bluuebunny/crossref_metadata_2025_split huggingface dataset:
Loess and dust on Earth and Mars: particle generation by impact mechanisms
Authors: O’Hara-Dhand Ken , Taylor Richard , Smalley Ian , Krinsley David , Vita-Finzi Claudio 
Published: March 2010

Abstract
Impact between windblown quartz grains as a source of desert dust is consistent with laboratory abrasion experiments and has received some field confirmation in the Negev. The suggestion is that an important process on Mars now gains support from laboratory studies; even though their geochemical interpretation is controversial, they show that dust generation by impact is tenable even for quartz.
A simple mechanism for small dust production from sand seas is proposed; internal stresses can be mobilized by impact energy. A speculative mechanism (the andesite scenario) is proposed for fine particle production by particle impact on Mars. The internal stress range in terrestrial sand grains may vary, depending on the nature of the source rock, and this may influence particle production by impact processes.
Luminescence of aqueous reactions derived NiWO4 powders and sol-gel deposited films
Authors: He Haiyan 
Published: March 2010

Abstract
NiWO4 powders have been synthesized by reaction between NiCl2 and Na2WO4 aqueous solutions and following calcinations at different temperatures. X-ray diffraction and scanning electron microscopy analysis were used to characterize the powders. Single phase NiWO4 powders were formed above a calcining temperature of 600 °C. X-ray diffraction analysis indicated that the NiWO4 powders had a monoclinic structure and particle size of 26.8 nm and 30.3 nm for calcining temperatures of 600 °C and 700 °C, respectively. A little increase in intensity of the X-ray diffraction peaks was observed when increasing the calcining temperature from 600 °C to 700 °C. Scanning electron microscopy indicated that powders had uniform and very small particle size. The powders showed a broad blue-green emission band. The broad band of NiWO4 powders calcined at 600 °C consisted of 423.2 nm (2.93 eV), 487.3 nm (2.54 eV) and two weak bands at 447.0 nm (2.77 eV), and 532.0 nm (2.33 eV). Small shifts in the peaks of excitation and luminescence and small increases in intensities were observed when increasing calcining temperature to 700 °C. The films were deposited using the sol-gel method and using the precipitate as starting materials. The deposited films showed a similar blue-green emission to that of the powders.
High temperature stability of Cr-carbides in an experimental Co–Re-based alloy
Authors: Mukherji Debashis , Klauke Michael , Strunz Pavel , Zizak Ivo , Schumacher Gerhard , Wiedenmann Albrecht , Rösler Joachim 
Published: March 2010

Abstract
The stability of the microstructure at high temperatures was studied in an experimental Co–Re-based alloy. The experimental alloy is mainly strengthened by Cr-carbides, particularly by those in the form of thin lamellar plates. Electron microscopic investigation on samples exposed for up to 1 000 h to temperatures of 1 000 and 1 200 °C showed that Cr23C6 type carbides present in the alloy in different morphologies are unstable at these temperatures. It was also observed that the alloy hardness dropped after exposing the samples to elevated temperatures and much of this loss occurred within the first 100 h. In-situ diffraction measurements with synchrotron radiation showed that carbide dissolution started as early as 3 h of holding at 1 000 °C. Moreover, in-situ small angle neutron scattering results indicated that the carbides at the grain boundaries and the blocky carbides dissolve first and then the thin lamellar carbides. Further, the enrichment of Cr in the Co-matrix phase, which took place due to the dissolution of Cr-carbides, stabilized a Cr–Re-rich σ phase. Although the dissolution of lamellar carbides results in a significant loss of strength, the formation of σ phase with extremely high hardness partly compensated the for loss. The σ phase is stable even at 1 200 °C.
Phase transformation temperatures of pure iron and low alloyed steels in the low temperature region using DTA
Authors: Smetana Bedrřich , Zlá Simona , Dobrovská Jana , Kozelský Petr 
Published: March 2010

Abstract
The paper reports a study of temperatures of phase transitions of nine samples of real grades of low-alloyed steels, including one sample of pure iron, using differential thermal analysis. Temperatures of phase transitions were measured in the low-temperature interval (20 – 1 000 °C). Investigated systems were analysed at selected rates of heating/cooling and then temperatures of phase transitions for zero heating/cooling rate were determined. The results obtained are compared with temperatures of the equilibrium metastable diagram Fe – C, with results from the software IDS and with temperatures of phase transitions calculated according to relations published in available literature. It follows from the results that differences, sometimes considerable ones, still exist between experimental and theoretical data, which implies the necessity for further systematic research in this area.
Effect of ECAE conditions on the microstructure, texture and mechanical properties of an extruded Mg–Zn–Y–Zr alloy
Authors: Tang W. N. , Chen R. S. , Zhou J. , Han E. H. 
Published: March 2010

