Results Of Sedimentation Analysis Research Articles

Development of methodological approaches to assessing the technological properties of oat grain

The range of methods for assessing the quality of grain and its technological properties in cereal crops, of oat in particular, is extremely limited. The available methods are labor-intensive and not always sufficiently informative. The variety of modern processing methods dictates the necessity in searching for more universal and informative assessment methods. Cereal crop breeding also requires high-speed and low-cost methods for assessing grain quality. The present work is a methodological study that uses a limited set oat accessions from the genetic collection of VIR, differing by geographical origin and contrasting technological properties, with an aim of developing a new grain quality assessment method and testing new methods for analyzing technological properties. The resulting criteria are compared with each other and with more traditional indicators. New systems for assessing the technological properties of grain of naked and covered oat have been proposed. A new method of sedimentation analysis for cereal crops is proposed. The diversity of the oat protein complex is exemplified in the results of sedimentation analysis, and of the carbohydrate complex – in the results of its testing by a micro-visco-amylograph. The variety of interactions between oat grain storage substances and wheat material during joint processing is shown by assessing the rheological properties of the dough mixture using a farinograph. The obtained results can be recommended for the assessment for breeding purposes, as well as for obtaining complete information about the quality of oat grain for the purpose of its further processing.

Sediment Classification using Envirometric Technique: A Study Case in Pahang River, Malaysia

Sedimentation is a main river problem in Malaysia. Particle size sediments analysis the river provides useful information to evaluate the rate and pattern of erosion, transportation and deposition at a time. The sediments sizes are classified according to sand, silt and clay. This study discusses about the results of sedimentation analysis at the Pahang River from 3 until 6 June 2015. 13 sampling stations were selected. The parameters used in this study are based on grain size distribution (g). Total of different sizes of material classifications were calculated using Phi scale (o) in older to statistically calculate their mean (M), standard deviation (D) and skewness (S). In this study, envirometrics technique were used to analyzed the classify parameter of this sediments. The classify results for each parameters mean, skewness and standard deviation has dominated by three main class like coarse sand, medium sand and fine sand size. Analysis of particle size sediment (M) shows the middle, right and left bank river is dominated by fine grain size with the phi 2 to phi 3. The uniformity of sediment or standard deviation (D) on the study ISSN 1394 2506 Ata et al: KLASIFIKASI SEDIMEN MENGGUNAKAN TEKNIK ENVIROMETRIK: SATU KAJIAN KES DI SUNGAI PAHANG, MALAYSIA 1172 areas has a worst with the fine grain sand with the phi 1 to phi 2. For the skewness (S), sediment size in study areas is coarse and very coarse size with phi -0.1 to phi -0.3 and phi -0.3 to phi -1. Therefore, Pahang River areas is an easily to change as a geomorphology landscape that are easily eroded by rain and change of the discharge rate.

A Simple Approximate Formula for the Aspect Ratio of Oblate Particles

AbstractA simple approximative formula is derived, which can be used to quantify the shape of oblate particles or an average shape of the corresponding particle system, when the results of sedimentation analysis (Stokes equivalent diameters) are known and results from either microscopic image analysis (assuming stable orientation, i.e., with the plane perpendicular to the direction of observation) or laser diffraction (assuming random orientation) are available for the same sample. In the latter case Cauchy's stereological theorem is applied to account for random orientation. Furthermore, it is shown that for sufficiently large aspect ratios, this formula is very close to the well‐known Jennings‐Parslow relation and can replace this more complicated expression in many practical cases, e.g., in the routine characterization of ceramic raw materials (kaolins and oxide or non‐oxide platelet powders).

Erosion modeling of past land‐use practices in the Fiume di Sotto di Troina river valley, north‐central Sicily

AbstractThe chronology and pattern of Holocene landscape development in the Nebrodi Mountains of north‐central Sicily, seen in valley alluviation and the pedological record, has been investigated in the Fiume di Sotto di Troina valley. Intensive geomorphological survey has revealed three phases of alluvial aggradation reflecting increased hillslope disturbance during the late Pleistocene and Holocene. The results of sediment analyses, archaeological survey, and literary evidence were combined in a Geographical Information System (GIS) in order to model the potential erosion caused by different land‐use practices throughout history. This paper presents the erosion model used to investigate possible Roman land‐use practices and their effects on landscape change as documented in the catchment basin. The results of the model support a correlation between intensive pastoralism and the erosional phases documented in the sedimentary record. © 2005 Wiley Periodicals, Inc.

