Amount Of Organic Substances Research Articles

A polymer complex solution route to the low-temperature synthesis of tetragonal Zr0.88Ce0.12O2 with a reduced amount of organic substance

Abstract Powders of composition Zr0.88Ce0.12O2 were synthesized at reduced temperatures (600–800°C) by a polymer complex solution (PCS) method using polyvinylalcohol (PVA) and by the Pechini-type in situ polymerizable complex (IPC) method. Both methods produced transparent organic polymer complex gels without any precipitation, which after heat treatments at temperatures above 600°C converted to a compositionally homogeneous tetragonal form of Zr0.88Ce0.12O2. It was demonstrated that the PVA-based PCS method overcame a weakness of the IPC method; i.e., the amount of organic substance required for the PVA-based PCS method is less than that required for the IPC method by a factor of about 20.

Industrial analysis: metals, chemicals and advanced materials

This Atomic Spectrometry Update is the latest in an annual series appearing under the title ‘Industrial Analysis'. This year there have been several changes to the structure of the review. Some rearrangement of the Petroleum and petroleum products section, and some refocusing of the Chemicals section, has taken place. Also the Semiconductor section has been given a wider remit and is now called Semiconductors and conduction materials. It is hoped that these changes will meet with the approval of regular readers of this review and the authors and review co-ordinator would appreciate any constructive comments that may come to mind.In the area of organic and non-metal analysis there has been an increase in the use of indirect techniques for quantification of the organic compound of interest, i.e., the analysis of either complexed or inherent element by atomic spectrometry methods to give an estimation of the amount of organic substance. Also microwave digestion methodologies have been used in some interesting applications.There has been a large increase in the number of publications and conference presentations in the area of high purity metal analysis, and not just for the precious metals. The papers covered in this review concentrate on both the analysis of purity (difficult with respect to standards) and trace impurities (difficult with respect to matrix effects and sensitivity).Not much real novel work was encountered in the fields of the advanced materials sections and the avid reader will notice that these sections may be slightly shorter than other years, especially the Ceramics and refractories section, although the systematic analysis of REEs by Chinese workers continues.In general, improvements in sample preparation and instrument sensitivity have contributed most to the work covered by this year's review, especially in the nuclear and semiconductor industries, where the advances in ICP-MS instrumentation are now yielding sub-femtogram detection limits without preconcentration steps. If only we all could work with dark current blanks.

Vegetation Composition Determines Microbial Activities in a Boreal Forest Soil.

Abstract Forest soil ecology was studied in Fennoscandinavian dry Scots pine forests grazed by reindeer to varying extents (ungrazed, lichen-dominated-sites; grazed sites; and bryophyte-dominated sites). We hypothesized that the productivity parameters of the site (i.e., tree growth and soil nutrient concentrations), the vegetation composition, and the microbial activities are directly correlated. Since the productivity of the lichen-dominated ecosystem is low, microbial activities are assumed to be naturally low. Grazing was expected to decrease both the amount of Scots pine fine roots and the soil microbial activities. Several variables on the characteristics of the soil microbial community, Scots pine fine roots, soil nutrients, and tree growth were studied in relation to vegetation composition by using non-metric multidimensional scaling (NMDS). Basal respiration (Bas), metabolic quotient of the microbial community (qCO2), and pine fine root parameters increased toward the ungrazed, nutrient-poor, lichen-dominated sites, which were grouped at one end of the first axis in the NMDS ordination. Soil nutrient and tree growth parameters and thickness of the humus layer increased toward bryophyte-dominated sites, which were grouped at the other end of the first axis in the ordination. The grazed sites fell between them. These were characterized by lower Bas and qCO2 values and longer lag, compared to ungrazed lichen- or bryophyte-dominated sites, probably due to decreased carbon input and microclimatic change (the soil without lichen carpet is exposed to direct sunlight and wind). Microbial biomass (Cmic), fungal biomass (ergosterol concentration), and the specific growth rate (µCO2) were not related to vegetation ordination. The high fine root production is the most plausible explanation for the high microbial activities at nutrient-poor, lichen-dominated sites, which produce qualitatively poor and slowly decomposing litter, as fine roots secrete considerable amounts of organic substances. At bryophyte-dominated sites, the higher soil nutrient concentrations and the higher production of easily decomposable substrates are likely to maintain the microbial activities.

