bluuebunny/crossref_metadata_2025 huggingface dataset:
Avaliação do risco de incêndio em centros urbanos antigos parte I – aplicação do método de ARICA ao centro histórico do Funchal
Authors: Figueira Rui , Rodrigues João Paulo C. , Leça Coelho António
Published: March 2015

A diferente concepção e materiais usados nas construções antigas fazem com que estas apresentem um risco de incêndio agravado. Tendo como objectivo avaliar o risco de incêndio do centro histórico do Funchal aplicaram-se os métodos de Gretener e ARICA a alguns edifícios característicos. A aplicação dos métodos permitiu não só verificar o risco de incêndio como detectar as diferenças entre os métodos.
Cultura de risco e segurança coletiva no Brasil: a vulnerabilidade socioespacial a jusante de Itaipu Binacional
Authors: Soriano Érico , Valencio Norma F. L S.
Published: March 2015

Vivemos numa sociedade que se baseia numa cultura de risco, ou seja, em que a condição do risco não é aceita e/ou divulgada para a maior parte da população. Para corresponder a essa cultura do risco, emergiu uma cultura de segurança para lidar com os novos riscos surgidos por conta do progresso acaba por reger a normalidade da vida social moderna. Uma produção social de risco no Brasil é a produção de barragens, principalmente os Grandes Projetos Hidrelétricos. Este trabalho terá como base os riscos associados à UHE Itaipu Binacional e a vulnerabilidade das populações a jusante.
In Defense of Mali’s Gold: The Political and Military Organization of the Northern Upper Niger, c. 1650–c. 1850
Authors: Jansen Jan
Published: March 2015

This analysis offers a compelling alternative to the received wisdom that the Mali Empire had dissolved by the end of the seventeenth century. It will be demonstrated that between 1650 and 1850, to the north of the gold fields of the Mali Empire the rulers of Kangaba successfully managed a defense zone. Using military and organizational innovations attributed to polities east of the Niger River (Kong, Segu [Ségou], Kano), they fused the political heritage of the Mali Empire with a system of triads of refuges or fortifications. Throughout the zone, groups of mercenaries of different ethnic origins were assimilated into the Kangaba polity and integrated into the political organization as well as Mali’s political ideology. The defense zone protected the gold fields from northern military pressure, in particular from the Bambara Segu kingdom, as well as from small bands of marauders and, later, the armies of El Hadji Umar. By elaborating a regional military-strategic focus that pays close attention to the landscape, and by using the concept of warrior state as a heuristic device, this article mobilizes a variety of hitherto unused archival, architectural, genealogical, and geographical sources. This article does a historiographic reassessment of the dominance of oral traditions as sources for the study of the history of the Mali Empire and the Upper Niger.
Finding the Historical Wangrin or the Banality of Virtue
Authors: Austen Ralph A.
Published: March 2015

The hero of Amadou Hampâté Bâ’s canonical book, L’étrange destin de Wangrin, was a historical figure. However, the rich, if incomplete, colonial records of this individual’s career as an interpreter and clerk in French West Africa indicate that he was far less corrupt or heroic than the person depicted in what we now have to call a novel. This work makes use of real historical incidents but misplaces and distorts them, indicating that Hampâté Bâ’s was inspired as much by literary tropes as by empirical reality. The banal virtue of the historical Wangrin (and even that of his shadier rival, the interpreter Romo Sidebi/Moro Sidibé) also suggests a break between the incentives and opportunities for corruption in the “classical” interwar colonial era and the late- and postcolonial conditions that have produced far more consequential patterns of African administrative malfeasance.
Reflections on Legitimation and Pedagogy in the “Islamic Revolutions” of West Africa on the Frontiers of the Islamic World
Authors: Robinson David
Published: March 2015

In an effort to create elements of comparability across reform movements at the frontiers of the Islamic world, this article examines issues of legitimation and pedagogy in the five widely reported movements of reform in the western and central Sudan in the eighteenth and nineteenth centuries. Among the three most intentional efforts to legitimate reform and jihad, the “Muhammadan” form followed carefully by Uthman dan Fodio in Hausaland was the most successful and easily generalized. I then turn to the issue of pedagogy and the development of vernacular literatures (‘ajami) for the spread of Islam. The most widely developed were those of Sokoto, on the one hand, and Futa Jalon and, especially, Labe, on the other. These literatures of recitation enabled reformers to expand practice beyond the merchant and urban elites to reach the non- or less-literate people (e.g., slaves, women, and those in the rural areas generally) through recitation of poetry and narrative about Islam. At the end, I suggest a possible alternative path to the creation of vernacular literature, in the marriage of griot skills to the use of Arabic.
The role of telomeres and vitamin D in cellular aging and age-related diseases
Authors: Pusceddu Irene , Farrell Christopher-John L. , Di Pierro Angela Maria , Jani Erika , Herrmann Wolfgang , Herrmann Markus
Published: March 2015

