bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanical Alteration of Near-Wellbore Mineralogy for Improved Squeeze Performance
Authors: Fleming N.. , Ramstad K.. , Hoeth L. Wichers , Kidd S..
Published: August 2010

Squeezing of clean, high-permeability reservoirs frequently results in relatively short treatment lifetimes because of the low inhibitoradsorption rates achieved. One of the main controls on inhibitor retention is near-wellbore mineralogy. Clay-rich reservoirs that contain abundant kaolinite, for example, often have long squeeze lifetimes because enhanced inhibitor adsorption can occur on the clay surface. The occurrence of calcium carbonate (CaCO3) cement in the near-wellbore region can also enhance inhibitor retention by forming a Ca2+/inhibitor complex.

Previously published research (Fleming et al. 2009a) demonstrated the potential to mechanically alter the near-wellbore region through incorporation of low concentrations of kaolinite and organosilane. The data presented in the present work show that the additional incorporation of calcium carbonate provides a step change in the potential squeeze lifetimes achieved. This paper will present the results of using low, nondamaging concentrations of kaolinite and calcium carbonate particles in the preflush followed by scale inhibitor and organosilane in the main treatment. The kaolinite particles are retained in the near-wellbore region by the organosilane and enhance the number of potential sites for inhibitor adorption. At the same time, dissolution of the calcium carbonate particles by the acidic scale inhibitor forms a Ca2+/inhibitor complex that further enhances inhibitor retention.

A review of the technology performance envelope has been made through coreflooding that includes optimizing the concentration of injection particles vs. permeability, the ratio of injected kaolinite to carbonate particles, and performance at elevated temperature (175°C) along with an assessment of how often a well would require retreatment with particles. The latter has involved successive coreflooding of the same plug with the full treatment package followed by brine flowback and retreatment with scale inhibitor alone or with organosilane. This information can be used by the assets in their evaluation on potential use of the technology.
Injection of Water Above Gas for Improved Sweep in Gas EOR: Nonuniform Injection and Sweep in 3D
Authors: Jamshidnezhad Mohammad , van der Bol L.. , Rossen W.R.. R.
Published: August 2010

In gas-injection enhanced oil recovery (EOR), simultaneous injection of water and gas from parallel horizontal wells with water injected from the upper well [sometimes called modified simultaneous water and gas (SWAG) injection], can give deeper penetration of gas before gravity segregation than SWAG from the same well. Most previous studies of this process were limited to 2D, in which the injection rate is uniform along each well.

In 3D, we find that gas injection can be far from uniform, even in homogeneous reservoirs—which are the focus of this study. If gas injection is nonuniform in homogeneous reservoirs, it surely would be so in heterogeneous reservoirs. In some cases, there is an inherent instability in uniform injection along the gas well, even as the water well continues to inject nearly uniformly along its length. In our results, the uniformity of gas injection increases with increasing total injection rate and decreasing vertical distance between gas- and water-injection wells. The instability leading to nonuniform injection depends on the relation between gas saturation and gas relative permeability; we speculate that effects of gas flow on hydrostatic pressure, and therefore on gas-injection pressure, may also play a role. We find that in some cases, lateral movement of gas from the injection point partially mitigates the effects of nonuniform gas injection. Injecting gas from separate, independent segments along the horizontal well improves sweep somewhat by increasing the number of points at which gas exits the well.
Simulation and Optimization of Trapping Processes for CO2 Storage in Saline Aquifers
Authors: Nghiem Long , Shrivastava Vijay , Kohse Bruce , Hassam Mohamed , Yang Chaodong
Published: August 2010

This paper describes the modeling of the main processes for CO2 trapping in saline aquifers, namely solubility trapping, residual gas trapping and mineral trapping. Several important aspects of CO2 storage are presented. It has been found that the total amount of CO2 trapped as a soluble component, and as residual gas, can be enhanced by injecting brine above the CO2 injector. An optimization technique is used to adjust the location and rate of the brine injector to maximize the total amount of CO2 trapping. The security of the trapping process is then evaluated by taking into account the leakage of mobile CO2 through the caprock. For long-term CO2 storage, the conversion of CO2 into minerals is found to depend on the pre-existing minerals in the aquifer that provide the necessary ions for the reactions to occur.
Diffusivity of Citric Acid During its Reaction With Calcite
Authors: Alkhaldi Mohammed H. , Sarma Hemanta K. , Nasr-El-Din Hisham A.
Published: August 2010

The mass transfer process during the reaction of citric acid with calcite was investigated using a rotating disk apparatus. The effects of disk rotational speed, initial citric acid concentration and temperature on the effective diffusion coefficient of citric acid were examined.

Using various citric acid concentrations (1 wt%, 2 wt%, 5 wt% and 7.5 wt%), the diffusion coefficient of citric acid was calculated at 25°C, 40°C and 50°C. The effective diffusion coefficient of citric acid was found to be a function of the interplay between the calcium citrate precipitation and the presence of the counter-calcium ions. At high-initial acid concentration (5 wt% and 7.5 wt%), the effects of calcium citrate precipitation and counter-calcium ions were significant and the calculated citric acid diffusion coefficients were not comparable with those obtained using the rotating disk. However, the effects of both the calcium citrate precipitation and the counter-calcium ions on the citric acid diffusivity were minimal at low-initial citric acid concentrations.