98/01278 Utilization of coal ash as fine aggregates: Hisaka, M. and Mano, T. Konkurito Kogaku, 1996, 34, (7), 102–103. (in Japanese)

Mesocyclops leukarti of zooplankton propagates excessively in eutrophic water body and it cannot be effectively inactivated by the conventional drinking water treatment process. In order to tackle this problem, a study of removal effect on Mesocyclops leukarti with chlorine dioxide in a waterworks was performed. The results showed that Mesocyclops leukarti could be effectively removed from water by 1.0 mg/L chlorine dioxide preoxidation combined with the conventional drinking water treatment process. Higher oxidizability and molecular state of chlorine dioxide in water is the key to the inactivation of Mesocyclops leukarti. The chlorite, disinfection by-products (DBPs) of chlorine dioxide, was stable at 0.45 mg/L, which is lower than that critical value of the USEPA. GC-MS examination showed that the quantity of organic substance in the water treated by chlorine dioxide obviously decreased. Ames test further revealed that the mutagenicity was reduced by chlorine dioxide with respect to prechlorine. The propagation of Mesocyclops leukarti can be inactivated effectively and safely by chlorine dioxide pre-oxidation.

Low molecular weight organic acids released from roots of durum wheat and flax into sterile nutrient solutions

Knowledge of the composition and quantity of organic substances released from roots of different plant species is necessary for understanding the chemical and biological processes in the rhizosphere. The present study was undertaken to quantify low molecular weight organic acids (LMWOAs) released from roots of five cultivars/lines of durum wheat (Triticum turgidum var. durum L.): Kyle, Sceptre, DT618, DT627, and DT637 and four cultivars/ lines of flax (Linum usitatissiumum L.): Somme, Flanders, AC Emerson, and YSED 2. Plants were grown in sterile nutrient solution cultures and amounts of organic acids exuded by roots were analyzed by gas chromatography. The LMWOAs varied significantly among both durum wheat and flax cultivars and oxalic, malonic, fumaric, succinic, acetic, malic, citric and tartaric acids were detected in root exudates of both species. Generally, oxalic and acetic acids were predominant in durum wheat exudates and oxalic, acetic and malic acids were predominant in flax root exudates. High oxalic acid concentrations occurred in root exudates of durum wheat cultivars DT627 and DT637, and flax cultivar YSED 2. Compared with the other durum wheat cultivars, Kyle released the lowest total amount of LMWOAs, whereas among the flax cultivars, YSED 2 had the highest total amount of acids secreted from roots. The data showed that the release of LMWOAs from roots was cultivar dependent. The results provide valuable background information for studying the role of root exudates in soil‐plant relationships.

Changes of adsorption capacity and pore distribution of biological activated carbon on advanced water treatment

Several problems such as unpleasant odor, taste and toxic halogenated organic compounds which are produced by the reaction of organic substances with chlorine that is used for disinfection have occurred in water purification plant for drinking water. Advanced water treatment with biological activated carbon (BAC) has been focused on, but there are few papers about pore volume decrease of activated carbon in BAC. In this study, the changes in cumulative TOC removal and pore volume distribution for two types of activated carbon from a bench-scale apparatus and a mini-column apparatus, to which river water was supplied after coagulation-sedimentation for a period of over 1200 days, were investigated. Adsorption abilities decreased considerably after ca 1000 days and the activated carbons became like sand. The cumulative TOC removals by the adsorption effect were asymptotic to constant values for each empty bed contact time. Though the removal efficiencies for both the activated carbons were approximately equivalent, the pore volume decreases were not uniform. The volume of smaller pores under 2 nm in diameter mainly decreased. Accumulations of minerals such as aluminium and calcium were small, and the pore volume decreases were mainly caused by the accumulation of organic substances. Almost all of the organic substances that accumulated in the activated carbon could be extracted by sodium hydroxide solution. The mean density of the organic substances that accumulated in the activated carbon was estimated to be 0.91 g/ml. Since the pore volume decrease of the activated carbon was small compared with the removal amounts by the adsorption effect, a large amount of organic substances that had adsorbed once disappeared and the pore volume of the activated carbon was regenerated.