Abstract
Equal channel angular extrusion (ECAE) experiments of an extruded Mg–Zn–Y–Zr alloy with an intense basal texture were performed up to 8 passes at 250 and 350 °C through route Bc (billets with a rotation of 90° in the same direction between passes) and route A (without rotation between passes). It was found that under these ECAE conditions significant grain refinement was achieved. The initial texture of the alloy gradually altered as the number of ECAE passes increased. The ductility of the alloy was improved in all the cases after eight passes. The yield strength of the alloy ECAEed through route Bc considerably decreased with the passes increasing, as a result of the formation of the texture component with the basal planes inclined at about 45° to the ECAE direction. The yield strength of the material ECAEed at 250 °C with a finer grain structure was considerably lower than that at 350 °C with a coarser grain structure. This abnormal phenomenon was attributed to more crystals in the former being oriented to be more favorable for basal slip.
The study of recrystallisation and crystallographic texture genesis in industrial steels
Authors: Réglé Hélène 
Published: March 2010

Abstract
Charles Crussard actively participated in the foundation of the IRSID laboratory in 1948. He integrated this institute in 1952 as chief of the Physical Metallurgy Department and among the scientific fields that he initiated were the plasticity and the recrystallisation of steels. Nowadays, these are still active research fields at the ArcelorMittal Research laboratory (formerly called IRSID) and the purpose of this paper is to illustrate the heritage of the research subjects that Crussard initiated and how his vision has influenced our work at IRSID.
High-speed milling strategies in mould manufacturing
Authors: Aksoy Ziya , Gür Yílmaz , Eren İlker 
Published: March 2010

Abstract
High-speed cutting is one of the key issues in mould manufacturing. But to apply high-speed milling to mould manufacturing, unlike conventional milling, it is necessary to define specific cutting parameters. This article aims to define the influence of milling strategies and cutting parameters, such as cutting speed, feeding speed, cutting tool tilting angle, on the process stability.
Long tool life and cutting strategy have a major influence on the results of machining hardened steel. Machining with drawing cut and down-cutting in copper and with drawing cut and up-cutting in hardened steel gave the best results with respect to tool wear and surface quality. Tool approach across the feeding direction results in heavy impact loads on the tool which lead to heavy tool wear and substantial dimensional deviations.
Good surface quality is achieved in machining of a work piece of 2 363 steel (X100CrMoV51) hardened to 60 HRC, using the strategy of up-cutting with drawing cut and a tool approach with a tilting angle of 15 degrees. While up-cutting allows for achieving better surface quality, down-cutting provides longer tool life than up-cutting for all angles of approach.
DISTRIBUTION OF n‐PARAFFINS IN MARINE ORGANISMS AND SEDIMENT1
Authors: Clark, Jr. R. C. , Blumer M. 
Published: March 2010

Twelve species of benthic algae from the northeast coast of the United States, three species of planktonic algae grown in the laboratory, a pelagic alga, a sample of mixed phytoplankton and zooplankton, and a recent marine sediment were analyzed for their normal paraffin distribution from C14H30 to C32H66.Normal paraffins occurred in all samples. Benthic and planktonic algae and the mixed plankton sample exhibited only a slight odd‐carbon predominance. All algae showed a major maximum at n‐C15H32 or n‐C17H36, a minimum between n‐C18H38 and n‐C31H44 and a secondary maximum between n‐C27H56 and n‐C30H62. In all these features, the algae and the plankton differed from recent marine sediments. This suggests that the normal paraffins of recent marine sediments are largely derived from sources other than the organisms studied.Differences in the hydrocarbon distribution patterns of various classes of benthic algae may be of taxonomic value. Pristane occurs in several benthic and planktonic algae; phytane, if present, occurs at a concentration too low to be detected by the method used.
THE COPEPODA AND CLADOCERA OF A MISSOURI RIVER RESERVOIR: A COMPARISON OF SAMPLING IN THE RESERVOIR AND THE DISCHARGE
Authors: Cowell Bruce C. 
Published: March 2010