Determination of natural radioactivity in Euphrates river

Levels of naturally occuring radionuclides (radium isotopes, U isotopes, 210Po and 210Pb) in water, sediments and biota samples collected from Euphrates river during the 1999–2000 period have been determined. Results have shown that the water contained relatively high levels of 226Ra; the largest value of 1150 mBq·l−1 was observed. These relatively high levels of 226Ra, which is one of the main radioactive contaminants in the oil industry, may be due to past discharges of production water from the oil fields situated near the river banks. 226Ra/238U activity ratio was found to be more than unity in all water samples varying between 13 and 242. In addition, the results of sediment analyses have also shown lower values for 228Ra/226Ra activity ratio than unity in those samples collected nearby the oil fields. Moreover, concentrations of other naturally occurring radionuclides such as uranium isotopes, 210Po and 210Pb for most samples (water, sediments and biota) were found to be within the natural levels and in agreement with those values reported for other local and international studies. Only mussel species were found to contain high levels of 210Po, about 1335 Bq·kg−1 dry mass was observed in Anodonta sp species. However, the results of this study can be considered a baseline for monitoring of future changes. A regional research project (including Turkey, Syria and Iraq) to study this river (from the Anatolia Mountains to the Arabian Gulf) is necessary to determine the impact of all potential sources of contaminants.

Hagelseewli: a fascinating high mountain lake — suitable for palæoclimate studies?

Summary and conclusions The Swiss high mountain lake Hagelseewli is cur-rently being sampled within the framework of theinternational MOLAR project to investigate its suit-ability as a source of proxy climate data. Preliminaryresults from 1996–1997 suggest that the water bodyis essentially decoupled from climatic forcing duringmuch of the year by ice cover, and that nearly allimportant physical, chemical, and biological pro-cesses in the lake are affected more by freezing andthawing processes than by direct climatic forcing.The undoubted sensitivity of the lake to climaticforcing is therefore indirect, being concentrated onthe periods during which freezing, and especiallythawing, take place. Due to the presence of the highcliff face to the south, the lake is shaded to a largeextent from direct solar radiation, so that the thaw-ing of the ice is slow and heterogeneous, with a longtransitional period of partial ice cover which keepslake surface temperatures low regardless of the pre-vailing air temperature. The productivity and eco-logical dynamics of the lake appear to be dominatedby the length of the ice-free season, and not – or onlyto a minor degree – by thermal stratification. Thereis evidence to suggest that the lake does not thaw atall in some years. The dominance of ice cover mayappear to call into question the usefulness of Hagel-seewli as a repository of climatic information as far asa direct association with air temperature is con-cerned. However, Hagelseewli demonstrates well thecomplexity of processes that must be taken intoaccount when attempting to link sediment data tosynoptic climate in high mountain lakes, and theimportance of understanding the role played by localtopography and by the dynamics of the freezing andthawing of the ice cover. Any climatic signalsarchived in the sediments of Hagelseewli can beexpected to reflect the length of the ice-free seasonrather than the prevailing air temperature directly.Hagelseewli was never entirely mixed during theperiod of observation, although partial mixingoccurred during the short ice-free period, when oxy-gen-rich water mixed down to about the 10-mdepth. The dynamics of the lake are at their mostenergetic during the time of ice break-up, when theinput of large amounts of ammonium, but not ofphosphate, was observed, followed by an increase inoxygen concentrations and in pH. The ammoniuminput to the water column might take place viaatmospheric deposition and snowmelt, possiblyincluding a component from the soil underlying thesnow. Dissolved phosphate in the lake water origi-nates mainly from redissolution from the sediments.During the ice-free period, algal uptake reduces dis-solved phosphate concentrations to below the limitof detection. Preliminary sediment trap results sug-gest the hypothesis that the ratio of planktonic toperiphytic diatoms may indicate periods of changingice-cover duration. Future results of sediment analy-ses will reveal whether this hypothesis is valid andwhether the ratio of planktonic to periphytic diatomspecies may represent a key proxy for use in palaeocli-mate reconstructions in lakes of this kind.

