secara tajam sebagai akibat dari deposisi sel mikroalga terjadi pada 20 menit pertama proses filtrasi. Backwash pada interval 20 menit selama 10 detik dengan tekanan 1 bar memberikan pengendalian fouling yang efektif dalam nilai kestabilan fluks yang layak. Membran UF yang digunakan dapat memberikan selektivitas pemisahan biomassa mikroalga ~ 100%. Kualitas permeat sangat stabil, yaitu kekeruhan < 0,5 NTU, kandungan organik < 10 mg/L, dan warna < 10 PCU. Lebih lanjut, pemekatan retentat membran dengan DAF pada tekanan saturasi 6 bar dapat menghasilkan pasta mikroalga dengan konsentrasi 20 g/L. Koagulan PAC perlu ditambahkan kedalam umpan DAF dengan dosis 1,3–1,6 mg PAC/mg padatan tersuspensi. Kata Kunci: ultrafiltrasi; dissolved air flotation; pemanenan mikroalga; pemekatan mikroalga Abstract COMBINATION OF Ultrafiltration and Dissolved Air Flotation for Microalgae CONCENTRATION. Microalgae is a prokaryotic photosynthetic microorganism or eukaryotic microorganism that proliferate rapidly. Cultivation of the microalgae is not only oriented as natural food for aquacultures, but also developed for animal food, color pigment, pharmaceutical raw material (β-carotene, antibiotic, fatty acid omega-3), cosmetic raw material, organic fertilizer, and biofuels (biodiesel, bioethanol, biogas, and biohydrogen. This study is aimed to investigate the potential of combination of ultrafiltration (UF) and dissolved air flotation (DAF) for concentration of microalgae in laboratory scale. The experimental results showed that fluxes of the UF membrane decreased sharply due to deposition of microalgae biomass during first 20 minutes of filtration. Periodically backwash using the UF permeate (backwash interval = 20 minutes; backwash duration = 10 seconds; backwash pressure = 1 bar) gave an effective fouling control to maintain reasonable stable fluxes. In addition, the UF membrane gave separation of microalgae biomass ~ 100%. Permeate quality is strongly stable in which turbidity < 0.5 NTU, organic content < 10 mg/L, and color < 10 PCU. Moreover, concentration of the UF retentate by DAF under saturation pressure of 6 bars was able to produced microalgae feedstock having 20 g/L dry microalgae. PAC is required for DAF feed with dosage of 1.3–1.6 mg PAC/mg suspended solids.
Histomorphological study of the gut developmental pattern in early life history stages of featherback, Chitala chitala (Hamilton)
Authors: Mitra Anisa , Mukhopadhyay Pratap Kumar , Homechaudhuri Sumit 
Published: May 2015

Abstract
The present study was conducted to observe morphological and histological changes in the developing digestive system during the ontogeny of featherback, Chitala chitala (Hamilton), from hatching to 30 days post hatch (dph). Three significant stages were identified during digestive tract development in featherback: (1) endotrophic (0-8 dph), (2) endoexotrophic (8-12 dph), and (3) exotrophic (12-30 dph). At hatching, the mouth was closed and the digestive tract was a straight tube. At 8 dph, the mouth was opened and the appearance of the esophagus was observed. Between 6-8 dph, the primordial liver and exocrine pancreas were observed. Intestinal enterocyte activity was observed before stomach development. The esophageal goblet cells, teeth, and taste buds developed 2 days after the opening of the mouth, at the time of exogenous feeding. The development of the stomach, gastric glands, and pyloric caeca took place between the 7 and 12 dph. Except the increase in size and complexity of the structures, no noticeable changes were observed after 12 dphin C. chitala during the experiment. Our findings in the current work provide valuable information which might be useful for improving current larval rearing techniques of this promising new candidate species for freshwater aquaculture diversification.
Changes in macrophyte communities in Lake Swarzędzkie after the first year of restoration
Authors: Rosińska Joanna , Gołdyn Ryszard 
Published: May 2015

