bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of the LOX and GOX Systems for the Stennis Space Center High Heat Flux Facility
Authors: Yentzen MJ
Published: March 2009

The High Heat Flux Facility (HHFF) was designed to test the high temperature performance of materials for the National Aerospace Plane (NASP) by directing the exhaust of several gas generators at actively cooled panels of the test materials. To accomplish this, a supply of high pressure gaseous oxygen (GOX) is required to feed the gas generators. In addition, a low pressure liquid oxygen (LOX) loading, storage, and supply system is required. The low pressure LOX system was designed for a maximum operating pressure of 722 KPa (90 psig) for the loading area and 1 135 KPa (150 psig) for the storage portion. A pump increases the operating pressure of the LOX from approximately 1 135 KPa (150 psig) to a maximum of 31.13 MPa (4 500 psig). An ambient air vaporizer converts the high pressure LOX to GOX. The high pressure GOX system was also designed for a maximum operating pressure of 31.13 MPa (4 500 psig).

This paper discusses the approach used for designing and constructing the LOX and GOX systems for the HHFF. Stennis Space Center and NASA requirements for the use of materials in oxygen systems are discussed. Particular emphasis is placed on the materials of construction and the selection of materials for the high pressure GOX components, piping, and other hardware. Several examples of actual components modified for use in oxygen are illustrated and the rationale used for selecting piece part materials for these components are provided. The system design philosophy is discussed and several general oxygen system design principles are mentioned. Specific portions of the design intended to reduce the likelihood of ignition are also addressed. Drawings of the systems and components are included to provide more specific information that could be used as a model for the design of similar systems.
New Test Capabilities for the Evaluation of Material Flammability in Oxygen-Enriched Atmospheres
Authors: Steinberg TA , Scown BC
Published: March 2009

Recent work within the Department of Mechanical Engineering at The University of Queensland has led to the development of a new test system for the study of material flammability in oxygen-enriched atmospheres. The test system has the capability of providing either static or flowing oxygen-enriched test environments. Though the actual combustion containing hardware is similar to other systems presently used to study the combustion of metallic materials, the new system offers excellent instrumentation capabilities presently unavailable in NASA and other industrial test systems. A description of the test system is presented and research programs underway discussed.
Ignition and Combustion of Titanium and Titanium Alloys
Authors: Gunaji MV , Sircar S , Beeson HD
Published: March 2009

Titanium and its alloys are widely used in aerospace industry where the metal's low density, high-specific strength, and corrosion resistance properties are required. Examples where titanium and its alloys are used is in turbine engines and airframes, and in oxidizing sulfuric acid environments present in sulfide pressure-leaching operations (pressure oxidation autoclaves). Titanium has been considered for use in oxygen-enriched environments such as space suit applications. However, like most metals and alloys, titanium will burn in oxygen-enriched environments. This paper describes the ignition and combustion of titanium and its alloys. The ignition propensity of titanium was determined by frictional ignition testing and the combustibility determined by promoted combustion testing. Results indicate that the Pv products required for ignition by friction are 0.0035×108 W/m2 (0.01×106 psi ft/min) and in 100 percent oxygen titanium is combustible at pressures as low as 13.8 kPa (2 psia).
Flammability of Metals in Fluorine and Nitrogen Trifluoride
Authors: Gugliemini CJ , Kadri SH , Martrich RL , Slusser JW , Vora J , Werley BL , Woytek AJ
Published: March 2009

Fluorine and many of its compounds are more aggressive oxidizers than oxygen. Flammability test results for metals in fluorine and nitrogen trifluoride patterned after Air Products' tests of metals in oxygen are reported. Although, combustion in fluorine is distinctly different than combustion in oxygen, several of the thermodynamic properties and parameters used to understand metal flammability in oxygen in ASTM G 94 are presented for the fluorine-chemicals case. They suggest substantially different metal rank orders and combustion behaviors should be found for combustion in fluorine-containing oxidants. The data appear to support this prediction.

Despite the strong oxidizing nature of fluorine, nitrogen dilution levels at various pressures were identified at which test specimens did not propagate combustion in the configuration studied. Carbon steel rods 0.25-in (0.64-cm) diameter burned in atmospheric pressure fluorine but did not propagate upwards in fluorine/nitrogen mixtures of (%F2): 35% at 115 psig (0.89 MPa), 30% at 565 psig (4.00 MPa), 25% at 1065 psig (7.44 MPa) or 20% at 2015 psia (14.00 MPa).

The nitrogen trifluoride molecule contains atomic nitrogen equivalent to a 25% nitrogen/fluorine mixture, but it absorbs energy upon dissociation. Ignition of 0.25-in. (0.64-cm.) diameter rods at various pressures was attempted for the metals: 304L and 316 stainless steel, nickel alloys C22 and C276, Nickel 200, copper, nickel alloys 600 and 625, Monel®2 400, Chrome-Moly 4130X, and aluminum. Interestingly, aluminum, as well as nickel 200, Monel® 400, and copper, appeared to have the highest thresholds, above 750–1250 psig (5.3–8.72 MPa), and 304L and 4130X each experienced sustained combustion at atmospheric pressure. Stainless steel 316 appears to have a threshold at or below 225 psig (1.65 MPa). Nickel alloys 600, 625, C276 and C22 burned at 1000 psig (7 MPa) but were not tested at lower pressures.
An Evaluation of Polymers as Ignition Sources During Particle Impact in Oxygen
Authors: Dees J , Forsyth E , Gunaji MV , Stoltzfus JM
Published: March 2009

When contaminant particles are present in oxygen systems they can be entrained in the flowing oxygen and collide with system components causing ignition and burning. This particle impact ignition mechanism has been the cause of many fires in oxygen systems and has been systematically studied in the laboratory. For the laboratory studies, materials for particles and targets are generally classified into three groups: metals, oxides (inert), and polymers. Of the three groups, metallic particles and targets have been tested most frequently. Oxide (inert) particles and targets have been studied occasionally. Polymers, however, have not been systematically studied either as particles or as targets.