Aging is a complex biological process characterized by a progressive decline of organ functions leading to an increased risk of age-associated diseases and death. Decades of intensive research have identified a range of molecular and biochemical pathways contributing to aging. However, many aspects regarding the regulation and interplay of these pathways are insufficiently understood. Telomere dysfunction and genomic instability appear to be of critical importance for aging at a cellular level. For example, age-related diseases and premature aging syndromes are frequently associated with telomere shortening. Telomeres are repetitive nucleotide sequences that together with the associated sheltrin complex protect the ends of chromosomes and maintain genomic stability. Recent studies suggest that micronutrients, such as vitamin D, folate and vitamin B12, are involved in telomere biology and cellular aging. In particular, vitamin D is important for a range of vital cellular processes including cellular differentiation, proliferation and apoptosis. As a result of the multiple functions of vitamin D it has been speculated that vitamin D might play a role in telomere biology and genomic stability. Here we review existing knowledge about the link between telomere biology and cellular aging with a focus on the role of vitamin D. We searched the literature up to November 2014 for human studies, animal models and in vitro experiments that addressed this topic.
Salix viminaliswood as a new precursor for
manufacturing of carbon molecular sieves for
effective methane/nitrogen separation
Authors: Gorska Olga , Cyganiuk Aleksandra W. , Olejniczak Andrzej , Ilnicka Anna , Lukaszewicz Jerzy P.
Published: March 2015

Separation of a methane/nitrogen gas mixture
was investigated by means of carbon molecular sieves
(CMS) obtained from a newly discovered “green” resource:
Salix viminalis. This plant grows quickly, yields hard
wood and is frequently cultivated for energy purposes
(renewable green fuel). Unconventional applications
such as charcoal fabrication using this sort of wood are
very rare. Carbonization of the wood (1–3 h, 600–700°C)
yields carbons with a very narrow pore size distribution
(determined by N2 adsorption at -196°C) resembling
a perfect CMS. The diameter of most pores (ca. 0.8 nm) is
comparable to the size of simple molecules, thus enabling
separation. The sieving effect was proven in an industrially
important process of CH4/N2 separation at 30–70°C. Despite
relatively minor differences of the size of the molecules,
the experiment demonstrated that separation factors are
placed in the range 3.64–10.20. Additional experiments
involving krypton proved that the separation mechanism
is based on a geometric factor i.e. the known size and
shape of the molecules under separation.
Systematic Flexibility and the History of the IUPAC Nomenclature of Organic Chemistry
Authors: Hepler-Smith Evan
Published: March 2015

For chemists and chemistry students around the world, “IUPAC” is synonymous with “nomenclature” – especially the nomenclature of organic chemistry. Generations of chemists have learned – sometimes grudgingly – to read and write systematic names for organic compounds using guidelines codified by the International Union of Pure and Applied Chemistry. [1,2,3] The prefixes, suffixes, numbers, and parentheses of IUPAC names put molecules in order: individually, by expressing the network of atoms and bonds that constitutes the structure of an organic compound, and collectively, by situating each compound among the tens of millions of known organic chemical substances. IUPAC names carry this order out of chemical journals and into such sites as patent records, customs lists, and environmental regulatory databases.
Graphene Protein Field Effect Biomedical Sensor for Glucose Measurements
Authors: Liepmann Dorian , Aran Kiana , Ajayan Pulickel M. , Viswanathan Sowmya , Li Pingzuo , Renugopalakrishnan V.
Published: March 2015

The need for improved medical sensors based on lab-on-a-chip technologies has increased significantly because of the dramatic growth in the number of people with chronic diseases and the associated costs for their healthcare. Development and initial results of a hybrid plastic microfluidic device with an integrated graphene-protein biosensor chip for use in point-of-care (POC) is described. The initial prototype is a glucometer that uses optimized glucose oxidase bound to a graphene field effect sensor. Technologies required for development of the prototype include modification of the glucose oxidase for improved performance by protein engineering, methods to bind the enzyme to the graphene attached to the silicon oxide surface of sensor chip, and integration into a thermoplastic microfluidic device. Initial results indicate the prototype glucometer can measure glucose concentrations from low physiological levels to molar concentrations.
Routes to Control the Chemical Potential and to Modulate the Reactivity of Nanodiamond Surfaces
Authors: Reina Giacomo , Orlanducci Silvia , Gay Stefano , Gismondi Angelo , Lavecchia Teresa , Terranova Maria Letizia , Tamburri Emanuela
Published: March 2015

The use of detonation nanodiamond (DND) for drug delivery and cell-imaging is grounded on its chemical functionalization, and the key task to be addressed is the capability to simplify the process steps, to reduce the process times and to maximize the drug/ligand uptake. The idea underlying the present research is to modulate the loading capability of DND by controlled modification of the surface organic groups. To this aim the DND samples are treated either by wet chemistry, using medium-strong reducing agents, or by tunable H-plasmas produced in a custom-designed MW-RF reactor. The affinity of the treated DND surfaces for drugs has been probed by conjugating the ciproten (5,7- dimethoxycoumarin), a natural antioxidant molecule, and by testing in vitro the feasibility to use coumarin vehicled by nanodiamond (C@DND) as chemioterapeutic drug. The methodologies developed to modify the DND surfaces are offering practical solutions to the still open problems related to DND-based systems for drug delivery applications.
Technetium Getters to Improve Cast Stone Performance
Authors: Neeway James J. , Lawter Amanda R. , Serne R. Jeffrey , Asmussen R. Matthew , Qafoku Nikolla P.
Published: March 2015