Abstract
Lake Swarzędzkie, near Poznań, was a hypertrophic lake because of its high nutrient content, cyanobacteria blooms, and disruptive recreational use, especially swimming, which was popular there. This is why protection measures have been in place since 1991, and a restoration program has been ongoing since fall 2011. The evaluation of the presence and distribution of macrophytes as an important element of lake ecosystem was conducted in August 2012. Nine plant communities were observed: Phragmitetum communis; Typhetum angustifoliae; Nupharo-Nymphaeetum albae; Hydrocharitetum morsus-ranae; Thelypteridi-Phragmitetum; Cicuto-Caricetum pseudocyperi; Acoretum calami; Ceratophylletum demersi; Potametum lucentis. The first three were dominating associations. The presence of submerged vegetation appears to verify the positive impact of the applied conservation and restoration measures. Improvement is confirmed by the significant decrease in concentrations of chlorophyll-a and total nitrogen, as well as the gradual decrease in total suspended solids and increased transparency.
Intraspecific morphological variation between cultured and wild Clarias gariepinus (Burchell) (Clariidae, Siluriformes)
Authors: Solomon Shola G. , Okomoda Victor T. , Ogbenyikwu Abel I. 
Published: May 2015

Abstract
This study was designed to evaluate morphological differences between cultured and wild African catfish, Clarias gariepinus (Burchell). Fish samples were collected from the lower Benue River (axis in Makurdi), while cultured fish were obtained from the University of Agriculture Makurdi research farm. The results revealed significant sex-related variation in the fish from different environments. Significant differences were observed in all morphometric parameters measured and in three of the five meristic counts recorded. Discriminant analysis and cluster analysis of morphometric parameters showed a high divergence among the populations, hence the tested fish samples were grouped into respective environments by sex. The meristic count, however, overlapped broadly showing no divergence among the populations. The morphometric differences between the cultured and wild African catfish could have been linked to genetic differences or environmental factors or a combination of both factors.
Evaluating the potential of chitosan/poly(vinyl alcohol) membranes as alternative carrier material for proliferation of Vero cells
Authors: Sharma Parul , Mathur Garima , Goswami Navendu , Sharma Sanjeev K. , Dhakate Sanjay R. , Chand Subhash , Mathur Ashwani 
Published: May 2015

AbstractChitosan/poly(vinyl alcohol) (CS/PVA) blend membranes were prepared using the casting method and their physiochemical properties were analyzed using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). FTIR and XRD demonstrated possible hydrogen bonds between CS and PVA. The addition of PVA to CS resulted in surface roughness as analyzed by SEM. The CS/PVA blend membrane exhibited high tensile properties (81.62%) and reduced water-holding capacity (53.8%) compared to a pure CS membrane (control). Cell viability and proliferation were assessed via an MTT assay with Vero cell culture. Associated with improved physicochemical properties, the CS/PVA blend membrane promotes cell proliferation of Vero cells with high specific growth rate (0.582 day-1). The results demonstrate that the blending of CS and PVA could significantly alter the surface rugosity, water-holding capacity and improve the mechanical and biological properties of the membrane. Interestingly, this concept can be extended for different anchorage-dependent cell lines, as an alternative carrier material.
Solidarisch finanzierte und bezahlbare Versorgung im Krankheitsfall – wie lässt sie sich sichern?
Authors: Rawert Mechthild , Hinteregger Sigrid 
Published: May 2015

Einleitung
Die Finanzierung unseres Gesundheitssystems steht regelmäßig im Zentrum der gesundheitspolitischen Debatte – zu Recht. Die Gestaltung der Finanzierung wirkt weit reichend: auf die Bezahlbarkeit des Gesundheitssystems, auf die Verteilung der Beitragslast, die bessere Erfüllung des Solidarprinzips, die Versorgungsqualität und Zugangschancen zur gesundheitlichen Versorgung. Für diese Gestaltungsfelder bietet die Bürgerversicherung umfassende Lösungen und Chancen.
Unsaturated flow characteristics in dual-scale fibre fabrics at one-dimensional constant flow rate
Authors: Shilin Yan , Fei Yan , Dequan Li , Yongjing Li 
Published: May 2015