An automatic plankton sampler was installed in the powerhouse of Gavins Point Dam to monitor plankton in discharges from Lewis and Clark Lake. These data and samples from the reservoir taken with tow nets indicated that the automatic sampler can be used exclusively to monitor changes in species compositions and densities of Copepoda and Cladocera.The annual discharge of Copepoda and Cladocera from Lewis and Clark Lake was estimated to be 12,619 metric tons, wet weight. Discharges of zooplankton from Lake Francis Case (Ft. Randall Reservoir), 80 km upstream, appear to have considerably more influence upon standing crops in Lewis and Clark Lake than the water exchange rates or the inflow from tributary creeks.
COPROPHAGY IN MARINE ANIMALS1
Authors: Frankenberg Dirk , Smith K. L. 
Published: March 2010

Rates of coprophagy were determined in 38 feeding studies. The animals consumed from 0 to 83% of their body weight in fecal pellets during 48 hr. The fecal pellets used included those of the polychaete Onuphis microcephala, a prosobranch gastropod (family Ilydrobiidae), the pelecypod Crassostrea virginica, the crustaceans Callianassa major and Penaeus setiferus, and the telcost Mugil cephalus. The animals offered these pellets included three polychaetes, four gastropods, three pelecypods, seven crustaceans, and three telcosts.Coprophagy rates are compared with calculated maintenance food requirements of the test animals. Fecal ingestion rates were positively correlated with carbon and nitrogen contents of the pellets. The potential effects of coprophagy in marine ecosystems arc discussed emphasizing the effect of coprophagy on the overall energy transfer efficiency of marine food chains.
ENHANCED PHOTOSYNTHETIC ASSIMILATION RATIOS IN ANTARCTIC POLAR FRONT (CONVERGENCE) DIATOMS1
Authors: Mandelli Enrique F. 
Published: March 2010

Diatom populations from the Antarctic Polar Front (convergence) in the Drake Passage area exhibited relatively high : chlorophyll a ratios at light saturation.The permanent water column instability and the adverse meteorological conditions observed in the central Drake Passage area seem to produce a light‐color stress on the physiology of convergence diatoms that are restricted to a blue‐green light environment during their life cycle.The enhanced photosynthesis: chlorophyll a ratios that were determined in experiments with Antarctic Polar Front diatoms when exposed to white (fluorescent) light sources, may be related to the short‐wavelength light background of these diatoms.
ATTACHED EPIFAUNA—SUBSTRATE RELATIONS
Authors: Driscoll Egbert G. 
Published: March 2010

Examination of nine attached or sedentary epifaunal species in Buzzards Bay, Massachusetts, shows an anomalous distribution for Cliona celata. The other species are Microciona prolifera, Astrangia danae, Chaetopleura apiculata, Anadara transversa, Anomia simplex, Crepidula fornicata, C. plana, and C. convexa. With the exception of C. apiculata, all are suspension feeders. All forms except Crepidula are more abundant on bottoms with a low silt‐clay content and a mean grain diameter in the medium sand range. They are more plentiful in sediments coarser than those in which infaunal suspension feeders reach their maximum abundance. It is suggested that the stronger currents associated with coarser sediments provide an increased food supply that results in their more plentiful occurrence.All species, except the boring sulfur sponge C. celata, are found abundantly only on bottoms rich in dead shell material. The occurrence of C. celata is anomalous because, although it requires calcareous surfaces for initial fixation, the adult γ‐stage is more plentiful on bottoms poor in dead shells than elsewhere. It is suggested that C. celata reduces the abundance of dead shells through its boring activities, leading to a depletion of other species that require hard surfaces for fixation.
THE SEASONAL AND VERTICAL DISTRIBUTION OF SUSPENDED PARTICULATE MATTER IN AN AREA OF THE NORTHEAST PACIFIC OCEAN1
Authors: Hobson Louis A. 
Published: March 2010