Use of high performance size exclusion chromatography to monitor the dynamics of water-soluble organic substances during the decomposition of plant residues in soil

Abstract Soils amended with plant residues (20 g kg-1 soil) were incubated for 56 d at 25°C under upland conditions, and water extracts were obtained periodically. The decomposition process was monitored using high performance size exclusion chromatography (Asahipack GS-220M column) for the extracts detected by absorbance at 280 nm. Two types of soils (Udifluvent and Melanudand) and three kinds of plant residues (rapeseed meal, orchard grass shoots, and rice straw) were used for the experiment. The rates of decomposition were in the order of rapeseed meal > orchard grass shoots > rice straw, and the decomposition of rice straw caused the immobilization of inorganic N throughout the incubation period. In all the treatments, the amount of water-soluble organic C decreased sharply during the early period of incubation. The amount of organic substances contained in the plant residues rapidly disappeared from the water extract, and simultaneous formation of water-soluble organic substances was observed by high performance size exclusion chromatography. The amount of newly formed organic substances decreased with time. Using polyethylene glycols to calibrate the column, the molecular weight of the UV-absorbing water-soluble organic substances at peak maximum was 1,200 and 500 for the Udifluvent and Melanudand samples without plant residue amendment, respectively. For the newly formed UV-absorbing water-soluble organic substances, the molecular weight at peak maximum was 1,200 regardless of the soil types. However, the molecular weight of the UV-absorbing water-soluble organic substances formed from plant residues in the Melanudand sample tended to decrease during the incubation period.

Mineral Content of the Innermost Enamel in Erupted Human Teeth

It has been said that the innermost enamel of erupted human teeth is either a hyper- or a hypomineralized layer. Using SEM-EDX, in the present study, the Ca and P mineral contents of the innermost 10-15 microns enamel showing a highly negative birefringence (IE-I) were analyzed and compared with those of the adjacent inner enamel (IE-II) in each cuspal-third, mid-coronal, and cervical-third region. The Ca content in the IE-I zone was significantly lower than that in the IE-II zone in the mid-coronal and cervical-third regions, whereas the significant difference of P content was seen only in the cervical-third region. In the other areas, the IE-I zone tended to be lower than the IE-II zone. These significant and no significant differences of Ca and P contents may be due to the difference in the amount of organic substance in the IE-II zone of the three regions, and that of these mineralization rates after eruption of a tooth.

Application of Dynamic Headspace Analysis to Laboratory and Field Arson Investigations

Abstract A dynamic headspace procedure has been adopted to meet the special needs of the forensic scientist engaged in detecting and identifying trace accelerants present in physical evidence recovered from fire scenes. For common accelerants, sorbent trap concentration followed by thermal desorption directly onto a gas chromatographic column enhanced sensitivity by two orders in a magnitude over a static headspace technique. The procedure reduced negative findings 38% and inconclusive determinations 60% relative to static headspace analysis. Air at fire scenes can be drawn through a trap with a portable pump to allow monitoring for trace amounts of organic substances. The trap is then forwarded to the laboratory for analysis. Special precautions in sampling methods, transportation, and storage will be discussed as they relate to assuring the integrity of the collection and analysis of a fire scene atmosphere.