Abstract
Fibre fabrics in liquid composite moulding can be considered as dual-scale porous media. In different gap scales, an unsaturated flow is produced during the mould filling process. This particular flow behaviour deviates from the traditional Darcy’s law, which is used to calculate the filling pressure and will cause errors. To prove the mechanism of this unsaturated flow, an experimental device was set up with a one-dimensional constant flow rate. The influencing factors, such as injected media, flow velocity and fibre fabric, were investigated in this study. Based on the experimental data, several useful conclusions were drawn, providing good references for optimising the process parameters and controlling the product quality.
The interaction of delignification and fiber characteristics on the mechanical properties of old corrugated container fiber/polypropylene composite
Authors: Niaraki Pouria Rezaee , Latibari Ahmad Jahan , Rashno Arash , Tajdini Ajang 
Published: May 2015

AbstractThe effect of fiber characteristics from old corrugated container (OCC) paper on the strength properties of OCC/polypropylene composites was evaluated. Fibers with different contents of lignin (2.8%, 3.8%, 5.3%, and 7%) were produced using soda pulping. Wettability, tear, and tensile strength of the fibers were measured as the indication factors to assess the strength of reinforcing component in the composites. The weight portions of the OCC fibers, polypropylene, and maleic anhydride-grafted polypropylene (MAPP) were selected at 20%, 77%, and 3% of the total weight of the composite, respectively. The composite compounds were formed using a counter-rotating twin screw extruder, and the specimens were made in an injection molding machine. The interaction of fiber characteristics and fiber lignin content on the mechanical properties of composite was investigated. The results revealed that with lower fiber lignin content, both flexural and tensile properties were increased. Consequently, by forming better fiber dispersion and by reducing stress regions in the composite, impact strength was also improved. Lower lignin content resulted in better mechanical properties than fiber characteristics.
Colloidal PbS Nanosheets with Tunable Energy Gaps
Authors: Jiang Zhoufeng , Khan Simeen , Premathilake Shashini , Bhandari Ghadendra , Subedi Kamal , He Yufan , Leopold Matthew , Reilly Nick , Lu Peter , Zayak Alexey , Sun Liangfeng 
Published: May 2015

ABSTRACTUltrathin colloidal PbS nanosheets are synthesized using organometallic precursors with chloroalkane cosolvents, resulting in tunable thicknesses ranging from 1.2 nm to 4.6 nm. We report the first thickness-dependent photoluminescence spectra from lead-salt nanosheets. The one-dimensional confinement energy of these quasi-two-dimensional nanosheets is found to be proportional to 1/L instead of 1/L2 (L is the thickness of the nanosheet), which is consistent with results calculated using density functional theory as well as tight-binding theory.
Role of Stoichiometry on Ordering in Ni-Cr Alloys
Authors: Teng Fei , Tucker Julie D. 
Published: May 2015

ABSTRACTMechanical property degradation due to an ordering phase transformation is a concern for alloys based on the Ni-Cr binary system (e.g., 690, 625), particularly in nuclear power applications, such as stream generator tubing, reactor pressure vessel and head control rod drive mechanism penetrations, where component lifetimes can exceed 40 years. In the present research, the disorder-order phase transformation has been studied in Ni-Cr model alloys with varying stoichiometry by experimental methods. In this paper, the effect of composition on ordering is characterized via X-ray diffraction.
THE RWANDAN GENOCIDE IN FILM, AND A SUNDAY IN KIGALI: WATCHING WITH A PIERCED EYE
Authors: Defraeye Piet 
Published: May 2015