The effect of temperature on the diffusion coefficient of citric acid at a constant citric acid concentration was found to follow Arrhenius law, and the activation energy was 37.9 kJ/mol.
A Method for Estimating Hydrocarbon Cumulative Production Distribution of Individual Wells in Naturally Fractured Carbonates, Sandstones, Shale Gas, Coalbed Methane and Tight Gas Formations
Authors: Aguilera Roberto
Published: August 2010

A method, based on factual observations of naturally fractured reservoirs in several countries, is presented for estimating distribution of hydrocarbon cumulative production in wells drilled in fractured reservoirs of Types A, B or C. These observations indicate that in reservoirs of Type C, most of the cumulative production is provided by just a few wells, while the majority of the wells contribute a small part of the reservoir cumulative production. In reservoirs of Type B, the number of wells contributing significantly to cumulative production becomes larger relative to the case of Type C reservoirs. Finally, in reservoirs of Type A, a large number of wells contribute to field production, as compared with Type B reservoirs.

The method is shown to be useful for tackling problems of practical importance in naturally fractured reservoirs, including performing or not performing infill drilling, estimating the variation in cumulative hydrocarbon production per well in a given reservoir and estimating the number of wells that might be required for a given field hydrocarbon recovery. The method is illustrated using data from various fractured reservoirs, including the Barnett shale and sandstone reservoirs in the United States, carbonate reservoirs in Mexico and Venezuela and coalbed methane reservoirs and tight gas sands in Canada.
Reservoir Modelling of Complex Geological Systems--A Multiple-Point Perspective
Authors: Eskandari Kiomars , Srinivasan Sanjay
Published: August 2010

Accurate characterization of sub-surface oil reservoirs is an essential prerequisite to the design and implementation of enhanced oil recovery (EOR) scenarios. Specifically, in reservoir characterization, integrating static and dynamic data into reservoir models to construct accurate and realistic models has received considerable attention. Unlike most of the conventional geostatistical approaches of integrating data into reservoir models that are based on semi-variograms (two-point statistics) as a measure of spatial connectivity, a complete multiple-point (MP) statistic framework is presented in this paper. In contrast to two-point statistic methods, MP statistics-based methods are capable of reproducing curvilinear geological structures. The algorithm starts with extracting MP statistics from training images (TI) using an optimal spatial template. After collecting different patterns and building the MP histogram, the pattern reproduction process commences. This process begins from data locations and then grows to fill the whole reservoir domain. The algorithm accounts for three main practical issues: uncertainty in geological scenarios, scanning template and non-stationarity. The MP statistics algorithm (growthsim) is capable of integrating data from multiple data sources. Among these data types is dynamic data or flow history.

The conventional approach to integrate production information into reservoir models is by iterative perturbation of the reservoir model until the production history of the reservoir is matched. Iterative methods have been applied till date to random fields that are completely characterized by a two-point co-variance function. In contrast, this paper presents a forward modelling approach that investigates history matching within a MP modelling framework. A novel technique implemented in this research is based on the merging of MPs inferred from history matched and geological models. Pattern growth is performed subsequently by sampling from the merged MP histograms. History matched models using the presented approach show an excellent agreement with underlying geological descriptions and match production history.
Valuation of Oil Properties
Authors: Sheldon Dean H.
Published: August 2010

Introduction

Those of the oil industry, who are concerned with the earning power of oilproducing properties, visualize a valuation report as a rather stereotypedpresentation of data in a form that engineers use to present the results of ananalysical engineering appraisal. Specifically an engineering appraisal is anestimate of future recoverable oil and the cash profit to be derived from theproduction and sale of that oil. It should present with clarity the differencebetween factual material and the opinions formed from the analysis of thatmaterial. In presentation the engineer should keep in mind the purpose of theappraisal and the background of the people to whom the report is addressed.

Factors Considered

The fundamental features of an engineering appraisal for oil producingproperties are:

The type of interest in oil production that is being appraised and thecontents of the documents which create the interest.

The acquisition of data on the physical aspects of the oil reservoir and theincome and expenses that are connected with the removal and marketing of theoil and its associated hydrocarbons and the use of such information to forecastthe probable future earnings of the property.

There are many types of interest that may exist in a piece of oil producingland. There is a mineral interest; a landowner's interest, an overridingroyalty interest, an operating or lessee interest, sometimes called the workinginterest, a carried working interest, and a participating interest.