In this work, four polymer materials commonly used in oxygen systems, Teflon (PTFE), Vespel SP-21, Kel-F 81, and Viton A, were evaluated as particles which were impacted against 316 stainless steel targets. Small particles, with major dimensions of approximately 250 micrometers (μm), were tested in quantities of one and five at subsonic and supersonic velocities. Single larger particles, with major dimensions of approximately 1000 and 2000 micrometers, were tested at subsonic and supersonic velocities. The oxygen pressure was maintained at 27.6 MPa (4000 psia) and the temperature was varied between 21 and 93 ‡C (20 and 200 ‡F). No ignitions of the target material occurred in any of the test series, which indicates that at least for these polymer materials and test sample configurations, particle impact ignition is unlikely. The limitations and applications of these tests results to actual oxygen systems is discussed.
Laser-Assisted Cleaning of Contaminated Surfaces
Authors: Engelsberg AC
Published: March 2009

Cleaning a surface exposed to harsh or sensitive environments during manufacture or in the field constitutes an interesting challenge. The need arises in industries ranging from microelectronics (equipment), aerospace (space vehicles and aircraft), nuclear (utilities and weapons), and chemicals. In all these industries, maintainability and reliability are of critical importance.
Clay-Oil Flocculation and its Role in Natural Cleansing in Prince William Sound Following the Exxon Valdez Oil Spill
Authors: Bragg JR , Yang SH
Published: March 2009

Natural interactions of fine mineral particles with residue oil and seawater, in a process called clay-oil flocculation, were found to create solids-stabilized oil-in-water emulsions on shoreline sediments at numerous locations in Prince William Sound following the Exxon Valdez spill. In laboratory tests using oiled sediment samples from Prince William Sound, these emulsions were shown to facilitate natural cleansing and dispersion of oil from sediments by moving water.

Microscopic examination showed that the emulsions consisted of complex and varied floe aggregates of about 1–100 microns in diameter. Fluorescence under ultraviolet light revealed that the interior of these particles consisted of numerous spheres of oil surrounded by mineral fines and seawater. X-ray diffraction and scanning electron microscope studies showed the minerals to consist of clays, quartz, and feldspar-typical components of glacial flour. Chemical analyses of the oil revealed a correlation between the fraction of polar hydrocarbons present and the amount of mineral fines bound with the oil. These factors were also related to the ease by which the oil could be removed from substrate sediments by hydrodynamic forces.

To investigate the effect of flocculation on natural cleansing, studies were conducted to determine the hydrodynamic energy needed for seawater to remove flocculated oil residues from sediments sampled from shorelines. Water was pumped at different velocities through a column packed with oiled sediment, and the amount and composition of oil removed from the sediment were measured as functions of water velocity and sediment movement. In separate tests, oil removal was observed in a wave tank that generated wave heights less than and greater than needed to move sediments. These tests demonstrated that, with clay-oil flocculation, substantial amounts of the oil could be removed at wave energies less than those needed to cause sediment movement and abrasion, which helps to explain observed removal of oil from the subsurface and from low energy shorelines where waves were not large enough to move sediments. Further, the large hydraulic cross section and nearly neutral buoyancy of floc particles removed from the sediment help to explain their efficient dispersal. The flocculation process also significantly increases the oil-water interfacial area, enhancing access to the oil by bacteria for biodegradation.

Clay-oil flocculation was found to be a beneficial process that we believe accelerated the removal of oil from shoreline sediments following the Exxon Valdez spill. The physical properties of the floc should have facilitated dispersion of the oil over large distances, thus helping to reduce buildup of hydrocarbons in subtidal sediments. Clay-oil flocculation, therefore, is another natural cleansing process that must be considered when studying the fate of oil spilled on shorelines.
Evaluation of the Toxic Properties of Naturally Weathered EXXON VALDEZ Crude Oil to Surrogate Wildlife Species
Authors: Stubblefield WA , Hancock GA , Ford WH , Prince HH , Ringer RK
Published: March 2009

The toxic properties of naturally weathered Exxon Valdez crude oil (WEVC) to avian and mammalian wildlife species were evaluated using the surrogate species, mallard duck, Anas platyrhynchos, and European ferret, Mustela putorius. This study was conducted to evaluate the potential for toxic (rather than physical) injury to wildlife species that may have been exposed to WEVC, either through external contact or through dietary uptake. Previous studies have assessed the toxicity of unweathered crude oils, including Alaskan North Slope Crude, but little information exists regarding the toxicity of a naturally weathered crude oil, typical of that encountered following a spill.