Anthropogenic radionuclides in sediments in the NW Pacific Ocean and its marginal seas: results of the 1994–1995 Japanese–Korean–Russian expeditions

Assessment of contamination of anthropogenic radionuclides from past dumping of radioactive waste in areas of the Okhotsk Sea, NW Pacific Ocean and the Sea of Japan/East Sea has been performed. Two joint Japanese–Korean–Russian scientific expeditions were carried out in 1994–1995, where seawater and seabed sediments were samples from 22 sites. Results of sediment analysis are reported here, where concentrations of 90Sr, 137Cs, 238Pu, 239,240Pu and 241Am in surface layer and bulk sediments showed on large spatial variations, ranging between <0.04 and 0.75 Bq kg −1 dry wt., <0.2 and 7.2 Bq kg −1 dry wt., <0.001 and 0.08 Bq kg −1 dry wt., 0.006 and 2.0 Bq kg −1 dry wt., 0.03 and 1.8 Bq kg −1 dry wt., respectively. However, the concentrations are comparable with those found in reference sites outside the dumping areas and they generally fall within ranges previously reported for non-dumping areas of the investigated seas. Estimates of sediment inventories indicated differences in radionuclide load between shelf/slope and basin type sediments as well as dependence on water depth. Except for the shallow areas, most of the inventories of 90Sr, 137Cs and Pu isotopes are still to be found in the water column. Total inventories (in water+sediment) show a surplus of 137Cs and Pu-isotopes compared to expected integrated global fall-out deposition, which is consistent with previous observations in non-dumping areas in the seas investigated. Analysis of sediment 238Pu/ 239,240Pu activity ratios showed values in accord with that of global fall-out. Analysis of radionuclide depth distributions in core samples from areas of the Sea of Okhotsk showed sedimentation rates of 0.2–0.4 g cm −2 year −1 and 0.03 g cm −2 year −1 for shelf and basin areas respectively, which is similar to values found in the Sea of Japan/East Sea. Depth profiles of 90Sr, 137Cs and Pu isotopes in cores of the basin area indicate a typical delay compared to the input records of global fall-out.

Algorithm for treatment of sedimentation curves in particle size analysis for powders

An algorithm is suggested for calculating the particle size distribution in powdered materials from the results of sedimentation analysis in gravitational and centrifugal fields. Comparison of the particle size analysis for a Stokes' suspension of a specific fractional composition shows that the suggested algorithm eliminates a bias of the differential characteristic of the distribution toward an increase in particle size.

Determination of plutonium 240/239 ratios in Lake Ontario sediments

A thermal ionization mass spectrometric procedure was developed for determination of 240/239 ratios in subpicogram quantities of plutonium (Pu), and was applied to Pu extracted from Lake Ontario sediment. The detection limit was ∼ 4 fg of Pu and the precision of 240/239 ratio measurement was ∼ 7% in the 0.07–0.42 pg range. Results of sediment analyses at various depths showed in all cases 240/239 ratios near the mean global fallout value of 0.176 ± 0.014. The lack of variability of the ratios with depth negated the use of Pu, present in excess in the near-surface samples due to leakage from a nearby reprocessing plant, as a geochronological meter. The 240/239 ratio of the leakage Pu appeared to be very similar to that of fallout Pu.

The properties of magnesia powders for the hot welding process

A number of powders derived from MgO calcined at various temperatures within the range 770–1770 K was submitted to the treatment usually used in preparation of the batches to welding process (hot-pressing in the presence of liquid salt phase). Changes in powders characteristics during this treatment have been discussed based on results of sedimentation analysis and specific surface area measurements (BET method). The samples made of these powders with and without salt addition (CaCl2LiCl eutectic mixture) were examined using mercury porosimetry and SEM. It has been shown that powder characteristics and the presence of liquid salt phase essentially influence the results of densification process. Sharp differences have been discovered in apparent densities and total amounts of open pores between the samples hot-pressed with and without salt additions. The former reached densities of about 85% theoretical and the latter were usually lower than 50%.