Each has a distinctive character determined by the wording of the legaldocument or contracts which create and transfer its ownership from party toparty. Careful consideration of all the terms of a lease and their effect onthe earning power of an oil property from a lessor and lessee's point of viewis not feasible. Nor is it proper to attempt a review of the effect manyfeatures of operating agreements and assignments may have on the worth ofvarious interests in oil production. A brief examination of some of the termscommonly found in various contracts concerning oil properties might be ofinterest to engineers.
Covered Grains in Naked Oat: Environment and Herbicide Effects
Authors: Lanoie Nathalie , Vanasse Anne , Collin Jean , Reid Judith Frégeau , Pageau Denis , Lajeunesse Julie , Durand Julie
Published: August 2010

Naked oat (Avena sativa L.) grown in Québec, Canada, produces an average of 10% covered grains. The objectives of this study were to evaluate the effects of environment, herbicide, and genotype on the proportion of covered grains, to study the relation between the presence of awns and the proportion of covered grains, and to determine the location of covered grains on the plant (tiller) and on the panicle. Eight oat lines were evaluated over 2 yr at four experimental sites. Each line was treated with bromoxynil/MCPA, dicamba/MCPA, or thifensulfuron methyl/tribenuron methyl applied at Zadoks 12–13 and compared to a hand‐weeded check. The highest percentages of covered grains, 5.5 and 6.9%, were found at different sites in 2006 and 2007. The application of dicamba/MCPA increased the percentage of covered grains in the lines normally producing a higher proportion of covered grains, but low producing lines were less affected. Minor differences were found among the other weed control treatments. No relation was found between the presence of awns and the proportion of naked grains. Covered grains were mostly produced on the main stem and their position on the panicle depended on genotype and weed control treatment.
Agronomic and Seed Characteristics of Soybean Lines with Alleles for Modified Glycinin Concentration
Authors: Jenkinson Jonathan E. , Fehr Walter R.
Published: August 2010

Soybean [Glycine max (L.) Merr.] genotypes have been developed with increased β‐conglycinin (BC) and reduced glycinin to improve the quality and health benefits of food products containing soybean protein. The changes in protein composition are due to the five recessive alleles, gy1, gy2, gy3, gy4, and gy5, that modify glycinin concentration. The objective of this study was to evaluate the influence of the gy alleles on protein composition and agronomic traits. Nineteen lines in each of eight genotypic classes involving different combinations of gy alleles from five populations were evaluated for protein composition, seed yield, and maturity in 2008.The BC concentration of lines was maximized with the gy1,2, gy4, and gy5 alleles, but the gy3 allele also was required to obtain 0 g kg−1 of glycinin. The effect of the recessive alleles on the increase in BC concentration was greatest for gy1,2 (98 g kg−1), intermediate for gy5 (44 g kg−1), and least for gy3 (18 g kg−1). There were significant differences in mean protein and oil concentration, grain yield, and maturity among the eight genotypic classes; however, the differences were not consistent among the populations. It should be possible to develop soybean cultivars with increased BC and decreased glycinin concentration that have protein and oil concentration, grain yield, and maturity similar to cultivars with normal protein composition.
Genetic Diversity of Andean Tuber Crop Species in the in situ Microcenter of Huanuco, Peru
Authors: Malice M. , Bizoux J. P. , Blas R. , Baudoin J. P.
Published: August 2010

Andean tuber crop species oca (Oxalis tuberosa Molina), ulluco (Ullucus tuberosus Caldas), and mashua (Tropaeolum tuberosum Ruiz & Pav.) play major roles in Andean communities. These species show high variability but are threatened with genetic erosion. To study the management of genetic resources of neglected vegetatively propagated crop species, we studied genetic diversity and structure of these species in an in situ diversity microcenter (Huanuco, Peru). A sample of 15 varieties of oca, 15 of ulluco, and 26 of mashua was analyzed with the inter simple sequence repeats (ISSR) molecular markers. Mean genetic distances and global genetic diversities were high for the three species, with higher values for mashua than for oca and ulluco. Assignment technique divided both oca and ulluco samples into two genetic clusters; the mashua sample probably belongs to a single genetic cluster. Inter simple sequence repeats (ISSR) technique showed intravarietal genetic variability for most varieties, suggesting an underestimation of the in situ genetic variability. These results are discussed considering how variation in breeding systems and farmers' practice influenced patterns of genetic diversity. Our findings confirm the hypothesis of a considerable amount of variability found in neglected Andean tubers and are essential to deserve adequate conservation strategies and to maintain genetic resources of neglected Andean tuber crop species under a threat of genetic erosion.
Root Characteristics of Two Soybean Cultivars Grown in Fumigated Fields in Iowa
Authors: Murillo‐Williams Adriana , Kaspar Tom C. , Pedersen Palle
Published: August 2010

Soybean [Glycine max (L.) Merr.] yield is often limited by root‐infecting pathogens, mainly soybean cyst nematode (SCN; Heterodera glycines Ichinohe). The objective of this experiment was to evaluate differences in root characteristics and yield of NK‐S25J5 (SCN‐susceptible) and IA2068 (SCN‐resistant) soybean cultivars at three locations (De Witt, Nevada, and Whiting) in Iowa, in fumigated vs. nonfumigated soil. A 2‐ha section of a field was fumigated each year with Telone‐35. Root sampling was conducted at 21, 42, and 63 d after emergence (DAE). Initial SCN population densities (Pi) were 4790, 2590, and 825 eggs 100 cm−3 soil for De Witt, Nevada, and Whiting, respectively. Under the conditions of this experiment, there was no evidence of a decrease in Pi caused by fumigation. Fumigation was associated with an increase in final SCN population (Pf), a reduction in yield of NK‐S25J5 by 560 kg ha−1 at De Witt, and at 42 DAE, with an increase in root length density (RLD), and root surface area (RSA). The highest yields were obtained at Whiting, the location where the greatest Pf/Pi was observed for NK‐S25J5. Average yields for IA2068 and NK‐S25J5 were 4745 kg ha−1 and 3665 kg ha−1, respectively. We concluded that greater RLD could be the result of complex modifications of the environment where roots grow, mainly microbial populations, including SCN. Stress caused by SCN was associated with a decrease in yield in the susceptible cultivar.
Soybean Reproductive Sink Size and Short‐term Reductions in Photosynthesis during Flowering and Pod Set
Authors: Egli D. B.
Published: August 2010