Concentrations of the particulate matter, particulate organic carbon, and particulate carbohydrate were determined in an area of the northeast Pacific Ocean, at depths between the surface and 4,000 mn, on six occasions in two years. Below 250 m, concentrations of particulate matter ranged from 30 to 1,000 mg/m3, particulate organic carbon from 8 to 110 mg/m3, and particulate carbohydrate from undetectable to 30 mg/m3. There was more particulate matter in winter than in spring and summer. This temporal variation appeared to be related to variations in advection.The particles making up about 90% of the mass of the particulate matter with diameters greater than about 2 µ ranged between 8‐ and 44‐µ diameter. Sinking rates were calculated (0.1 to 10 m/day) and were slow compared with horizontal speeds. Thus, the influence of phytoplankton production in the area of the concentration of particles below 250 m in that area was of minor importance.Below 250 m, the ratios of the variables and particle size showed no consistent changes with depth, suggesting that the particles were not rapidly oxidized while suspended in the water column.
DISTRIBUTION AND ECOLOGY OF LANCELETS (ORDER AMPHIOXI) OVER THE CONTINENTAL SHELF OF THE SOUTHEASTERN UNITED STATES
Authors: Cory Robert L. 
Published: March 2010

The lancelet Branchiostoma caribaeum Sundevall has been reported infrequently from the southeastern Atlantic Coast of the United States; no study had been made of its abundance, distribution, or ecology on the continental shelf. Lancelets were collected with a sand dredge and Campbell grab from North Carolina to Florida.Concentrations of lancelets were found south of Cape Hatteras. There is a 2 to 18 km wide belt that is rich in lancelets extending from Charleston, South Carolina, to at least Cape Kennedy, Florida. The largest numbers are off South Carolina and Georgia, where population densities reach 200/m2 (Campbell grab) or 57/liter (sand dredge). Most specimens were taken from coarse, shelly, siliceous sand. A few were occasionally collected from finer sands, but none from silt. Most were taken from depths between 10 and 30 m.
THE SECCHI DISC
Authors: Tyler John E. 
Published: March 2010

The theory and practice of the Secchi disc experiment are discussed. It is shown, in theory, that the Secchi disc reading can be used to calculate the sum of the total and diffuse attenuation coefficients, α and K. To obtain independent values of α and K it is necessary to make some other measurement.Some recent measurements of the per cent of surface light reaching various depths, obtained in conjunction with Secchi disc readings, are discussed with respect to their usefulness in determining α and K independently.It is suggested that the Secchi disc could be calibrated against modern instrumental measurements of α and K and a practical value for apparent contrast thus determined for the Secchi disc experiment. However if modern instruments are available for measuring α and K, it would probably be better not to undertake such a calibration.
RESPIRATORY RATES OF MIGRATING ZOOPLANKTON IN THE NATURAL HABITAT
Authors: Bishop John W. 
Published: March 2010

Rates of oxygen consumption by zooplankton in Cayuga Lake were measured when the lake was stratified. The effects of temperature, pressure, and light were examined.Animals from the epilimnion, mostly cladocerans, and from the hypolimnion, mostly copepods, respired at similar rates in their respective habitats. When the animals were placed in the same habitats, copepods from the hypolimnion had the greater rates of respiration. Copepods, which migrated over an extensive vertical distance daily, were less sensitive to changes in depth than were cladocerans, which remained within a narrow vertical range. The copepods were less affected by changes in pressure and temperature within than outside their range of migration.
PHYTOPLANKTON‐ZOOPLANKTON RELATIONSHIPS IN NARRAGANSETT BAY. III. SEASONAL CHANGES IN ZOOPLANKTON EXCRETION RATES IN RELATION TO PHYTOPLANKTON ABUNDANCE1
Authors: Martin John H. 
Published: March 2010

Phytoplankton and zooplankton were sampled at three stations in Narragansett Bay over a nine‐month period at weekly or biweekly intervals. The freshly‐caught plankton was then utilized in laboratory experiments in which zooplankton oxygen consumption and phosphorus and nitrogen excretion were measured.Nitrogen excretion was minimal when phytoplankton was abundant and vice versa; this phenomenon may be due to the animals’ greater utilization of protein as an energy source when food is scarce. A similar relationship was observed between food abundance and phosphate excretion, and it was hypothesized that when food was abundant low rates of P excretion indicated that lipid was being stored or used in egg production or both. When food was scarce more lipid was used for energy and rates of P excretion increased.From the experimental results, it was estimated that the zooplankton provide only a small fraction of the required N and P to the phytoplankton during periods of phytoplankton abundance. However, during periods of phytoplankton scarcity, when plant nutrient requirements are low and zooplankton excretion rates are high, the zooplankton provide amounts of N and P in excess of phytoplankton demand.
THE FRESHWATER MUSSEL AS A BIOLOGICAL MONITOR OF PESTICIDE CONCENTRATIONS IN A LOTIC ENVIRONMENT1
Authors: Bedford J. W. , Roelofs E. W. , Zabik M. J. 
Published: March 2010