A cementitious waste form known as Cast Stone is the baseline waste form for solidification of aqueous secondary wastes, including Hanford Tank Waste Treatment and Immobilization Plant (WTP) secondary liquid effluents to be treated and solidified at the Hanford Site Effluent Treatment Facility. Cast Stone is also being evaluated as a possible supplemental immobilization technology to provide the necessary low activity waste (LAW) treatment capacity to complete the Hanford tank waste cleanup mission in a timely and cost effective manner. Two radionuclides of particular concern in these waste streams are technetium-99 (99Tc) and iodine-129 (129I). These radioactive tank waste components are predicted to contribute the most risk to groundwater – the most probable pathway for future environmental impacts associated with the cleanup of the Hanford site. A recent environmental assessment of Cast Stone performance, which assumes a diffusion controlled release of contaminants from the waste form, calculates groundwater in excess of the allowable maximum permissible concentrations for both contaminants. There is, therefore, a need and an opportunity to improve the retention of both 99Tc and 129I in Cast Stone. One method to improve the performance of Cast Stone is through the addition of “getters” that selectively sequester Tc and I, therefore reducing their diffusion out of Cast Stone. In this paper, we present results of Tc and I removal from solution with various getters. Batch sorption experiments were conducted with deionized water (DIW) and a highly caustic LAW simulant with a 7.8 M average Na concentration. In general, the data show that the selected getters are effective in DIW but their performance is compromised when experiments are performed with the 7.8 M Na Ave LAW simulant. The diminished performance in the LAW simulant may be due to competition with Cr present in the 7.8 M Na Ave LAW simulant and to a pH effect that may create a negatively charged surface that can repel negatively charged species.
Characteristics of Cementitious Paste for use in Deep Borehole Disposal of Spent Fuel and High Level Wasteforms
Authors: Collier Nick C , Travis Karl P , Gibb Fergus G F , Milestone Neil B
Published: March 2015

Deep borehole disposal (or DBD) is now seen as a viable alternative to the (comparatively shallow) geologically repository concept for disposal of high level waste and spent nuclear fuel. Based on existing oil and geothermal well technologies, we report details of investigations into cementitious grouts as sealing/support matrices (SSMs) for waste disposal scenarios in the DBD process where temperatures at the waste package surface do not exceed ∼190ºC. Grouts based on Class G oil well cements, partially replaced with silica flour, are being developed, and the use of retarding admixtures is being investigated experimentally. Sodium gluconate appears to provide sufficient retardation and setting characteristics to be considered for this application and also provides an increase in grout fluidity. The quantity of sodium gluconate required in the grout to ensure fluidity for 4 hours at 90, 120 and 140°C is 0.05, 0.25 and 0.25 % by weight of cement respectively. A phosphonate admixture only appears to provide desirable retardation properties at 90°C. The presence of either retarder does not affect the composition of the hardened cement paste over 14 days curing and the phases formed are durable under conditions of high temperature and pressure.
DRENAGEM, COMUNIDADE E SAÚDE: A MÁ UTILIZAÇÃO DA LAGOA DOS POTIGUARES EM MORRO BRANCO – NATAL/RN
Authors: Souza Deickson Lennon Galvão de , Hora Neto José Avelino da , Lopes Jussiele da Rocha , Ferreira Lindomar Barbosa , Guimarães Magno Elias de Souza , Barbosa Zuleica Helaine Costa
Published: March 2015

O presente estudo visa investigar as condições sócio-ambientais provenientes da má utilização da Lagoa dos Potiguares, localizada na comunidade de Morro Branco, em Natal/RN. Sabe-se que a lagoa de captação de águas pluviais constitui um sistema de microdrenagem unitário, isto é, destina-se apenas ao escoamento superficial das águas. Entretanto, devido a falta de condições básicas de saneamento, a população deposita de forma clandestina os resíduos de utilização doméstica, gerando problemas de saúde pública. Nesse artigo, focalizou-se a análise e discussão das transformações do espaço urbano e de suas paisagens decorrentes da degradação do sistema urbano de drenagem e do crescente processo de urbanização PALAVRAS-CHAVE: Drenagem Urbana, Lagoa de Captação, Lagoa dos Potiguares, Espaço, Paisagem.
A INFLUÊNCIA DO CAMPO MAGNÉTICO NA GERMINAÇÃO DE VEGETAIS
Authors: Sales Fábio Henrique Silva , Santos Dayanna Gomes , Padilha Luana Lopes
Published: March 2015

Atualmente pesquisa-se e estuda-se bastante o fenômeno eletromagnético nas mais variadas áreas do conhecimento, desde os efeitos do campo magnético gerado por aparelhos celulares a pesquisas envolvendo campos magnéticos artificiais em vegetais e na Biofísica. Tudo isto porque o discurso do desenvolvimento auto-sustentável é o alvo do momento, utilizar os recursos do meio sejam eles vegetais ou animais, de forma consciente, de modo que as gerações futuras possam desfrutar dos mesmos assim como nós. Outro campo de importância é o das pesquisas agrícolas, em que as descobertas e o desenvolvimento de técnicas serão sempre bem-vindos, em virtude das constantes agressões sofridas pelo meio, sejam elas de natureza antrópica, como as queimadas e o desmatamento, ou natural, como as pragas que atacam as plantações. Diante disso, torna-se interessante, estudos a respeito dos fatores que influenciam ou “potencializem” a germinação de sementes e o crescimento de vegetais, objetivando a recuperação de áreas até então inutilizadas. Com tal finalidade desenvolveu-se este Projeto de Pesquisa, cultivando algumas amostras de alface em laboratório, esperando-se que o campo magnético gerado pelo solenóide, atuasse sobre os íons que compõem a seiva bruta, facilitando assim a sua subida e consequentemente a aceleração do crescimento do vegetal.
RESPOSTAS ECOFISIOLOGICAS POR ESPÉCIES ARBÓREAS ACUMULADORAS DE FÓSFORO NA AMAZÔNIA
Authors: Oliveira Patricia Chaves de , Carvalho Claudio Reis de
Published: March 2015