Susan Sontag reminds us that film and photography have an extremely democratic heuristic poetics, and are quasi-universally accessible for signification, though at the same time, it almost always implies a prime target audience. The many films that have come out on the Rwandan genocide (1994) are no exception. Film has been a prime access source to this bloody event and dominates, particularly in the West, our remembrance and understanding of one of the most intense and grueling political conflicts in African history. All these films struggle with a compulsive need for structured narration, whether it is in their fable, or in the visual representation itself, while the historical events were certainly not experienced as part of a linear structure. At the same time, the films aim for historical credibility, or truthfulness, which is rendered through a variety of filmic approaches. The article discusses the fictionalization of genocide through film, and problematizes the quasi-unavoidable documentary effect of filmic iteration. Robert Favreau’s Un Dimanche à Kigali is analyzed in greater detail, as it offers specific strategies to the problem of filmic representation of genocidal violence.
Programar é bom para as crianças? Uma visão crítica sobre o ensino de programação nas escolas
Authors: Geraldes Wendell Bento 
Published: May 2015

RESUMO: O artigo apresenta reflexões sobre o ensino de programação nas escolas e os impactos positivo e negativo dessa prática nos dias atuais. O texto trata ainda das iniciativas relativas ao ensino de programação nas escolas, considerando também a opinião de alguns especialistas sobre o assunto. Afinal, é bom para as crianças aprender a programar computadores nas escolas? Todas as pessoas podem aprender a programar computadores? Qual a importância da aprendizagem de programação para a sociedade atual? Em busca das respostas a essas questões, serão discutidas aqui as vantagens e desvantagens a respeito deste tema.PALAVRAS-CHAVE: educação; escolas; software; computador; inovação. ABSTRACT: This article presents reflections on teaching programming in schools and the positive and negative impact of this new methodology today. The study also discusses the initiatives relating to teaching programming in schools, considering also the opinion of experts on the subject. The following questions are addressed: Is it good for children to learn to program computers in schools? Can all people learn to program computers? What is the importance of learning for today's society? The pros and cons regarding teaching programming in schools will be discussed in search of answers to these questions.KEYWORDS: education; schools; software; computer; innovation.
Profitabilities on Federal Offshore Oil and Gas Leases: A Review
Authors: Lohrenz J. 
Published: May 2015

ABSTRACT
Studies which assess profitabilities from Federal offshore oil and gas leases consistently point to unsatisfactory performance. That is true for leases issued years ago as well as for the future even with presently optimistic oil and gas price projections. Bonus paid is the controllable factor that delivers the coup de grace to acceptable profits. Elimination of bonus may not make profitabilities robust, but could make them closer to the average for all industries. This review leads to a simple prescription. For profitabilities closer to a satisfactory level, hid less bonus.
A Generalized Compositional Model for Naturally Fractured Reservoirs
Authors: Peng C. P. , Yanosik J. L. , Stephenson R. E. 
Published: May 2015

ABSTRACT
This paper presents the formulation of a generalized dual porosity compositional reservoir model. This formulation uses component masses and pressures as primary unknowns. The IMPES method with semi-implicit treatment of wells and the Newton-Raphson iteration method are used to solve the flow equations. The model has several different options for calculating fluid properties ranging in complexity from black oil to the Redlich-Kwong Equation of State (RKEOS). By proper ordering of equations, the model formulation is independent of the fluid property correlation used. It can simulate compositional problems rigorously and can simulate black oil problems as efficiently as a black oil dual porosity model.
The model can be used to study one-dimensional, two-dimensional and three-dimensional systems consisting of a combination of fractured and nonfractured rock using either cartesian or cylindrical coordinate systems. Either the five-point or nine-point finite difference schemes can be used in the areal plane. The effects of pressure depletion on rock compressibilities and permeabilities also can be simulated.
Using the RKEOS fluid property option, the model was used to study the depletion performance of dual porosity volatile oil and gas condensate reservoirs. The performance curves for volatile oil and gas condensate wells in a single porosity and a dual porosity system were generated and compared. The effects of capillary forces, gravity forces and matrix block size on the depletion performance were investigated. It was found that while the existence of fractures can be detrimental to the depletion performance of volatile oil reservoirs, its effects on the liquid recovery performance from gas condensate reservoirs are less pronounced.
Restored Productivity Using Dynamic Underbalance
Authors: Gasmi Khaled , Alarcon Bianca , Guerrero Monica , Daoud Mohamed 
Published: May 2015