Chemical conversions of petroleum hydrocarbons during biochemical purification in aerator tanks

1. When water containing naphthenic, aromatic, and paraffin hydrocarbons is purified biologically in an aerator tank, 33% of the total amount of organic substances to be purified remains in the purified water and 33% is removed from the tank by air. The remaining organic matter (34%) goes to increase the active sludge and is completely oxidized to form CO2 and H2O. 2. Considerable changes occurred in the composition of the organic matter present in the purified water and in the air (66%): a) the amount of methanol-soluble substances, the oxidation products of hydrocarbons, was nearly doubled; b) there was a marked reduction (by a factor of 7.5) in the content of neutral compounds and their relative amount decreased from 83.4% to 55%; c) owing to the decrease in the content of neutral compounds, that of the strong organic acids, phenolic compounds, and substances more soluble in water than in ether increased; d) a quarter of the neutral compounds was oxidized to form neutral oxygen-containing compounds such as aledhydes, ketones, etc. Only 10% of the initial petroleum hydrocarbons remained in the purified water. 3. Study of the composition of the substances more soluble in water than in ether (group 4) showed that they consisted largely of acids (about 70% were back-titrated with alkali, the pH of an aqueous solution was 3). 4. The strong organic acids (group 7) consist of low-molecular acids of the paraffin series with mean molecular weight 76. 5. The organic compounds of active sludge consist mainly of neutral compounds (95%) and only 5% are methanol-soluble substances (group 1). 6. The extraction of the organic compounds of petroleum -containing water with ether was not accompanied by extraction of substances soluble in chloroform (group 2) or of substances soluble in methanol (group 1). During this process the losses amount to 50% or more.

山中湖における細菌の活動性

The standing crop and the activity of lake inhabiting bacteria were observed in Lake Yamanaka-ko, Yamanashi prefecture. The amount of bacteria of water and mud differs with different basins of one lake. The amount of organic substances in lake bottoms seems to be the most essential factor to decide the productivity of bacteria.The vertical differences in the activity of water bacteria were observed by culture method. The multiplication of bacteria occurred at the surface and the bottom layer in winter, and at the 24 m layers in summer.The vertical differences of bacterial activity were observed in bottom mud. The activity is very high in the surface layer of mud.

An Ecological Study of Mosquitos in Wuhan Area

Field and laboratory studies were made of the mosquitos of the Wuhan area, central China, between June 1947 and March 1948.The following species were collected :Anopheles hyrcanusvar.sinensis, Mansonia uniformis, Armigeres obturbans, Aëdes albopictus, Culex fuscanus, Culex vagans, Culex fatigans, Culex pipiensandCulex tritaeniorhynchus. A brief account is given of the topography and other environmental features of Wuhan.The seasonal incidence and feeding habits of the adults, and the breeding sites favoured by the various species are recorded.Monthly mean figures for rainfall, temperature and humidity are examined in relation to incidence of malaria and abundance of adults and larvae ofAnopheles hyrcanusvar.sinensis. The peak of malaria incidence coincides with that ofAnophelespopulation which occurs two to three months after the peak of rainfall at an average relative humidity of 66 per cent.A chemical analysis of waters from different types of breeding sites was made. Both the total organic nitrogen, and the amount of dissolved oxygen were considerably greater in the breeding site ofArmigeres obturbansthan in those of other genera. A sample of water from a site in which no mosquito breeding was observed contained very much smaller amounts of organic substances and minerals than samples from known breeding sites.Other ecological factors affecting the early stages in their breeding sites are briefly referred to.

Influence of Cathode Rays on Leucocytes of Rabbits.

It is well known that leucocytes are destroyed to a considerable extent if a large portion of an animal is exposed to about an erythema dose of roentgen rays which penetrate into the tissues under the skin. Bucky1 has stated that very soft roentgen rays. “grenz rays,” have a different effect on the leucocytes. According to him, a considerable portion of the leucocytes disappear from the circulating blood immediately after a small area of the skin has been exposed to these rays, which are all absorbed in the first millimeters of tissues, and reappear after a few hours. Cathode rays produced with less than 200 kilo volts are absorbed by the first millimeter of tissue. A very intense dose given to the skin will, therefore, not directly injure the underlying tissues. Such an intense dose can be given in a few seconds. Due to the rapid destruction of tissues a considerable amount of organic substances may be liberated. It is possible that they will be taken up partially by the skin capillaries and thus become ...