Purification and properties of acyl-CoA oxidase from rat liver.

Acyl-CoA oxidase, the initial enzyme of the peroxisomal beta-oxidation system, was purified from rat liver. The final preparation was judged to be nearly homogeneous from the results of sedimentation analysis. Ultrogel AcA-34 column chromatography, and phosphocellulose column chromatography. The molecular weight of the enzyme was determined to be 139,000 by the sedimentation equilibrium method and Ultrogel AcA-34 column chromatography. The S020,W of the enzyme was 7.85S. Three protein components, A, B, and C, were found in the enzyme preparation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (molecular weights, 75,500, 50,100, and 19,000) and high-pressure liquid chromatrography in the presence of 6 M guanidine . HCl (molecular weights, 71,900, 51,700, and 20,500). It was concluded that components B and C were formed from component A, probably by proteolytic cleavage, based on the result of amino acid analysis of each component. The pI of the enzyme was 9.2. The enzyme contained FAD as a prosthetic group, and exhibited absorption maxima at 278, 378, and 450 nm. The FAD content was 1.22 mol/mol of enzyme. When palmitoyl-CoA was added to the enzyme solution under anaerobic conditions, the bound FAD was reduced. The Km values were lower for C14 to C18 acyl-CoA's than for others tested, whereas Vmax values were roughly the same for C8 to C18 acyl-CoA's. The Km value for O2 was 5 microM. The optimal pH was 8. 3-Ketohexadecanoyl-CoA inhibited the enzyme (Ki=0.47 microM), forming a charge-transfer complex with the enzyme.

Polyadenylated Virus-specific RNA in Baby Hamster Kidney Cells, Transformed by Polyoma Virus

RNA from a clone of polyoma virus-transformed hamster cells was fractionated by chromatography on oligo(dT)-cellulose. The proportion of virus-specific RNA in the polyadenylated and non-polyadenylated fractions was determined by hybridization of the labelled RNA with excess purified polyoma DNA, immobilized on filters. Seventy to 80% of the virus-specific RNA in both polysomal and total cell RNA was found in the polyadenylated fraction. Since it has been shown previously that more than 65% of the total virus-specific RNA is restricted to the nucleus in this cell line, these results indicate that a high proportion (at least 53%) of the nuclear virus-specific RNA is polyadenylated. The sedimentation profile of total polyadenylated virus-specific RNA in dimethyl sulphoxide was comprised mainly of a broad band with a median sedimentation coefficient about 26S (relative to 28S rRNA). This profile was similar to that of total nuclear, and not cytoplasmic, virus-specific RNA. To estimate the intramolecular proximity of virus-specific sequences to poly(A), total RNA was subjected to limited thermal scission to an average mol. wt. similar to that of mRNA. The RNA remaining attached to poly(A) was then isolated, using oligo(dT)-cellulose. It was found that 65% of the virus-specific RNA that was originally attached to poly(A) was released by the thermal scission. Most of the virus-specific sequence within polyadenylated RNA molecules therefore must have been located at some distance from the polyadenylated 3'-terminus. This observation, together with the results of sedimentation analysis, can most simply be explained by postulating the existence of 'hybrid' RNA molecules containing a host-specified sequence located between a virus-specific sequence and the 3'-terminal poly(A).

Isolation of cold-sensitive Chinese hamster cells.

Six cold-sensitive variants have been isolated from Chinese hamster ovary cells by the BUdR-visible light selection technique. The properties of one of these lines have been studied in detail. This line stops dividing immediately after a shift from 39 degrees C to 33 degrees C though its doubling time at 39 degrees C is only slightly longer than that of wild-type cells. The rates of DNA and protein synthesis are severely reduced at 33 degrees C, but the rate of RNA synthesis is not significantly different from wild-type cells. This line may be defective in protein synthesis, but the results of sedimentation analysis indicate that it probably has normal ribosomal subunit assembly.