A battery of laboratory toxicity tests was conducted, in compliance with standard and published test procedures, to evaluate acute and subchronic toxicity of WEVC. These included tests of food avoidance, reproductive effects, and direct eggshell application toxicity. Naturally weathered EVC, recovered postspill from Prince William Sound, was used as the test material. No treatment-related mortalities or gross signs of toxicity were noted in ducks at oral doses of 5 000 mg/kg body weight or at dietary concentrations up to 100 000 ppm (mg WEVC/kg diet), or in ferrets at oral doses up to 5 000 mg/kg body weight. Test animals did not avoid oil-contaminated food. No significant adverse effects were noted in birds fed diets containing up to 2 000 mg WEVC/kg diet in the reproductive toxicity test. However, significant reductions in mean eggshell thickness and strength were observed in birds fed 20 000 mg WEVC/kg diets. Applications of up to 92 mg/egg of WEVC to developing eggs produced no toxic effects.

Feeding weathered EVC to ducks and ferrets at oral doses or dietary concentrations exceeding those representing maximum likely field exposures from heavily affected spill areas did not significantly affect survival, growth, or reproduction. These results suggest that naturally weathered EVC posed little toxic risk to wildlife consuming oil or oiled food items following the Exxon Valdez spill, particularly considering the environmental exposure conditions that existed in the spill-affected area after 1989.
Surveys of Murre Colony Attendance in the Northern Gulf of Alaska Following the Exxon Valdez Oil Spill
Authors: Erikson DE
Published: March 2009

Field surveys were conducted in July and August 1991 on 32 of the 36 murre (Uria spp.) colonies in the northern Gulf of Alaska to assess colony attendance (number of birds present at a colony) two years after the Exxon Valdez oil spill. The surveys focused on murre colonies because murres represented 74% of the recovered seabird carcasses and because it had been claimed that there was large-scale mortality of murres, leading to 60% to 70% decreases at some large colonies and population recovery periods of 20 to 70 years.

Murres were present at all 32 colonies, and colony attendance estimates were generally similar to those from historical (prespill) surveys, particularly for those colonies in the direct path of the spill, i.e., the Barren Islands and Chiswell Islands. Colony attendance levels in 1991 do not support the contention that murre colony attendance in the study area was drastically lower than historical levels. When colonies were grouped according to risk of oil exposure, the mean changes in attendance between 1991 and historical murre surveys did not differ significantly among the groups. Factors that could account for the observed similarity of 1991 and historical murre counts despite the high estimated mortality are (1) overestimation of mortality or (2) replacement of lost breeders through either recruitment of formerly nonbreeding individuals into the breeding population at spill-affected colonies or immigration of murres from nonaffected colonies. The findings of this study suggest that impacts of the Exxon Valdez oil spill on murre colony attendance in the northern Gulf of Alaska were relatively short-term.
Pre-fertilization zona pellucida hardening by different cross-linkers affects IVF in pigs and cattle and improves embryo production in pigs
Authors: Canovas Sebastian , Romar Raquel , Grullon Luis Alberto , Aviles Manuel , Coy Pilar
Published: March 2009

Zona pellucida (ZP) hardening (resistance to proteolysis) has been classically identified as a post-fertilization event that contributes to the block to polyspermy. Di-(N-succinimidyl)-3,3′-dithiodipropionate (DSP), a permeable amine-reactive cross-linker, was recently shown to induce pre-fertilization ZP hardening and to improve porcine IVF productivity. The objectives of this study were to investigate i) how DSP affects pre-fertilization ZP hardening and IVF in cattle, ii) if a non-permeable amine-reactive cross-linker such as bis(sulfosuccinimidyl) suberate (BS3) affects ZP hardening and IVF in cattle and pigs, and iii) whether DSP or BS3, if improvement in IVF productivity was demonstrated in either species, affectsin vitroembryo development. Bovine and porcinein vitromatured oocytes were incubated with the cross-linkers (0.06, 0.3, and 0.6 mg/ml) for 30 min. Then they were subjected to ZP digestion or IVF. In cattle, both DSP and BS3 induced ZP hardening and decreased the penetration rate, although monospermy, penetration, or male pronuclear formation was not affected. In pigs, BS3 treatment induced ZP hardening, decreased penetration and male pronuclear formation, and increased monospermy. IVF productivity only improved when porcine oocytes were exposed to DSP. When porcine zygotes derived from this treatment were further culturedin vitro, the cleavage and blastocyst formation rates increased. These results support the idea that mechanisms involved in the prevention of polyspermic fertilization in cattle and pigs have different efficiencies, and ZP hardening induced by DSP cross-linker may be useful for improving porcine embryo production.
Developmental programming: prenatal androgen excess disrupts ovarian steroid receptor balance
Authors: Ortega Hugo H , Salvetti Natalia R , Padmanabhan Vasantha
Published: March 2009