Espécies Vegetais potencialmente acumuladores de fósforo (P) como Neea macrophylla e Cecropia palmata representam componentes de interesse no enriquecimento de capoeiras e em sistemas agroflorestais haja vista seu potencial em produzir mulch de melhor qualidade do que a maioria das espécies comuns em florestas secundárias na região Nordeste do Estado do Pará. Dessa forma, a importância em se conhecer os perfis fotossintéticos dessas espécies sob condições de campo e portanto seu potencial em formar biomassa poderá contribuir no entendimento das interações biofísicas entre planta (folha) e atmosfera sob condições limitantes de fósforo (P). Os resultados demonstraram que Cecropia palmata apresentou os maiores fluxos de CO2 do que demais espécies assim como transpiração e condutância estomática mantendo suas folhas com temperaturas mais baixas sinalizando uma estratégia de adaptação a períodos mais secos. A eficiência potencial fotossintética no uso de fósforo foi maior em Casearia arborea, espécie não acumuladora de fósforo.
DIAGNÓSTICO SÓCIO-ECONÔMICO DOS AGRICULTORES E O IMPACTO DO PROGRAMA BOLSA FAMÍLIA NA COMUNIDADE SÃO FRANCISCO, MUNICÍPIO DE CONCEIÇÃO, PARAÍBA
Authors: Lacerda Maxwell Brian Soaresde , Oliveira Anselmo Rodrigues de , Campos Vinícius Batista , Menezes Júnior José Carlos de
Published: March 2015

Objetivou-se realizar um trabalho para avaliar o impacto do programa Bolsa Família do Governo Federal na comunidade de São Francisco, município de Conceição – PB. O diagnóstico foi obtido por meio de um questionário, elaborado através de uma entrevista semi-estruturada, no qual foram abordadas informações sobre o perfil social e econômico dos moradores da localidade. Para a coleta de dados, foram selecionadas 22 famílias dos mais diferentes pontos da comunidade. Verificou-se uma grande variação entre a renda das pessoas entrevistadas. O analfabetismo é uma característica também dessa comunidade, não se diferenciando das comunidades e assentamentos rurais. A maioria das famílias considera o programa Bolsa Família muito bom, porém afirmam que viviam melhor antes de receber o benefício.
AVALIAÇÃO DO POTENCIAL FITORREMEDIADOR DA MAMONA (Ricinus communis L) UTILIZANDO EFLUENTE SINTÉTICO CONTENDO CHUMBO.
Authors: Lima Anita , Melo Josette Lourdes De Sousa , Melo Henio Normando De Souza , Carvalho Fabíola Gomes de
Published: March 2015

Os estudos de novas formas para o tratamento de efluentes domésticos e industriais vêm aumentando gradativamente no Brasil, neste contexto destacam-se as correntes que defendem a atenuação natural e a biorremediação. Por essas razões, em anos recentes, passou-se a dar preferência a métodos in situ, os quais são mais econômicos e perturbam menos o ambiente. Uma técnica de remediação natural é a fitorremediação que, aplica-se à utilização de vegetação (árvores, arbustos, plantas rasteiras e aquáticas) e de sua microbiota com o fim de remover, degradar ou isolar substâncias tóxicas ao ambiente. O presente trabalho teve como objetivo testar o capacidade de fitorremediação da mamona (Ricinus Communis L.) na redução das concentrações de chumbo presente em efluente sintético, cujas características simulam aquelas encontradas em um dos principais efluentes da indústria de exploração do petróleo, a água de produção tratada. O delineamento experimental utilizado no estudo foi o de blocos inteiramente casualizado com a variação das concentrações de chumbo distribuídas em quatro tratamentos: 0 µg/L (T1), 250 µg/L (T2), 500 µg/L (T3), 1000 µg/L (T4). Na análise dos dados foi aplicado o teste estatístico ANOVA para a comparação das médias nos tratamentos. A avaliação realizada nas concentrações de chumbo no lixiviado indicou que ocorreram remoções máximas de 67,42%, 87,34% e 94,74% para os tratamentos T2, T3 e T4, respectivamente. A retenção do chumbo nos tecidos (sistema radicular, caule e folhas) da mamona indicou que a planta apresentou boa capacidade de bioacumular o chumbo. PALAVRAS-CHAVE: Fitorremediação, Chumbo, Mamona.
Perineale Hypospadie bei einem rotbunten Deutsche-Holstein-Kalb
Authors: Hussein H. A. , Wehrend A. , Mihsler L.
Published: March 2015

Die Hypospadie ist eine beim Menschen sowie bei verschiedenen Tierarten vorkommende angeborene Missbildung der Harnröhre. Es wurden verschiedene chirurgische Vorgehensweisen zur Therapie beschrieben, doch ist eine Operation nicht in jedem Fall zwingend notwendig. In diesem Bericht wird der Fall eines Bullenkalbes mit perinealer Hypospadie vorgestellt, bei dem keine invasive Therapie durchgeführt werden musste.
A Pro106to Ala Substitution is Associated with Resistance to Glyphosate in Annual Bluegrass (Poa annua)
Authors: Cross Robert B. , McCarty Lambert B. , Tharayil Nishanth , McElroy J. Scott , Chen Shu , McCullough Patrick E. , Powell Brian A. , Bridges William C.
Published: March 2015