The modification of nucleosides and nucleotides: IV. The reaction of semicarbazide with nucleic acids

1. Cytidine residues of yeast RNA have been specifically converted into semicarbazide derivatives without altering any other bases. In this reaction the C-4 amino groups of cytidine residues were converted into a semicarbazido group. 2. tRNA modified with semicarbazide was completely hydrolysed to nucleoside 5′-phosphate with snake venom phosphodiesterase (orthophosphoric diester phosphohydrolase, EC 3.1.4.1). The base composition of the tRNA was estimated after separation of the nucleotides by ion-exchange column chromatography. A quantitative estimation of the modified cytidine residues in the tRNA was achieved by this method. 3. The results of sedimentation analysis and gel filtration of the tRNA modified with semicarbazide indicated that no splitting of the internucleotide bonds of the RNA occurred during the reaction. 4. The temperature-absorbance relationship plotted for the modified tRNA indicated that the secondary structure in the tRNA decreased with increasing extent of modification. 5. The rate of this modification reaction is low when cytosine groups are highly hydrogen bonded (double-stranded DNA). 6. A simple method for estimating the extent and rate of the modification reaction of cytidine residues in nucleic acids is proposed. In this procedure the specific light absorption of the 4-deamino-4-semicarbazidocytidine residue in the range 300–340 mμ at pH 13 is followed.

Untersuchungen zur Geochemie des Bleis

After discussing literature on the geochemical distribution of lead, a quantitative spectrochemical method is described (0.01% Bi standard). The sensitivity of 0.0001% Pb is attained by relative concentration of light volatile elements with a double-arc instrument. In this investigation more than 500 analyses for lead of representative samples are discussed (more than 250 own determinations). During the last 3.3 . 10 9 years the total amount of lead of the earth's crust has increased only by 20% from radiogenic sources. The average lead content of micas and potassium feldspars (~0.0025%) surpasses that of the lithosphere (0.0015%). Remarkable amounts of 0.010% Pb are gathered in the feldspars of pegmatites. Olivine and quartz (excepting rose-quartz) have the lowest contents (~0.0001% Pb); those are expected after their structural properties. Lead replaces potassium in its structural positions owing to similar ionic dimensions. In the course of magmatic differentiation the proportions K/Pb and Ba/Pb are increasing, only excepting some late minerals. Adulars, feldspathoids and zeolites are favoured in the replacement of K, Na and Ca. The feldspars contain the main lead content of eruptive rocks. The following figures are average Pb abundances of a great number of samples: granite 0.0019%, granodiorite 0.0015%, diorite 0.0010%, basalt 0.0006%, ultrabasic rocks 0.0003%. Galena seems to be a very rare compound in normal rocks. The behaviour of lead in rock alteration (weathering, mobilization, concentration, etc.) is discussed. Factors for concentration are low solubility (PbS, Bleiphosphat adsorption (clay minerals, Mn hydroxides, ferric hydroxides) and action of organisms (foraminiferae, plants, etc.). The clay minerals contain the bulk of lead in sediments. The relative high contents of Pb, Zn and Cu of pelagic sediments cannot have been derived entirely from continental weathering. It must be assumed that a part is due to volcanic exhalations. The following averages are results of sediment analyses: nonpelagic argillaceous rocks 0.0020%, deep-sea clays (Atlantic Ocean) 0.0043%, deep-sea clays (Pacific Ocean) 0.014%, sandstones 0.0007%, limestones and dolomites 0.0009% Pb. Part of the lead content of metamorphic rocks can be derived from their parent material. It increases from greenschists, amphibolites, granulites (0.0010%), to mica-schists and gneisses (0.0023% Pb). A number of lead analyses from specific minerals of metamorphic rocks are reviewed. Natural environments very rarely permit the formation of Pb ⃜ . The Goldschmidt rules on the relationships between distribution of an element and its ionic dimensions and ionic charge give a sufficient explanation of most geochemical characteristics of lead.