Two species of freshwater mussels were introduced into the Red Cedar River at six different locations and analyzed for pesticide content following different lengths of time in the river. DDT and its metabolites, TDE and DDE, were found in all mussels analyzed. The concentration of DDT and its metabolites increased significantly in a downstream direction and increased significantly with time before reaching a plateau. Methoxychlor was found in mussels introduced into the lower sections of the study area. Aldrin was found in all mussels on two dates of retrieval from the river but was not found before or after these dates.Mussels collected from the upper portion of the study area contained small concentrations of DDT and its metabolites. There was no significant difference in pesticide content between species.
BACTERIAL CAROTENOIDS FROM FRESHWATER SEDIMENTS1
Authors: Brown Seward R. 
Published: March 2010

Sediment cores from Little Round Lake, Ontario, contain a band extending from 200 to 225 cm beneath the mud‐water interface that is rich in bacterial carotenoids. Crystalline preparations of spheroidenone were obtained from extracts of the sediment, together with smaller quantities of spheroidene (pigment Y) and 2‐keto‐spirilloxanthin (P‐518). The bacterial carotenoids occur in association with algal carotenoids, chlorophyll derivatives, and bacteriopheophytin.Cis‐trans isomerization of the compounds appears to have taken place in the sediments. Three stereoisomers of spheroidenone and two of spheroidene were found. P‐518 was isolated only in the trans form. The isomerization process may have geochemical implications.No morphologically distinguishable remains of the organisms that produced the pigments could be found in the sediments. The relative proportions of the three fossil xanthophylls are in close agreement with those found in senescent cultures of Rhodopseudomonas spheroides when grown under aerobic conditions. Identification of the organism is attempted, based on comparison of pigment distribution in the Athiorhodaceae with that of the fossil pigments from the lake sediment.
THE OPTICAL CHARACTERIZATION OF NATURAL WATERS BY MEANS OF AN “EXTINCTION COEFFICIENT”1
Authors: Smith Raymond C. 
Published: March 2010

Natural waters are frequently characterized by an extinction coefficient that is generally recognized as a function of the spectral response of the photoprocess as well as of the spectral transmission of the water.The extinction coefficients for two distinct water types are calculated for three types of photoreceptors to demonstrate the manner in which the extinction coefficient depends upon the photoprocess. The visual response of the human eye and the photosynthetic response of Chlorella have been chosen as examples of biological photoprocesses: these are compared with a hypothetical receptor sensitive to the total radiant energy from 350 to 700 mµ. Extinction coefficients for the two water types have been calculated which relate specifically to: the total radiant energy within the limits 350 to 700 mµ; the visibility of objects in the water; and the photosynthetic activity of the chosen plant. Support is given for the suggestion that the extinction coefficient for the total radiant energy beween 350 and 700 mµ provides the most accurate method for characterizing the photosynthetically useful radiant energy in natural waters.
SEASONAL VARIATION IN THE SAND CRAB EMERITA ANALOGA (DECAPODA, HIPPIDAE) IN THE SANTA BARBARA AREA OF CALIFORNIA
Authors: Barnes Nora B. , Wenner Adrian M. 
Published: March 2010

Studies were made of the population structure and life cycle of the sand crab Emerita analoga (Stimpson). Frequent sampling of the beach and of the plankton during a two‐year period indicates: 1) the population structure of the species differs from beach to beach; 2) an aggregation is not necessarily characteristic of the entire beach population; 3) seasonal changes drastically alter the population structure of sand crabs; and 4) occurrence and abundance of zoeae in the plankton closely parallel the arrival of megalopae on the beaches, but not necessarily on any one beach.The life cycle of this species can now be summarized as follows: The mating season in late spring and summer precedes a continual production and release of young during the summer. These pelagic zoeae pass through at least five molts before returning to shore as megalopae. Megalopae arrive in quantity on our beaches as early as September and continue to arrive during winter and spring. By mid‐November the reproductive females that prevailed in late summer apparently disappear. The majority of the beach population during winter and early spring consists of megalopae, juveniles, and males; this suggests an annual cycle for the species.The progressive seasonal increase in the percentage of females in the larger sizes, coupled with the relative absence of females in some of the smaller size classes, suggest a sex reversal (protandric hermaphroditism).