The number of pods and seeds produced by soybean [Glycine max (L.) Merr.] is related to canopy photosynthesis during flowering. The effect of low photosynthesis during only a portion of flowering (growth stage R1 to R5), however, is not well defined. Two field experiments were conducted at Lexington, KY (38°N), with seeds sown in mid‐May in 0.76‐m rows (20 seeds m−1 of row) and all plots irrigated as needed. In 2005/2006, plants (cultivars Pennyrile and Ripley) were shaded (60% in 2005 and 80% in 2006) for 4‐ to 9‐d periods just before or just after peak pod production. These treatments had almost no effect on seed number (significant reduction in only one of eight comparisons). In a second experiment (cv. Pennyrile, 2007/2008), shade cloth (60%) was placed over plants at growth stage R1.6 and removed at 7‐d intervals. The first 7 d of shade did not affect seed number, but 14 d of shade ending at roughly growth stage R3.0 reduced seed number by 16% and longer periods caused proportionally larger reductions. When shade cloth (80%) was put in place at 7‐d intervals (starting at R3.4) and left in place until maturity, seed number was reduced until the last treatment (put in place 4–7 d after the beginning of growth stage R6). Seed number was tolerant of short periods (4–9 d) of low assimilate supply during flowering, but could not recover from longer periods of shade (≥14 d), even when they occurred relatively early in the flowering period.
A New PCR‐Based Linkage Map in Pearl Millet
Authors: Pedraza‐Garcia F. , Specht J. E. , Dweikat I.
Published: August 2010

Pearl millet [Pennisetum glaucum (L.) R. Br.] is a multipurpose cereal grown for grain, stover, and green fodder. Relative to other cereal species, it ranks sixth in annual world production. Use of molecular marker technology for pearl millet genetic improvement has been limited because of an insufficiently developed linkage map. The majority of the pearl millet molecular markers (RFLP and SSR) mapped to date are clustered around the seven pearl millet chromosome centromeres, and only a few marker loci are mapped to more distal regions. There is a need for more evenly distributed markers throughout the linkage map and greater marker coverage of the gaps in earlier established maps. The objective of this research was to develop a PCR‐based molecular marker linkage map for pearl millet on the basis of a recombinant inbred line (RIL) population resulting from a cross between Tift 23DB and PI 536400. This mapping effort involved 152 RILs and 196 PCR‐based DNA markers (66 SRAPs, 63 RAPDs, 27 ISSRs, 31 pearl millet, 6 sorghum, and 3 maize SSRs). The average genetic distance between markers was 9.2 cM, varying from 0 to 25.6 cM. The number of markers in each linkage group (LG) ranged from 6 to 35. The resulting map consisted of nine linkage groups that spanned about 1796 cM. The majority of the markers used in this study to construct the genetic linkage map were randomly distributed in each LG, which makes it useful in pearl millet mapping and breeding.
Effect of Maturity on Seed Sugars as Measured on Near‐Isogenic Soybean (Glycine max) Lines
Authors: Bellaloui N. , Smith J. R. , Gillen A. M. , Ray J. D.
Published: August 2010

The objective of this study was to investigate the effect of maturity and field temperature on the concentration of sucrose, raffinose, and stachyose in soybean seed in two sets of near‐isogenic lines of Clark and Harosoy. The maturity of each line within each set varied, but all lines from each set shared a common genotypic background. The results showed that in the Clark isoline set, maturity had a negative linear relationship (sugars decreased as days to maturity increased) with the concentration of sucrose (r2= 0.83 in 2004;r2= 0.94 in 2005), stachyose (r2= 0.51 in 2004;r2= 0.51 in 2005), and combined sugars (sucrose+raffinose+stachyose) (r2= 0.83 in 2004;r2= 0.91 in 2005). In the Harosoy set, there were significant negative relationships between maturity and sugars only in 2005 for sucrose, stachyose, and combined sugars. In the Clark set, temperature had a significant positive relationship with sugars in 2004 (sugars increased as temperature increased), but significant negative relationship in 2005. In the Harosoy set, there was a significant negative relationship between field temperature and sugars only in 2005. The contribution of maturity to the total variation in sugars was significantly higher than temperature. It was concluded that the effect of genotypic background and maturity genes on sugar concentration depended on the type of sugar.
Postharvest Survey of Spring Wheat Fields Initially Assessed for Gene Flow
Authors: Hucl P. , Matus‐Cádiz M. A.
Published: August 2010