Steroid hormones play an important role in reproduction and the receptors through which they signal change in a developmental time, follicle stage, and cell-specific manner. Disruption in steroid receptor expression affects follicle formation and differentiation. In this study, using prenatal testosterone (T) and dihydrotestosterone (DHT)-treated female sheep as model systems, we tested the hypothesis that prenatal androgen excess disrupts the developmental ontogeny of ovarian steroid receptor protein expression. Pregnant Suffolk ewes were injected twice weekly with T propionate or DHT propionate (a non-aromatizable androgen) in cottonseed oil from days 30 to 90 of gestation. Changes in ovarian estrogen receptors (ER; ESR1, ESR2), androgen receptor (AR) and progesterone receptor (PGR) proteins were determined at fetal (days 90 and 140), postpubertal (10 months), and adult (21 months; only prenatal T-treated sheep studied) ages by immunohistochemistry. Prenatal T and DHT treatment induced selective increase in AR but not ER or PGR expression in the stroma and granulosa cells of fetal days 90 and 140 ovaries. An increase in ESR1 and decrease in ESR2 immunostaining coupled with increased AR expression were evident in granulosa cells of antral follicles of 10- and 21-month-old prenatal T but not DHT-treated females (analyzed only at 10 months). These findings provide evidence that an early increase in ovarian AR is the first step in the altered ovarian developmental trajectory of prenatal T-treated females, and manifestations of postnatal ovarian dysfunction are likely facilitated via altered equilibrium of antral follicular granulosa cell ER/AR protein expression.
The engineering properties of Victorian structural wrought iron
Authors: Moy S. S. J. , Clarke H. W. J. , Bright S. R.
Published: March 2009

This paper presents results, which are of general interest and relevance to the structural engineering community, from a comprehensive investigation of the mechanical properties of the wrought iron from a bridge in mid-Wales, together with data from tests over the last 125 years on wrought iron from various locations. The paper discusses the variability of wrought iron in terms of material from a single source and from different sources throughout the UK. It is shown that wrought iron is a very variable material and that assessment of wrought-iron structures needs to take account of that variability and the condition of the wrought iron. The results reported were obtained as part of a research project into the strengthening of wrought-iron structures using carbon-fibre-reinforced polymer composites.
Development of model parameters for early-age properties and crack-width prediction of slag concretes
Authors: Aly T. , Sanjayan J.G.
Published: March 2009

A study to develop the parameters of the models for predicting the deformation characteristics of normal-strength concrete incorporating slag-blended cements at early age is presented in this paper. By comparing with the previous experimental results, it was found that the basic shrinkage and creep factor decreased significantly owing to the expansion of slag concrete during the first week of moist curing. When utilising the developed models for estimating the crack width, it was found that the initial crack width of concrete subjected to restraint drying shrinkage is reduced if the slag content level increased up to 50 and 65% in the concrete mixture. Further, slag concrete tends to have less crack width and lower number of cracks in the long term compared with that with no slag.
ITZ's structural evolution during hydration in model concrete
Authors: Stroeven P. , Hu J.
Published: March 2009

The interfacial zone (ITZ) around aggregate in concrete is a crucial element in mechanical and in transport systems. Computer simulation of cement is used to approach this phenomenon. For particle-packing in the fresh state, the Software Package for the Assessment of Compositional Evolution (SPACE) system relies on a dynamic generation algorithm, reflecting production conditions. The evident effects of spatial position of hydrating particles and hydration products on structure formation of cement call for use of stereological methods. Morphological and structural evolution of the ITZ from the fresh into the hardened state is quantified by composite as well as configuration parameters. The results reveal that in the fresh state of particle packing, the ‘wall effect' reflects the decline in cement particle density in the vicinity of the aggregates, leading to a more porous ITZ, the extent of which depends on technological parameters (water-to-cement (w/c) ratio, cement fineness), but also on the type of parameters characterising material structure. As hydration proceeds, only moderately higher porosities are observed within the ITZ than in the bulk paste. The disproportional high physical bond strength in the ITZ at low w/c ratio remains apparent throughout the hydration process.
An appraisal of the ACI strut efficiency factors
Authors: Sahoo D.K. , Singh B. , Bhargava P.
Published: March 2009

The strut-and-tie modelling recommendations of the American Concrete Institute (ACI) 318-08 Appendix A are widely followed for the design of disturbed regions in concrete structures. In this investigation, an experimental appraisal of the ACI 318-08-recommended efficiency factors for prismatic and bottle-shaped struts has been carried out and inconsistency in the recommendations for bottle-shaped struts highlighted. It has been demonstrated that a bottle-shaped strut is in no way inferior to a prismatic strut in terms of strength and, consequently, the efficiency factor of bottle-shaped struts needs to be revised. An error in the ACI 318-08-recommended formulation for minimum effective transverse reinforcement in reinforced bottle-shaped struts is identified and corrected.
Annual Legumes for Forage Systems in the United States Gulf Coast Region
Authors: Foster J. L. , Adesogan A. T. , Carter J. N. , Sollenberger L. E. , Blount A. R. , Myer R. O. , Phatak S. C. , Maddox M. K.
Published: March 2009