Abstract
Perforations-reduced connectivity to the producing formation is an ongoing industry challenge. Whether it is caused by high debris or formation compaction, this reduction can be as high as 90%. Several methods were developed to overcome the reduction. Methods such as dynamic underbalance and acidizing bypass damage by using propellants or employing new process such as hydraulic fracturing.
Dynamic underbalance is an effective method to stimulate productivity when it is accurately applied using the right conditions at the initial perforation event. Some wells, however, face reduced productivity because of plugging in the existing perforations.
The case presented in this study examines the application of dynamic underbalance in a well that was treated by generating a surge at the level of the perforations, without resorting to elaborate and costly operations of re-perforating the zone, acidizing or using propellants. The technique was applied in a single wireline run which led to restored connectivity and yielded quadruple the rate of productivity.
This paper emphasizes the need for pre-job modelling to avoid unnecessary operations, presents the associated sensitivity analysis, the deployment methodology and the sequence of operations, as well as the operational advantages over other cleanup methods. Additionally, it assesses the conditions that make a well a good candidate for dynamic underbalance while reducing complex logistics and mitigating the risks of failure. Finally, it presents the results of the operation and increased productivity.
Development and Field Application of an Innovative, Minimally Damaging, Low-ECD Invert Emulsion Fluid for Enhanced Drilling and Completion of HP/HT Wells
Authors: McMillan D. Nelson , Lunde Odd Halvard , Mikalsen Renate , Mæland Yngve , Wroblewski Tomasz , Vatne Åsgeir , Dillner Birgitte 
Published: May 2015

Abstract
This paper describes the first field application of a high-pressure/high-temperature (HP/HT) organophilic clay-free invert emulsion fluid (OCF IEF) weighted with small-particle-sized (SPS) barite, qualification of which was achieved through extensive laboratory investigations (described elsewhere). The paper describes detailed observations of the fluid performance during first use (i.e., “critical first well application”) on a Statoil-operated HP/HT field in the North Sea.
In the well selected for first application, finger-printing was performed so that behaviors of the 1.96-specfic gravity (sg) invert emulsion fluid (IEF) could be examined and recorded before entering the open hole. When in the open hole, observational tests were continued throughout the well. Before and after trips, fluid behavior and properties were monitored and recorded. Additionally, extensive fluid testing was conducted on the rig (rheology, HP/HT fluid loss, particle plugging test [PPT] static sag, and viscometer sag shoe test [VSST]). Before running stand-alone screens (SAS), screen flow-through tests were performed.
Extensive tests showed acceptable fluid performance within stringent, defined criteria at all times. When re-initiating circulation on several consecutive connections, pump ramp-up time was gradually reduced. No pressures above drilling equivalent circulating density (ECD) were observed at any time. While drilling, the ECD values were maintained well within the required values. No barite sag was observed on any occasion, even after 90 hours static or during a slow circulation rate test performed to simulate conditions likely to induce dynamic sag. Fluid loss control (PPT) was maintained within specifications through the addition of ground marble. A decrease of approximately 60% in fluid treatments compared to a conventional HP/HT IEF resulted in a reduction in chemical and logistical costs and manual handling. The well was drilled well ahead of plan, resulting in saved rig time. No issues were observed when running screens to total depth (TD) with the IEF. The well was easily brought on production after ∼30 days, with the IEF being produced back to surface, consistent with expectations from the qualification laboratory testing undertaken at Statoil's laboratory facilities. Highly acceptable production rates were achieved, indicating minimal productivity impairment.
The efficient drilling of the well, along with being able to complete the well in the same IEF and not displace to brine, as was previously performed, resulted in substantial cost savings compared to other qualified solutions. This successful first application demonstrated that the well could be drilled and completed in the same fluid with an enhanced drilling performance and highly acceptable productivity outcome.