Recent research has addressed the potential for gene flow in wheat (Triticum aestivum L.). However, there is scant information on the fate of introgressed genes in the subsequent crop rotation. The objective of this study was to quantify spring wheat volunteers potentially arising from gene flow. A total of 152 wheat fields that had been used to measure gene flow at distances of up to 10 km were surveyed for blue aleurone volunteers for 3 yr postharvest. No blue aleurone seed was detected in samples from the 152 fields surveyed. A single blue aleurone volunteer plant was detected in a pollen donor field subsequently sown to wheat in the third year postharvest. The absence of blue aleurone wheat volunteers in the postharvest crop rotation was not unexpected as only four of the original 152 fields had shown evidence of gene flow. Under the environmental and crop management practices encountered in this study, the risk of a gene flow‐based adventitious event in spring wheat being detected at significant levels in subsequent crops appears low.
Development of Wheat Lines Having a Small Introgressed Segment Carrying Stem Rust Resistance Gene Sr22
Authors: Olson Eric L. , Brown‐Guedira Gina , Marshall David , Stack Ellen , Bowden Robert L. , Jin Yue , Rouse Matthew , Pumphrey Michael O.
Published: August 2010

The wheat stem rust resistance gene Sr22 confers resistance to Puccinia graminis f. sp. tritici Pers. race TTKSK (also known as Ug99) that developed in Africa and is an immediate threat to world wheat production. The resistance gene is present on a chromosomal translocation derived from Triticum boeoticum Boiss., which has a genome that is partially homologous to the A genome of T. aestivum L. Sr22 has been deployed in a limited number of cultivars due to poor agronomic performance of lines carrying the resistance gene. Linkage analysis of simple sequence repeat (SSR) markers on chromosome 7A was performed to identify loci closely linked to Sr22. The most tightly linked proximal and distal SSR marker loci were Xcfa2123 and Xwmc633, respectively. A two‐step process was then used to develop resistant lines having smaller chromosome segments derived from the diploid donor. First, individuals in which a single recombination event had occurred between wheat and the Sr22 introgression were identified in the mapping populations. In spite of reduced recombination between T. boeoticum and T. aestivum chromosomes, sufficient recombination events were found among 398 F3:4 lines derived from recombinant F2 progeny to recover multiple resistant individuals with smaller alien introgressions. Resistant lines were identified having less than 6% of the chromosome arm derived from T. boeoticum. These lines may provide a more agronomically desirable source of Sr22 that can be readily deployed in cultivars resistant to Ug99.
The Lack of Beta‐amylase Activity in Soybean Cultivar Altona sp1 is Associated with a 1.2 kb Deletion in the 5′ Region of Beta‐amylase I Gene
Authors: Kim Won‐Seok , Krishnan Hari B.
Published: August 2010

Previous studies have identified near‐isogenic soybean [Glycine max (L.) Merr.] lines, one containing normal β‐amylase [α‐1,4‐glucan maltohydrolase (EC 3.2.1.2)] activity (Altona Sp 1b) and the other with undetectable β‐amylase activity (Altona sp 1) in seeds. SDS‐PAGE analysis of 50% isopropanol extracted proteins from soybean seeds revealed a prominent 56 kDa protein. This protein, which was absent in Altona sp 1, was identified as β‐amylase by matrix‐assisted‐laser‐desorption‐time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) and immunoblot analysis using antibodies generated against Arabidopsis β‐amylase. Southern blot analysis showed differences in the sizes of the DNA fragments hybridizing to β‐amylase probe between the near‐isogenic soybean lines. A search of the soybean genome database revealed the presence of nine β‐amylase genes in the soybean genome. We have isolated the β‐amylase gene (GmBAM 1) by screening a genomic library of wild‐type soybean and determined its nucleotide sequence. Analysis of the nucleotide sequence of the GmBAM 1 revealed a complete open reading frame that was interrupted by six introns. In contrast, the GmBAM 1 from Altona sp 1 had a 1207 bp deletion near the 5′ region that included the second and third exon regions. Our results suggest that this deletion may be responsible for the lack of β‐amylase activity in soybean cultivar Altona Altona sp 1.
Soil Physical Properties of Aging Golf Course Putting Greens
Authors: Lewis J. D. , Gaussoin R. E. , Shearman R. C. , Mamo M. , Wortmann C. S.
Published: August 2010

United States Golf Association (USGA) specification putting greens are designed to limit excess soil water and compaction; but these soil properties change over time. Objectives were to define soil physical properties of sand‐ amended rootzones as affected by (i) rootzone mixture, (ii) establishment treatment, and (iii) putting green age. The USGA specification rootzones were built and established with Agrostis stolonifera L. in four sequential years. Rootzone treatments were 80:20 (v:v) sand and sphagnum peat and an 80:15:5 (v:v) sand, sphagnum peat, and soil. An accelerated establishment treatment applied 2.5, 3, and 2.5 times N, P, and K, levels, respectively, than the control treatment. Data were collected on rootzone particle size distribution and saturated hydraulic conductivity (Ksat), bulk density, total, air‐filled and capillary porosity for 8 yr, infiltration rate for 10 yr. All soil physical properties changed with age, but were not influenced by establishment treatment. Infiltration declined 73% but remained adequate (≥0.15 m h−1) for location precipitation. Capillary porosity and bulk density increased 32 and 7%, respectively, while air‐filled porosity decreased 38%. Capillary and air‐filled porosity still met USGA specification after 8 yr. Addition of soil to the sand‐based rootzone mixture had no negative effect on soil physical properties. Fine sand from topdressing and surface organic matter accumulation were thought to account for these changes.
Developing a Mini‐Core Collection in Finger Millet Using Multilocation Data
Authors: Upadhyaya H. D. , Sarma N. D. R. K. , Ravishankar C. R. , Albrecht T. , Narasimhudu Y. , Singh S. K. , Varshney S. K. , Reddy V. G. , Singh S. , Dwivedi S. L. , Wanyera N. , Oduori C. O. A. , Mgonja M. A. , Kisandu D. B. , Parzies H. K. , Gowda C. L. L.
Published: August 2010