Forage‐livestock systems in the U.S. Gulf Coast are based on perennial C4 grasses. System productivity often is predicated on significant inputs of N fertilizer, but rapidly escalating fertilizer prices raise questions about the sustainability of these systems and provide impetus for legume research. There are few successful forage legumes in the region, suggesting that alternative species merit evaluation. The objective of this study was to determine the productivity and nutritive value in North Florida of adapted legumes whose primary use is not forage. Species tested included soybean [Glycine max (L.) Merr.], cowpea [Vigna unguiculata (L.) Walp.], and pigeonpea [Cajanus cajan (L.) Millsp.]. Legumes were grown in field plots during 3 yr and sampled biweekly until the recommended maturity stage for harvest as forage. At the recommended maturity stages for harvest as forage, soybean, and pigeonpea had greater (P < 0.01) herbage mass than cowpea. Leaf‐to‐stem ratio decreased with maturity and was greater for cowpea than the other legumes from 10 through 14 weeks after planting (WAP). At the recommended maturity for harvest as forage, pigeonpea, soybean, and cowpea had crude protein (CP) concentrations of 121, 176, and 188 g kg−1, respectively; neutral detergent fiber (NDF) concentrations of 695, 423, and 447 g kg−1, respectively; and in vitro true dry matter (DM) digestibility (IVTD) of 351, 729, and 689 g kg−1, respectively. Of the three legumes studied, soybean and cowpea had the greatest potential to provide forage with the highest nutritive value for livestock in North Florida, but soybean provided greater N yield.
Long‐Term Polyacrylamide Formulation Effects on Soil Erosion, Water Infiltration, and Yields of Furrow‐Irrigated Crops
Authors: Lentz Rodrick D. , Sojka Robert E.
Published: March 2009

Two formulations of water‐soluble anionic polyacrylamide (WSPAM) are used in agriculture to reduce erosion and manage infiltration in furrow irrigations, although few if any reports have compared their effectiveness. A control and two WSPAMs, a granular form and the inverse emulsion, or oil‐based liquid form, were applied to irrigation water supplied to furrows formed in a silt loam soil with 1.5% slope during each irrigation from 1993 to 1999. Stock solutions prepared from the two WSPAMs in tap water were injected into furrow inflows to attain a concentration of 10 mg L−1 only during furrow advance. During irrigations, furrow inflow and runoff rates, and runoff sediment concentrations were measured. Crop yields were measured in five of the 7 yr. Relative to controls, both WSPAM treatments reduced runoff sediment loss equally well, decreasing soil losses by 84% per irrigation, and prevented the loss of 47.8 Mg soil ha−1 over the 7‐yr period. The yearly soil loss reductions produced by WSPAMs ranged from 66 to 99%, and may reflect changes in the electrical conductivity (EC) of the irrigation water. Both WSPAM treatments increased the proportion of applied irrigation water that infiltrated into newly formed furrows, but the emulsion produced the greatest overall increase in water infiltration fraction. As a class, WSPAM treatments increased yields by 14.3% for bean (‘Viva Pink’ Phaseolus vulgaris L.) and 4.5% for silage corn (Zea mays L.), suggesting that the cost of WSPAM applications may be recoverable. While the two WSPAM formulations provide equivalent erosion protection, differences in infiltration effects, product costs, and potential environmental impacts should be considered when selecting the formulation.
Characterization of Corn Nitrogen Status with a Greenness Index under Different Availability of Sulfur
Authors: Pagani Agustín , Echeverría Hernán E. , Andrade Fernando H. , Sainz Rozas Hernán R.
Published: March 2009

Several methodologies measure leaf greenness intensity and relate it to crop N status. There is no evidence, however, of the utility of this variable to detect N deficiencies in corn (Zea mays L.) under S deficiency. The objective of this work was to evaluate the potential of two indexes based on leaf greenness intensity to detect N deficiencies in corn under different levels of S. Two experiments at Balcarce, Argentina (Bce I and Bce II), and one at 9 de Julio, Argentina (9dJ), were conducted during the 2005–2006 and 2006–2007 seasons with different levels of N and S. Weekly measurements of greenness index (GI) were performed, and whole‐plant samples were taken at four developmental stages to determine crop N and S accumulation. No N × S interaction was found in any measured variable. Nitrogen increased dry matter N and S accumulation, grain yield, and GI. Sulfur fertilization resulted in increased S accumulation in all experiments, and grain yield at Bce II and 9dJ. This nutrient also increased GI during several crop stages in all experiments. A nitrogen sufficiency index (NSI) was related to its relative yield (R2: 0.67, 0.63, 0.43, 0.67 for stages V5–V8, V9–V11, V13–V14, and V15–V18, respectively) under different S levels. On the other hand, a new index called relative greenness index (RGI), proposed for situations that could present S deficiencies, was also related to its relative yield (R2: 0.67, 0.81, 0.63, 0.82 for stages V5–V8, V9–V11, V13–V14, and V15–V18, respectively) under different S levels. The regression lines of both indexes were coincident for all sample dates. It was concluded that crop N status can be characterized under different levels of S through the NSI. Future research, however, should test these results under a wider range of S levels.
Corn Cob Characteristics in Irrigated Central Great Plains Studies
Authors: Halvorson Ardell D. , Johnson Jane M. F.
Published: March 2009