Glyphosate is used in the transition zone to control annual bluegrass in fully dormant warm-season grasses. A suspected resistant (R) biotype of annual bluegrass was identified on a golf course in South Carolina after at least 10 consecutive years of glyphosate application. Greenhouse bioassays revealed the R biotype was 4.4-fold resistant to glyphosate compared with a standard susceptible (S) biotype. Further studies were conducted to investigate the mechanism conferring glyphosate resistance in the R biotype. Leaf discs of both biotypes accumulated shikimate in response to increasing glyphosate concentration, but the glyphosate concentration resulting in 50% EPSP synthase inhibition as a result of shikimate accumulation (I50) was 4.2-fold higher in the R biotype compared with the S biotype. At the whole plant level, similar levels of shikimate accumulation were observed between biotypes at 6 and 24 h after treatment (HAT) with glyphosate, but greater shikimate accumulation occurred in the S biotype at 72, 120, and 168 HAT. Shikimate levels decreased in the R biotype after 72 HAT. There were no differences in14C-glyphosate absorption between biotypes. However, more14C-glyphosate translocated out of the treated leaf in the R biotype and into root tissues over time compared with the S biotype. Partial sequencing of the EPSP synthase gene revealed a point mutation that resulted in an Ala substitution at Pro106. Although other mechanisms may contribute to glyphosate resistance, these results confirm a Pro106to Ala substitution is associated with resistance to glyphosate in the R annual bluegrass biotype.
Crowding Out Effects of Refinancing on New Purchase Mortgages
Authors: Sharpe Steve A. , Sherlund Shane M.
Published: March 2015

We present evidence that binding mortgage processing capacity constraints reduce mortgage originations to borrowers with low to modest credit scores. Mortgage processing capacity constraints typically bind when the demand for mortgage refinancing shifts outward, usually because of lower mortgage rates. As a result, high capacity utilization leads mortgage lenders to ration mortgage credit, completing mortgages that require less underwriting resources, and are thus less costly, to produce. This is hypothesized to have a particularly adverse impact on relatively higher credit‐risk borrowers’ ability to obtain mortgages. What is more, we show that, by lowering capacity utilization, a rise in interest rates can, under certain circumstances, induce an increase in mortgage originations to relatively higher risk borrowers. In particular, we find fairly large effects for purchasing borrowers with low to modest credit scores, in which we find that a decrease in capacity utilization of 4 applications per mortgage employee (similar to that observed from 2012 to 2013) could result in increased purchase mortgage originations, as the relaxed capacity constraint might have offset any negative effect on mortgage demand from higher interest rates.
Crecimiento y producción de fruta en cultivares de fresa (Fragaria sp.) afectados por encharcamiento
Authors: Casierra-Posada Fánor , Vargas Yuber A.
Published: March 2015

En general, el exceso de agua tiene un impacto negativo sobre el crecimiento y supervivencia de la mayoría de las plantas terrestres, en especial, cuando el encharcamiento ocurre durante la estación de crecimiento. En un experimento en materas, en invernadero en Tunja/Colombia, se determinó, la producción y distribución de materia seca, el peso específico de las hojas, la relación raíz / parte aérea, el total de fruta cosechada, el área foliar necrótica y normal, el índice de cosecha y el pH del suelo luego del encharcamiento, en tres cultivares de fresa: Chandler, Camarosa y Sweet Charlie. Las plantas se desarrollaron en suelo encharcado y sin encharcar (testigo). Como consecuencia del exceso de agua, el pH del suelo, el peso específico y el área necrótica de las hojas y la relación raíz / parte aérea, se incrementaron; mientras que la fruta cosechada, la producción total de materia seca y el área foliar total se redujeron. El encharcamiento también modificó la distribución de materia seca en los cultivares evaluados siendo el cultivar Chandler el más afectado por el encharcamiento en comparación con los demás cultivares. En general, las plantas de fresa mostraron un comportamiento muy pobre cuando fueron expuestas a condiciones de encharcamiento.
Consumer patchiness explained by volatile infochemicals in a freshwater ecosystem
Authors: Moelzner Jana , Fink Patrick
Published: March 2015

Many animal species show considerable spatial variation in abundance within their habitats. Since they live in patchy environments where food resources are often heterogeneously distributed, it would be adaptive for them to have efficient chemoreceptive mechanisms to locate food resources over distances. In the current study we investigated whether gastropod consumers perceive and pursue odorant signals in three choice experiments which were conducted under semi‐natural conditions. We tested the foraging behavior of freshwater snails to targets containing odorant stimuli and whether the recognition of food finding signals subsequently leads to the aggregation of grazers on the corresponding resource patch. We demonstrate that freshwater gastropods are able to recognize odor bouquets as foraging infochemicals and that grazing of conspecifics causes an aggregation of grazers under natural conditions. Further, they appear to be able to distinguish between high‐ and low‐quality food resources based on resource‐quality specific odor bouquets. Our results suggest that the perception of volatile cues is a process relevant on environmental scales and thus a possible mechanism to explain the frequently observed patchy distribution of grazers in ecosystems.
Fire created habitat partitioning and isolation between hybridizing warblers
Authors: King R. S. , Boysen J. R. , Brenneman J. M. , Cong R. M. , Hunter T. S.
Published: March 2015