Finger millet [Eleusine coracana(L.) Gaertn.], among small millets, is the most important food crop in some parts of Asia and Africa. The grains are a rich source of protein, fiber, minerals, and vitamins. A core collection of 622 accessions was developed. The aim of this study was to develop a mini‐core collection using multilocational evaluation data of the core collection. Six hundred and twenty‐two accessions together with six controls (four common and two location‐specific) were evaluated for 20 morphological descriptors at five agroecologically diverse locations in India during the 2008 rainy season. The experiment was conducted in α design with two replications at Patancheru and in augmented design with one of the six controls repeated after every nine‐test entry at other locations. The hierarchical cluster analysis of data using phenotypic distances resulted in 40 clusters. From each cluster, ∼10% or a minimum of 1 accession was selected to form a mini‐core, which was comprised of 80 accessions. The comparison of means, variances, frequency distribution, Shannon–Weaver diversity index (H′), and phenotypic correlations revealed that the mini‐core captured the entire diversity of the core collection. This mini‐core collection is an ideal pool of diverse germplasm for identifying new sources of variation and enhancing the genetic potential of finger millet.
Multivariate Patterns of Diversity in Ethiopian Barleys
Authors: Bjørnstad Asmund , Abay Fetien
Published: August 2010

Ethiopian barleys (Hordeum vulgare L.) have been collected and described since the early expeditions by Harlan and Vavilov in the 1920s. This paper reviews the literature since then on the diversity and distinctness in this germplasm based on different types of traits (e.g., morphology, isozymes, DNA markers, phenotypic screenings). Most studies have been based on one type of trait at a time. They all indicate that Ethiopian barleys form a very distinct group, with unique diversity in resistance to certain diseases and in morphology, but the average DNA marker or nucleotide diversity is substantially less than barley from the Fertile Crescent. The recurrent suggestions of Ethiopia as a center of origin for barley are discussed; most data support the notion of a “secondary” center. There is a paucity of studies of adaptive traits important to Ethiopian conditions or breeding. The major pattern of adaptation reflects the rainfall patterns, following an altitudinal gradient with increasing rainfall and longer growing season up to about 3000 m altitude. As barleys become later in maturity, they become more susceptible to net blotch, but tolerant to scald and probably frosts during grain maturation. Several improved cultivars have resulted from the pure line selection program initiated about 20 yr ago.
A Framework for Postrelease Environmental Monitoring of Second‐generation Crops with Novel Traits
Authors: Beckie Hugh J. , Hall Linda M. , Simard Marie‐Josée , Leeson Julia Y. , Willenborg Christian J.
Published: August 2010

As first‐generation genetically modified/transgenic crops with novel agronomic traits have been grown commercially in a number of countries since the mid‐1990s, second‐generation crops with novel traits (CNTs) are now being tested in confined field trials around the world. Postrelease monitoring (PRM) of abiotic stress–tolerant and other second‐generation CNTs will strengthen prerelease environmental risk assessments, for which protocols are being developed. We outline a comprehensive framework and protocol for case‐specific PRM of such CNTs in Canada, using drought‐tolerant canola (Brassica napus L.) as a model CNT. The primary potential environmental risk associated with cultivation of drought‐tolerant canola is increased invasiveness of volunteers or feral plants (self‐perpetuating populations) and weedy relative–crop hybrids or backcrossed progeny in ruderal (noncropped disturbed) and natural areas adjacent to CNT cultivation, resulting in loss of abundance or biodiversity of native plant species. Accurately predicting CNT invasiveness a priori is problematic, especially for traits that may enhance plant fitness and invasiveness. Thus, PRM can effectively address the greater uncertainties in the environmental risk assessment of these second‐generation vs. first‐generation CNTs and thereby enhance environmental protection and security of the food supply.
Turfgrass Characteristics of Prairie Junegrass Germplasm Accessions
Authors: Clark Matthew D. , Watkins Eric
Published: August 2010