Escalating fossil fuel cost and concern over global climate change have accelerated interest in cellulosic feedstocks, such as corn (Zea mays L.) cobs, for liquid fuel production. Little information is available about this plant organ. We compiled and summarized available cob data from several recent field studies in the Central Great Plains. Data were collected from two locations in Colorado and two in Texas that had multiple N fertilizer treatments, varying tillage systems, and different growing seasons. Cob:grain yield ratio, cob:ear ratio, cob:stover ratio, and cob N and C uptake were determined for each site. Cob yield generally increased with increasing N rate. At the high N rates, cob yield ranged from 1.44 to 2.2 Mg ha−1. Cob:stover ratio ranged from 0.14 to 0.25 at high N fertilizer levels. The N concentration varied little among N levels at any location, varying more among locations and year, ranging from 2.52 to 5.19 g kg−1. Nitrogen uptake at the highest N‐levels ranged from 4.65 to 8.37 kg ha−1. The relationship between final grain yield at 155 g kg−1 water content and oven‐dried cob yield was linear (r2 = 0.75) such that cob yield increased 0.096 Mg ha−1 for each Mg ha−1 increase in grain yield. This study provides basic information on cob yield and quality for agronomists, and examples are discussed on how the data could be useful for determining the feasibility of harvesting corn cobs as a cellulosic feedstock.
In‐Furrow Inoculation and Selection for Higher Motility Enhances the Efficacy of Bradyrhizobium japonicum Nodulation
Authors: López‐García S. L. , Perticari A. , Piccinetti C. , Ventimiglia L. , Arias N. , De Battista J.J. , Althabegoiti M. J. , Mongiardini E. J. , Pérez‐Giménez J. , Quelas J. I. , Lodeiro A. R.
Published: March 2009

The issue of competition for nodulation has received much attention in studies on soybean [Glycine max (L.) Merr.] crops because native soil rhizobia often preclude nodulation of inoculated high‐quality strains. In this work, soil placement and enhanced motility of Bradyrhizobium japonicum were investigated as strategies to improve the competitiveness of soybean inoculants applied in the presence of large populations of native (or indigenous) soybean‐nodulating rhizobia. The first strategy might allow for the enhanced distribution of inoculant rhizobia in the surface soil, compared with inoculant that is directly applied to soybean seed, while the second strategy is expected to enhance root colonization. The effects of soil placement and enhanced bacterial motility on percentage nodule occupation, grain yield, and grain N contents were examined during the 2004–2005 soybean season at three locations in Argentina, comprising soils classified as entic hapludol, argillic pelludert, and typical argiudol. The experimental design was a randomized complete block design, and main effects and interactions were also analyzed with a factorial design. Strain LP 3008, previously selected for increased motility, was more effective than the commonly inoculated strain E 109. While E 109 occupied, on average, 13.2% of nodules with seed inoculation, LP 3008 occupied 28.2%. In comparison, in‐furrow inoculation yielded 24.2 and 37.2% average nodule occupancies for E 109 and LP 3008, respectively. However, these gains in nodulation efficacy lead to a modest, nonsignificant yield increase, and grain N content was unaffected.
Application of Two Vermicomposts on a Rice Crop: Effects on Soil Biological Properties and Rice Quality and Yield
Authors: Tejada M. , González J. L.
Published: March 2009

Vermicomposts have been considered as a soil additive to reduce the use of mineral fertilizers because they provide required nutrients, increase cation exchange capacity, and improve water‐holding capacity. However, the effect of each vermicompost on soil properties and crop yield depends on its chemical composition. The main objective of this work was to study the effect of incorporating two vermicomposts of different chemical nature (cow dung, CD; and green forages, GF) at rates of 3 and 6 t C ha−1, respectively, on soil biological properties (soil microbial biomass, soil respiration and soil enzymatic activities), soil humus–enzymes complexes, nutrition (N, P, and K plant contents, pigments, and leaf soluble carbohydrate concentrations), and yield parameters of rice (Oryza sativa cv. Puntal) over 3 yr on an Aquic Xerofluvent located near Seville, Spain. Vermicomposts had a positive effect on the soil biological properties and rice quality and yield parameters with respect to the no‐vermicompost‐amended soil, although at the end of the experimental period and at the high organic matter rate, the soil microbial biomass and dehydrogenase, urease, β‐glucosidase, phosphatase, and arylsulfatase activities increased more in the CD‐amended soils compared with the GF‐amended soils (20.8, 12.8, 16.9, 17.6, 15.3, and 15.1%, respectively). However, the results obtained in the soil humus‐enzymes complexes indicate that the highest values were found in the GF‐ compared with CD‐amended soils. This increase in soil biological properties produced an increase in the plant nutrition, which increased rice quality and yield. The application of CD increased the grain protein concentration (5.6%), the grain starch concentration (7.8%), the percentage of full grains (3.1%), and the rice yield (7.9%) compared with the GF‐amended soils. These results suggest that the chemical composition of the two vermicomposts influenced the soil biological properties, and therefore in the rice yield parameters. For both vermicomposts, the application of CD originated an increase in the soil biological properties and also in the rice yield parameters than did application of GF.
History of arthroscopy
Authors: Maric Dusan , Garces Gerardo , Martinez Armando , Petkovic Lazar
Published: March 2009

Arthroscopy has developed as one of the branches of former cystoscopy. During the past 200 years a few people have made invaluable contributions to development of arthroscopy (Bozzini, Takagi, Watanabe) After the World War II scientific and technological progress was so fast that arthroscopy proved to be a valuable tool in orthopedics, not only as a diagnostic, but also as a therapeutic procedure.
Antiphospholipid syndrome accompanying systemic lupus erythematosus
Authors: Mitic Gorana
Published: March 2009