Hybridization or the breakdown of reproductive barriers has perplexed conservationists for centuries. Hybridization between the golden‐winged warbler (Vermivora chrysoptera) and blue‐winged warbler (Vermivora cyanoptera) has received extensive study across North America for more than a century and indicates widespread, bi‐directional genetic introgression. We found evidence fire is creating habitat conditions leading to isolation between nesting golden‐winged warblers and blue‐winged warblers. This effect is likely the result of fire's ability to promote grass cover and suppress woody plants, leading to habitat use partitioning between golden‐winged warblers and blue‐winged warblers. In addition to minimizing contact between the species, fire is creating habitat conditions on mixed sites that greatly favors golden‐winged warblers over blue‐winged warblers. Fire provides a plausible explanation for the original split in these sister species and its near elimination from eastern North America provides at least a partial explanation for the golden‐winged warbler's extensive range‐wide decline. Fire also provides a potential conservation tool by isolating golden‐winged warbler and blue‐winged warbler nesting populations. If nesting populations can be isolated, relatively rapid phenotypic sorting can be achieved, which could lead to a clearer distinction between the taxa as well as species preservation.
Evaluation of Scale Inhibitors in Marcellus High-Iron Waters
Authors: Shen Dong , Shcolnik David , Perkins Randall , Taylor Grahame , Brown Mike
Published: March 2015

The Marcellus waters of Pennsylvania and West Virginia commonly contain elevated levels of calcium, barium, and iron. Theoretical analyses of these waters indicate a propensity toward the formation of calcium carbonate, barium sulfate, strontium sulfate, and iron-related scales. The high level of dissolved iron commonly present in the water adversely affects the ability of the scale inhibitor to inhibit calcium carbonate scale. In this study, the inhibition performance of two new chemicals and some commercial products was evaluated under static and dynamic test conditions using synthetic Marcellus waters at varying iron concentrations. It was shown that both new chemicals were able to control calcium carbonate scale effectively in the presence of dissolved iron up to 200 ppm, whereas the performance of polycarboxylic acid, amino tri(methylene phosphonic) acid, and carboxymethyl inulin dropped sharply even in the presence of small amounts of Fe2+ (5 ppm). The inclusion of iron-sequestering agents with these chemicals and the effect of iron upon calcium sulfate inhibition are also discussed in this paper.
Acrolein Provides Benefits and Solutions to Offshore Oilfield-Production Problems
Authors: Horaska Darin , San Juan Claudia , Dickinson Allen , Lear Stephen , Colquhoun Alec
Published: March 2015

Offshore production systems can be impacted negatively by numerous problems attributed to bacterial activity, associated hydrogen sulfide (H2S) and biogenic iron sulfides (FexSy), and mercaptan (R-SH) production. Examples of these problems include microbiologically influenced corrosion (MIC); underdeposit corrosion because of FexSy deposition; equipment fouling because of biomass accumulation; impaired oil/water separation, leading to poor water quality and overboard oil-in-water problems; and not achieving pipeline specification because of excess H2O and/or R-SH content.

Acrolein provides a distinctive all-in-one chemical solution to assist in resolving these problems. The key to this solution is four-fold: Acrolein scavenges H2S, it scavenges R-SH, it is a potent microbiocide, and it dissolves FexSy.

This paper details the use of acrolein in the context of an offshore application with respect to the issues and problems unique to an offshore environment. Acrolein treatment programs can provide effective production-odor control and can achieve pipeline specifications from the perspective of H2S and R-SH scavenging. The unique dual solubility of acrolein in oil and water enables it to penetrate and remove oil-coated FexSy solids and sessile bacteria from production systems. Because of its low minimum-inhibitory concentration, acrolein provides cost-effective biocide treatment not only in batch applications but also in continuous-treatment programs. Well-established application protocols using a closed delivery system minimize potential chemical exposure, an important health, safety, and environment (HSE) consideration. The high order of reactivity and biodegradability of acrolein lends itself well to usage in a sensitive offshore environment.

A series of case histories highlighting the benefits of using acrolein in offshore systems to mitigate related production problems is presented in this paper. Multiple benefits can be realized with the application of one product.
Comparison of Multiphase Pumping Technologies for Subsea and Downhole Applications
Authors: Hua Gong , Falcone Gioia , Teodoriu Catalin , Morrison Gerald
Published: March 2015

The selection criteria for multiphase boosting options remain somewhat subjective and are frequently influenced by the vendors? data, which may mask potential limitations of this emerging technology. Existing literature on multiphase pumping tends to focus on a certain pump type for a specific field application, but does not provide more-generalized criteria for the selection of multiphase boosting solutions from among those available in the market. A comprehensive literature review into the working principles of the major pump types identified the intrinsic advantages and limitations of each technology for subsea and downhole applications.

The survey showed that, for subsea application, both the twin-screw pump (TSP) and the helicoaxial pump (HAP) can handle high suction gas volume fraction (GVF) with a fluid recycling system, or flow mixer. Thus, GVF is not a discriminating factor. The positive-displacement principle allows TSPs to work with very low suction pressure, but limits their operating range because of the dependency of flow rate on their relatively low speed. However, these pumps can handle highly viscous fluid. The rotodynamic concept enables the differential pressure of HAPs to self-adjust to any instantaneous change in suction GVF, and to achieve higher flow rate if sufficient suction pressure is maintained. Because HAPs usually run at higher speed, they offer a wider operating range.