Prairie junegrass [Koeleria macrantha (Ledeb.) Shultes] is a perennial, short‐grass prairie species distributed throughout the Northern Hemisphere. This species demonstrates tolerance to many environmental stresses in Minnesota. Forty‐eight K. macrantha accessions from the United States National Plant Germplasm System (NPGS) were grown under low‐input conditions to evaluate turfgrass quality characteristics for use in a breeding program. A second objective was to identify key geographical locations for germplasm collection. The experiment was conducted at Becker and St. Paul, MN. Nineteen accessions at Becker and 30 accessions at St. Paul performed with an adequate turf quality rating of 5.0 or higher when averaged over the 3‐yr study, suggesting the potential for use in low‐input areas. Prairie junegrass from northern collection regions displayed the highest spring green‐up ratings, an important turf trait in northern climates. There was a negative correlation between this trait and mowing quality at Becker (r = −0.44) and at St. Paul (r = −0.34). Several accessions had acceptable mowing quality and would be candidates for integration into a native prairie junegrass turfgrass breeding program. There was no correlation between inflorescence emergence and turf quality, or between inflorescence emergence and persistent straw suggesting that flowering does not necessarily affect turf quality ratings. Rust (unknown Puccinia species) was present at both locations.
Generation Means Analysis Using Mixed Models
Authors: Piepho H. P. , Möhring J.
Published: August 2010

This paper shows how to perform generation means analysis, including estimation of genetic variance components, by a mixed model package. The approach is exemplified with a small dataset, which is analyzed by the MIXED procedure of the SAS System and by ASReml. The proposed analysis accounts for between‐plot variation, which is often ignored. Also, heterogeneity of standard errors of mean contrasts due to unequal sample size per plot and nonconstant genetic variance can be properly reflected.
Thermodynamics of Supercritical Fluid Extraction of Some Dyes and Pharmaceutical Compounds Using the Weighting Matrix Approach
Authors: Al-matar Ali , Sweis Fawaz K.
Published: August 2010

Mixing rules play an important part in the ability of an equation of state to accurately model the behavior of various phases at equilibrium. Many mixing rules have been proposed in the literature. However, due to shortcomings of the mixing rules and/or the equation of state, binary interaction parameters have been introduced to improve the accuracy of models. This work proposes an alternative to binary interaction parameters based on a weighting matrix. It is demonstrated that for the Peng-Robinson EOS applied to prediction of the solubility of various species of industrial importance, such as dyes and pharmaceutical products in supercritical CO2, the weighting matrix approach performs slightly better than the binary interaction parameter while providing more flexibility in the model.
Agronomic characteristics of the spring forms of the wheat landraces (einkorn, emmer, spelt, intermediate bread wheat) grown in organic farming
Authors: Konvalina Petr , Capouchová Ivana , Stehno Zdeněk , Moudrý Jan
Published: August 2010

Agronomic characteristics of the spring forms of the wheat landraces (einkorn, emmer, spelt, intermediate bread wheat) grown in organic farming

Organic farmers look to the possibilities of growing neglected crops, such as the spring forms of hulled wheat - einkorn, emmer and spelt - for support in developing the organic farming system. In 2008, 169 landraces from the gene bank at the Crop Research Institute in Prague were tested on certified organic plots. The experiment was aimed at finding suitable varieties for the organic farming system. In summary, our findings show that einkorn (Triticum monococcumL.) and emmer wheat [Triticum dicoccumSchrank (Schuebl)] are resistant to powdery mildew and brown rust, spelt wheat (Triticum speltaL.) is less resistant to these two diseases, and the intermediate forms of bread wheat are very sensitive to such infestation. The varieties evaluated incline to lodging, as they have long and weak stems. Einkorn and emmer wheat have short and dense spikes and a low thousand grains weight, whereas spelt wheat has long and lax spikes. The level of the harvest index is low. Potentially useful varieties were found during the field experiment and evaluation, and our future efforts will therefore focus on improving resistance to lodging and increasing the productivity of the spike.
Viability and survival capability of quinolone-resistant uropathogenic Escherichia coli
Authors: Slavchev Georgi , Markova Nadya
Published: August 2010

Uropathogenic strains of E. coli isolated from urine of patients with urinary tract infections were tested for antibiotic sensitivity using bio-Merieux kits and ATB-UR 5 expression system. The virulence of strains was evaluated by serum bactericidal assay, macrophage “killing” and bacterial adhesive tests. Survival capability of strains was assessed under starvation in saline. The results showed that quinolone-resistant uropathogenic strains of E. coli exhibit significantly reduced adhesive potential but relatively high resistance to serum and macrophage bactericidity. In contrast to laboratory strains, the quinolone-resistant uropathogenic clinical isolate demonstrated increased viability during starvation in saline. Our study suggests that quinolone-resistant uropathogenic strains are highly adaptable clones of E. coli, which can exhibit compensatory viability potential under unfavorable conditions. The clinical occurrence of such phenotypes is likely to contribute to the survival, persistence and spread strategy of resistant bacteria.
Micropropagation of Vitis vinifera L. cv. ‘Malagouzia’ and ‘Xinomavro’
Authors: Skiada Fotini , Grigoriadou Katerina , Eleftheriou Eleftherios
Published: August 2010