The aim of the study was the assessment of the prevalence of antiphospholipid syndrome (APS) in patients with systemic lupus erythematosus (SLE). 72 patients with SLE had been investigated, 66 females and six males, aged 17 to 70 years, average 37,03. The presence of APA was determined using both ELISA assay for antiphospholipid antibodies ASSERACHROM APA by Diagnostica Stago and clotting tests for lupus anticoagulant: activated partial thromboplastin time (aPTT), tissue thromboplastin inhibition test (TTI) and dilute Russell viper venom time (dRVVT). Antiphospholipid antibodies have been found in 24 patients (33.44%), 10 of them were. with positive lupus anticoagulant tests, 6 of them were with positive ELISA test, while 8 of them had positive coagulation and immunological tests. Clinical manifestations that could be related to antiphospholipid syndrome were present in 22 patients (30.5%). The most common were thrombotic complications in 16 patients (22.25), recurrent spontaneous abortions in 7 patients (9.7%) and thrombocytopenia in 1 patient (1.39%). Presence of antiphospholipid syndrome was determined in 15 patients (20.83%). We can conclude that there is a significant correlation between presence of antiphospholipid antibodies and both thrombotic events and recurrent spontaneous abortions in SLE patients. Occurrence of thrombotic complications is in direct correlation with the level of antiphospholipid antibodies.
Treatment of pulmonary embolism and prevention of recurrence by placement of vena cava filters in prevention of deep venous thrombosis: Case report
Authors: Vucicevic-Trobok Jadranka , Bogdanov Biljana , Trifkovic Miroslava , Srdic Svetozar
Published: March 2009

Introduction In patients with pulmonary thromboembolism it is clinical to suspect the disease, establish the diagnosis and initiate anticoagulation treatment as early as possible in order to prevent relapses, which may be fatal. Deep venous thrombosis of lower extremities is the most common site of origin, which initially may remain obscure. Case report Two weeks prior to admission the patient had right-sided chest pain accompanied with dyspnea, interpreted and treated as pleuropneumonia. Pulmonary thromboembolism was suspected due to clinical symptoms, chest X-ray, elevated enzyme levels findings, blood gas analysis with hypoxemia and ECG with right heart overload. The diagnosis of pulmonary thromboembolism confirmed by lung scintigraphy presented with perfusion defects. After twenty days of heparin therapy, the patient developed left leg edema. Ultrasound screening confirmed bilateral iliac-femoral popliteal vein thrombosis of iliacofemoropopliteal veins bilaterally. Phlebography performed via jugular vein disclosed thrombotic material in the right common iliac vein, as well as in the vena cava inferior. In the course of the procedure vena cava filter has been placed. Discussion Although the patient was receiving anticoagulation heparin therapy, he developed pulmonary thromboembolism relapse and deep venous thrombosis. In our patient, vena cava filter placement was aimed at preventing pulmonary thromboembolism relapse. Since a deficit of S protein was also established, the patient is unfortunately likely to develop thrombosis at other sites as well. Conclusion In our patient pulmonary thromboembolism was a consequence of deep venous thrombosis, and the diagnosis was established by ultrasound screening of the lower extremities and confirmed by phlebography. During phlebography vena cava filter was placed in order to prevent pulmonary thromboembolism.
Annual report of the Municipal and Eye Hospital in Subotica for 1889
Authors: Sente Marko , Sente Ruza
Published: March 2009

Introduction The paper is the translation of the report of the Head physician of the Municipal Hospital in Subotica for 1889. It shows the number of patients, the number of checkups, the number of outpatients and inpatients, distribution by sex, age, place of residence, the frequency of patients by months and groups of diseases, the average length of treatment the number of cured, unsuccessfully treated and deceased patients, the most significant surgeries, the number of doctors employed and a detailed survey of groups of diseases. Annual report From January 1, to December 31, 1889 6.123 patients were treated, 5.141 outpatients and 982 inpatients; 24.644 visits, 69 patients on average, 2.884 men and 2.257 women; 662 under 1 year of age; 828 aged 1 to 5; 1.655 aged 5 to 20; 1.854 aged 20 to 80; 142 patients over 80 years of age. 4.260 patients were from Subotica and 881 from other parts of the country. 19.436 patient days were required, 19 3/4 on average. 747 patients were cured, condition improved in 132, 60 were unsuccessfully treated and 43 patients died. Cerebral and spinal cord diseases occurred in 73 outpatients and 38 patients (the same distribution outpatients + inpatients goes for all diseases, respectively); nervous system diseases 82+18; ear diseases 139+2; eye diseases 1706+220; nose diseases 12+0; respiratory tract diseases 478+95; circulatory system diseases 35+13; lymphatic system diseases 51+5; mouth and throat lumen diseases 207+9; coronary diseases and diseases of intestinal mucosa 711+18 genitourinary tract diseases 252+66; skin diseases 440+107; muscle, gland and tissue diseases 104+23; joint diseases 75+16; bone diseases 56+20; acute infectious diseases 344+43; chronic infectious disease 143+137; general nutritional disorders 222+43; poisonings 3+2; childbirths 8+6.
Treatment algorithms for high-energy traumas of lower extremities
Authors: Jovanovic Mladen , Janjic Zlata , Maric Dusan
Published: March 2009