For subsea application, HAPs appear to be a better option than TSPs because they offer higher operation flexibility and have a better installation track record.

For downhole applications, the electrical submersible pump (ESP) and the progressing-cavity pump (PCP) are the outstanding favorites, with the latter being preferred for lifting streams that are viscous or with high sand content. For GVF up to 70%, the rotodynamic pump (RDP) is becoming a popular solution. Although it is claimed that the downhole TSP (DTSP) can handle up to 98% GVF, it is not yet widely accepted in the field.
Prediction of Heavy-Oil Viscosities With a Simple Correlation Approach
Authors: Bahadori Alireza , Mahmoudi Mahdi , Nouri Alireza
Published: March 2015

Heavy-oil development is becoming increasingly important because of the continuous decline in conventional-oil production. For heavy-oil reservoirs, the oil viscosity usually varies dramatically during production processes such as in thermal processes. When producing heavy oil, the high viscosity is a major impediment to recovery. Oil viscosity is often correlated directly to the reserves estimate in heavy-oil formations and can determine the success or failure of a given enhanced-oil-recovery scheme. As a result, viscosity is an important parameter for performing numerical simulation and determining the economics of a project. In this work, a simple-to-use correlation has been developed to correlate the viscosity of heavy oil to temperature and to a simple correlating parameter that can be used for heavy-oil characterization. The reported results are the product of the analysis of heavy-oil data collected from the open literature for various heavy-oil fields around the world. The tool developed in this study can be of immense practical value for petroleum engineers, providing a method for quick assessment of the viscosity of heavy oils. In particular, petroleum and production engineers would find the proposed correlation to be user-friendly, with transparent calculations involving no complex expressions. The new proposed correlation shows consistently accurate results. This consistency could not be matched by any of the widely accepted existing correlations within the investigated range. For all conditions, the new correlation provided better results than existing correlations in the literature.
Considerations for the Application of Controlled In-Situ Burning
Authors: Mabile Neré J.
Published: March 2015

The burning of oil in place (in situ) on water is a viable means of mitigating the impact of marine oil spills. This paper defines three phases of decision-making, prioritizes the key issues of each phase, and proposes a process for analyzing the issues when considering controlled in-situ burning as an early response option in both icy and warm conditions. Also provided is a fact-based consideration of safe practices, such as those involving potential personnel exposure, sealife exposure, ignition control, fire control, and vessel safety. Controlled in-situ burning (ISB) can be initiated on a pre-approved or case-by-case basis, and there is generally a short operational time window during which it can be effectively used; therefore, quick, informed decision-making is imperative. This paper provides a discussion of these factors, along with a knowledge base of best practices that includes general categories of considerations, decision-making support tools, and specific operational approaches. The Deepwater Horizon response is used to illustrate both the operational approaches and the three decision-making phases; however, every situation is different and calls for decisions based on the individual circumstances. Because of its long history of research, testing, and use during spills, as well as positive environmental tradeoffs, controlled ISB is now considered by many to be a conventional response option.
Hydrate Risk Assessment and Restart-Procedure Optimization of an Offshore Well Using a Transient Hydrate Prediction Model
Authors: Zerpa Luis E. , Sloan E. Dendy , Koh Carolyn , Sum Amadeu
Published: March 2015

A produced-hydrocarbon stream from a wellhead encounters formation of solid gas-hydrate deposits, which plug flowlines and which are one of the most challenging problems in deep subsea facilities. This paper describes a gas-hydrate model for oil-dominated systems, which can be used for the design and optimization of facilities focusing on the prevention, management, and remediation of hydrates in flowlines. Using a typical geometry and fluid properties of an offshore well from the Caratinga field located in the Campos basin in Brazil, the gas-hydrate model is applied to study the hydrate-plugging risk at three different periods of the well life. Additionally, the gas-hydrate model is applied to study the performance of the injection of ethanol as a thermodynamic hydrate inhibitor in steady-state flow and transient shut-in/restart operations. The application of the transient gas-hydrate model proved to be useful in determining the optimal ethanol concentration that minimized the hydrate-plugging risk.
Computational Fluid Dynamics-Based Study of an Oilfield Separator--Part II: An Optimum Design
Authors: Pourahmadi Laleh Ali , Svrcek William Y. , Monnery Wayne
Published: March 2015

This paper provides details of comprehensive computational-fluid dynamics (CFD)-based studies performed to overcome the separation inefficiencies experienced in a large-scale three-phase separator. It will be shown that the classic design methods are too conservative and would result in oversized separators. In this study, effective CFD models are developed to estimate the phase-separation parameters that are integrated into an algorithmic design method to specify a realistic optimum separator. The CFD simulations indicated that noticeable residence times are required for liquid droplets to penetrate through the interfaces, and liquid droplets would be entrained again from the liquid/liquid interface vicinity by the continuous liquid phase.
Engineering Aspects in the Design and Implementation of Onshore Smart Oil Fields
Authors: Hafez Mohamed , Jakeman Simon , Al Azawi Bahir , Ur-Rahim Ihtisham , Khaled Moutaz
Published: March 2015

The smart-field concept is deployed through disseminating elements of toolsand infrastructure integrated to bring a level of smartness that can improvethe performance of an oilfield asset in a sustainable way. The design andimplementation of these tools and infrastructure's underpinning smartness candiffer on the basis of oilfield conditions. Greenfields, for example, can beengineered upfront to leverage all tools and deliver smart-field value from thebeginning of the asset's life. On the other hand, smart-field tools andinfrastructure for brownfields would be designed selectively and be implementedon the basis of several engineering and economic considerations.