The effects of six basal media on in vitro shoot proliferation of the greek grapevines Vitis vinifera L. cv. ‘Malagouzia’ and ‘Xinomavro’ were investigated. Galzy and Zlenco proved to be the most effective for ‘Malagouzia’ and ‘Xinomavro’, respectively. If only BA was present in the medium, shoot development was poor and the plantlets were chlorotic. When the medium was supplemented with BA and NAA, growth was enhanced. The best ratio (in μM) of growth regulators was 0.5/0.3 for ‘Malagouzia’, and 0.1/0.03 for ‘Xinomavro’, which resulted in the highest number of microshoots per explant and greatest proliferation rate. The development of ‘Malagouzia’ and ‘Xinomavro’ explants at 21±2 and 26±2°C was also investigated, revealing the higher temperature to be more effective. Regarding rooting, 0.5 μM IBA improved root formation at 26°C for ‘Malagouzia’ and 0.5 μM IBA at 21°C for ‘Xinomavro’. Moreover, 0.5 μM IBA resulted in a higher rooting percentage (>95%) and proved to be more beneficial for the overall morphological appearance of the plantlets of ‘Malagouzia’. After acclimatization, survival of microshoots cultivated in media with IBA was higher than those in NAA.
Modeling and Characterization of the Relationship between Cell Size and Mechanical Behavior of Microcellular PP/Mica Composites
Authors: Gong W. , Gao J. C. , Jiang M. , Yu J. , He L.
Published: August 2010

The microcellular foamed polypropylene (PP)/mica composites were prepared through chemical microcellular injection to investigate the relationship between the mechanical behavior and the cell size. The mechanical behavior model of the microcellular foams is built based on the elastic stress/strain field. The mechanical behavior of the microcellular composites coincides well with the theoretical model. Under loading the large and non uniform cells are in a state of plane strain, which leads to low tensile and impact strengths, whereas small and uniform cells are in a state of plane stress, which contributes to the transition from brittle to tough fracture behavior in the microcellular PP/mica composite.
Entry Flow of Polyethylene Melts in Tapered Dies
Authors: Ansari M. , Alabbas A. , Hatzikiriakos S. G. , Mitsoulis E.
Published: August 2010

The excess pressure losses due to end effects (mainly entrance) in the capillary flow of several types of polyethylenes were studied both experimentally and numerically under slip and no-slip conditions. These losses were first measured as a function of the contraction angle ranging from 15° to 90°. It was found that the excess pressure loss attains a local minimum at a contraction angle of about 30° for all types of polyethylenes examined. This was found to be independent of the apparent shear rate. This minimum becomes more dominant under slip conditions that were imposed by adding a significant amount of fluoropolymer into the polymer. Numerical simulations using a multimode K-BKZ viscoelastic model have shown that the entrance pressure drops can be predicted fairly well for all cases either under slip or no-slip boundary conditions. The clear experimental minimum at about 30° can only slightly be seen in numerical simulations, and at this point its origin is unknown. Further simulations with a viscous (Cross) model have shown that they severely under-predict the entrance pressure by an order of magnitude for the more elastic melts. Thus, the viscoelastic spectrum together with the extensional viscosity play a significant role in predicting the pressure drop in contraction flows, as no viscous model could. The larger the average relaxation time and the extensional viscosity are, the higher the differences in the predictions between the K-KBZ and Cross models are.
Rheological and Molecular Investigations of Polyethylene Degradation in a Batch Mixer
Authors: Twite-Kabamba E. , Rodrigue D.
Published: August 2010

In this study, polyethylene degradation is related to its thermo-mechanical history from processing in a batch mixer. A focus is made on the rheological and molecular properties of the polyethylene subjected to different processing conditions by changing the temperature, the rotor speed and the time of process. The results indicate that while shear rheological properties changed slightly, the elongational properties were substantially modified, especially the maximum stress and the elongation at break. Due to the formation of macroradicals while processing, macromolecular changes were characterized in terms of molecular weight distribution and the results represent a balance between rates of chain scission and chain branching. It was found that the main parameter to characterize the degradation behaviour was the input power.
Effect of Process Parameters on Mechanical Properties of Rice Husk Polypropylene Composites
Authors: Kumar V. , Sinha S. , Saini M. S. , Kanungo B. K.
Published: August 2010

Low density, easy of availability, less abrasive and biodegradable nature of lignocellulosic materials emphasized their usage for development of thermoplastic composites based on Rice Husk and Polypropylene (RHPP). Mechanical properties of RHPP composites such as tensile, impact strength decreases by the addition of rice husk, preheating of rice husk and its proper size is essential for its effective use as filler in polypropylene composites. Improvement in tensile, impact, hardness and abrasion resistance is possible by adding compatibiliser and reduction of cooling time. Impact strength of the composite increase with temperature, optimum temperature for obtaining good tensile, hardness and abrasion is 200°C. RHPP Composites thus prepared have potential for applications in building and automobile industries.
Coordination of Design Contract with Construction Manager-at-Risk Preconstruction Service Contract
Authors: Shane Jennifer S. , Gransberg Douglas D.
Published: August 2010

A recent NCHRP study found that seven state departments of transportation (DOTs) have some type of experience using construction manager-at-risk [(CMR), also termed construction manager–general contractor (CM-GC)] project delivery. This project delivery method's major advantage was observed to lie in the collaboration between the designer and the builder during the preconstruction phase, which was found to reduce delivery time and project costs. Preconstruction collaboration does not happen automatically in CMR project delivery. To be effective, the requirement to collaborate must be included in both the design and preconstruction services contracts. This paper reports on changes to DOT design contracts successfully employed in CMR transportation projects. It concludes that an agency's standard design services contract must be modified to coordinate directly with the CMR preconstruction services contract to maximize the benefits associated with this project delivery method.