Introduction High-energy traumas are open or closed injuries caused by force (missile, traffic injuries, crush or blust injuries, falling from heights), affecting the body surface and transferring high amount of kinetic energy inducing great damage to the tissue. Management of such lower extremity injuries has evolved over past several decades, but still remains a difficult task for every surgical team. Specific anatomic and functional characteristics combined with extensive injuries demands specific treatment protocols. Multiple injuries In a multiple injured patient the first priority is management of life-threatening trauma. Despite other injuries, surgical treatment of limb-threatening injuries must start as soon as life-threatening condition has been managed. Treatment algorithms Algorithms are especially beneficial in management of severely injured, but salvageable extremities and in making decision on amputation. Insight into mechanisms of injury, as well as systematic examination of the affected limb, should help us understand the extensiveness of trauma and make an adequate management plan. Prevention of infection and surgical approach Prevention of wound infection and surgical approach to high- energy limb trauma, which includes wound extension, wound excision, skeletal stabilization and if necessary muscle compartment release, should be done in the first 6 hours after injury. Methods of soft tissue reconstruction Commonly used methods for soft tissue defects must provide wound coverage in less than five days following injury. Rehabilitation Early passive and active mobilization and verticalization of patients is very important for successful treatment. Conclusion Good and timely evaluation of the injured and collaboration between plastic and orthopedic surgeons from the beginning of treatment, are crucial for final outcome.
Treatment of scurvy - historical background: A gross injustice done to dr. Maksim Nikolic-Miskovicev from Sr. Karlovci in the 19th century
Authors: Maksimovic Jovan
Published: March 2009

This paper reviews historical aspects regarding medical knowledge on scurvy vitamin C deficiency, and its etiological factors. This disease used to affect naval-crews on long lasting sea voyages, soldiers during times of war and the poor. Although efficient therapy of scurvy (fresh vegetables, lemon juice) was known in the mid-18th century, its etiology was not known. It was believed to be caused by the cold, moist winds, unhealthy evaporations malnutrition and it was called "alkaline disease". It was established that acid substances like lemon juice, had beneficial effects on the disease However, it was soon generally accepted that it was caused by deficient diet. In 1830, Dr. John Elliotson, Professor of Medicine at London University supported this opinion. In 1928, Albert Szent Gyordyi, professor of Chemistry and Biochemistry at Szeged and Budapest Universities, isolated vitamin C from green pepper, vegetable proved to be rich with vitamin C. Due to this discovery, and some discoveries regarding biological processes, he was awarded the Nobel Prize for medicine and physiology in 1937 Back in 1864, a military doctor in Belgrade, Dr. Maksim Nikolic-Miskovicev from Sremski Karlovci, wrote to Ministry of Defence of the Serbian Principality. He informed the authorities about a successful, quick and cheap cure for scurvy - pepper juice. A medical board headed by Dr. Vladan Djordjevic was formed to evaluate his discovery. Dr. Nikolic-Miskovicev was underestimated and laughed at, and his discovery was completely forgotten The aim of this paper was to correct injustice done to Dr. Maksim Nikolic-Miskovicev.
New aspects of normolipidemic dyslipoproteinemias
Authors: Djeric Mirjana
Published: March 2009

Introduction Normolipidemic dislipoproteinemias include various disorders of different lipoproteins, of their subfractions or some apolipoproteins, of primary or secondary origin, which are widespread among general population and, like hyperlipoproteinemias, they are associated with the risk for premature atherosclerosis. Decreased level of HDL cholesterol It is a primary, familial hypoalphalipoproteinemia, which is commonly associated with obesity, diet rich in carbohydrates, decreased physical activity and excessive use of coffee and some drugs. Hyperapobetalipoproteinemia It is characterized by increase of apo B-100 in LDL particles, most probably as a consequence of increased hepatic synthesis. Apolipoprotein E isoforms ApoE4 isoform is associated with elevated LDL-cholesterol concentration due to rapid IDL to LDL conversion. Electrophoretic disorders The most important is the latent type IV (pre-beta) or IVb (pre-beta1) with decreased VLDL clearance. Prolonged postprandial lipemia It is common in obesity, NIDDM and coronary heart disease, as an independent risk factor for premature atherosclerosis. Increased oxidative modification of the LDL and HDL particles Oxidatively modified LDL may have a key role in the pathogenesis of atherosclerosis and oxidative modification of HDL reduces its transport capacity and its inhibition of LDL oxidation. Increased level of Lp(a) Lp(a) is an independent risk factor for premature atherosclerosis, primarily in young and middle-aged men, in persons with elevated global cardiovascular risk factor profile, decreased HDL-cholesterol, and hypertension. The risk is smaller in persons taking hypocholesterolemic drugs. Also, it is elevated in NIDDM, hypothyroidism and kidney disease.
Root canal preparation techniques using nickel-titanium rotary instruments
Authors: Brkanic Tatjana , Zivkovic Slavoljub , Drobac Milan
Published: March 2009

Introduction The main purpose of endodontic treatment is to clean the root canal system, eliminate the infected and toxic contents, and shape it in order to get a tridimensional obturation. The aim of this paper is to inform dental practitioners about crown-down techniques for root canal preparation using nickel-titanium rotary instruments. Root canal preparation Today most endodontists believe that root canal preparation is more officious, cleaning and shaping are better, if pre-enlargement of coronal two thirds is performed first, and shaping of the apical part later. Machine driven rotary instruments provide much quicker and better root canal preparation. Conclusion Contemporary endodontic rotary files vary in regard to their taper, cutting blades, guiding tip and material they are made of. The usage of rotary nickel-titanium files adds a new quality to root canal preparation.