The main functionalities of onshore smart field are remote operation,real-time information, and collaboration realized by the following tools andinfrastructure:

Subsurface permanent downhole gauges (PDHGs)

Subsurface flow controls

Wellhead instrumentation

Telecommunications infrastructure

Supervisory control and data acquisition (SCADA) and control system

Field-to-headquarters (HQ) connectivity

Collaboration work environment (CWE)

This paper outlines the engineering aspects to be considered in theselection, design, and implementation of tools and infrastructure for onshoresmart fields.
Flotation, Filtration, and Adsorption: Pilot Trials for Oilfield Produced-Water Treatment
Authors: Al-Maamari Rashid S. , Sueyoshi Mark , Tasaki Masaharu , Okamura Kazuo , Al-Lawati Yasmeen , Nabulsi Randa , Al-Battashi Mundhir
Published: March 2015

As an oil field matures, it produces larger quantities of produced water. Appropriate treatment levels and technologies depend on a number of factors, such as disposal methods or usage aims, environmental impacts, and economics. In this study, a pilot plant with a capacity of 50 m3/day was used to conduct flotation, filtration, and adsorption trials for produced-water treatment at a crude-oil gathering facility. The flexible design of the plant allows for the testing of different combinations of these processes on the basis of the requirements of the water to be treated. The subject water during this study was a complex and changing mixture of brine and oil from different oil fields. Induced-gas-flotation (IGF) trials were conducted, with different coagulant [poly-aluminum chloride (PAC)] -addition rates from 0 to 820 mg•L-1. Inlet-dispersed oil-in-water (OIW) concentrations were quite varied during the trials, ranging from 39 to 279 mg•L-1 (fluorescence-analysis method). Turbidity also varied, ranging from 85 to 279 FTU. Through coagulation/flocculation and flotation, dispersed oils were removed from the water. PAC addition ranging from 60 to 185 mg•L-1 resulted in the reduction of the dispersed-oil concentration to less than 50 mg•L-1 in treated water; and PAC addition ranging from 101 to 200 mg•L-1 resulted in the reduction of the dispersed-oil concentration to less than 15 mg•L-1 in treated water. Turbidity was also reduced through flotation, with trial average reductions ranging from 57 to 78%. Filtration further reduced turbidity at rates greater than 80% through the removal of any suspended solids remaining from flotation. Activated-carbon adsorption reduced OIW concentrations of flotation-/filtration-treated water to 5 mg•L-1 (infrared-analysis method) through the removal of dissolved oil remaining in the water. Results confirmed that such adsorption treatment would be more practical for water with lower chemical-oxygen-demand (COD) concentration because high-COD concentrations in water reduce the lifetime of activated carbon dramatically.
Integrity Maintenance of Petroleum Pipelines
Authors: Dawotola Alex , van Gelder P.H.A.J.M , Vrijling J.K
Published: March 2015

In this paper, a data-driven model is applied to derive optimum maintenance strategy for a petroleum pipeline. The model incorporates structured expert judgment (classical model) to calculate the frequency of failure, considering various failure mechanisms. Optimization models are applied to derive optimum maintenance intervals for petroleum pipelines on the basis of the frequency of failure estimated. Two separate maintenance-optimization models are proposed. The first is a use-based optimization model that minimizes the expected total cost from a petroleum pipeline. The second is a benefit/cost (B/C) -ratio model that seeks to maximize the benefit derived from the pipeline, while minimizing operation and failure costs. The B/C-ratio model is less data intensive, and it has been used to optimize failure data obtained in the classical model. In this approach, the maintenance optimization is a further attempt at reducing the influence of subjectivity in maintenance decisions.
Available Methodologies Concerning the Treatment and Removal of Sand From Pipelines and Associated Case Studies
Authors: Mackay Neil
Published: March 2015

Traditional sand-management programs usually consist of several measures employed to mitigate the production of sand from wells, a process commonly referred to as sanding. Such systems include production prediction and monitoring, topside management, sand control, and "intelligent" systems (Gherryo et al. 2009). Sand control can be considered in terms of short- and long-term solutions; examples of long-term solutions (preventative measures) would be the application of gravel packs, screens, inflow control devices, and chemical stabilization methods (Abney et al. 2007). In instances where a sand-management program has not been employed or has been ineffectively delivered, sand can and is deposited in pipelines/riser systems. This can be a gradual process of continual minor deposition over time, or systems can be overwhelmed with a sudden influx of sand as a consequence of formation or completion failure. The result leads to increasing pipeline resistance, reduced flow rates, rising pressure drop in the pipeline system, and erosion, which, in turn, can lead to degradation of the pipeline/riser and topside systems (Abney et al. 2007). The main focus then concerns the short-term sand-control solution of remediating the pipeline system with the goal of removing the deposits. An operator might wish to pursue a sand-removal/cleaning program with the specific goal of performing an in-line inspection as part of an integrity-management scheme.

This paper discusses the available methodologies for remediation of a pipeline affected by sand and presents examples where the discussed methodologies have been applied.