Influences of Inhibitor and Firing Temperature on Efflorescence Reduction of Clay Products

For ceramic industry, efflorescence is undesirable and cannot be completely eliminated from the finished products. The efflorescence is caused by soluble salts in the raw material and mostly appears as white deposit at the product’s surface. In this research, the removal of sulfate in the raw materials was studied. In addition, the sulfate ions were immobilized by forming a water-insoluble compound. The sulfate ions in the raw materials and fired products were extracted by distilled water, and the concentration was determined by using a UV-visible spectroscopy following the ASTM C1580-09 standard. Three sources of the raw materials from Tambon Suan Phung, Ratchaburi, Tambon Mae Win and Mae Ta, Chiang Mai, were analyzed for sulfate concentrations. The clay from Tambon Suan Phung, Ratchaburi which had the highest sulfate concentration was selected for further study on the effect of inhibitor and firing temperature on efflorescence inhibition. To reduce solubility of the sulfate, three kinds of inhibitor, i.e. barium chloride, barium carbonate and barium hydroxide, were added into the raw material at various concentrations, i.e. 0.5, 1.0, 1.5 and 2.0 wt% and homogeneously mixed by ball milling followed by the addition of distilled water to prepare the clay slip. The clay products were mold casted to 1 x 1 x 3 inch3 in size. Then, they were fired at 800, 900 and 1000 °C. It has been revealed that the addition of barium carbonate at 2 wt%, which is the highest amount employed in this study, and firing temperature of 900 °C resulted in least sulfate leaching due to the formation of water-insoluble barium sulfate. To perform a field test, the fired samples with and without the addition of barium carbonate were immersed in water for 4 months. The efflorescence was observed on the sample without barium carbonate within the 1st month. In contrast, with the addition of barium carbonate, no efflorescence was observed after testing for 4 months.

Characterization of White and Black Deposits on the Surface of Korean Stone Cultural Heritages

White and black deposits have been frequently observed on the surface of Korean stone cultural heritages, and they are considered as damage factors in both conservation and esthetic points of view. In order to set up the appropriate conservation remedy, it is important to know their origins, characteristics, and compositions. In this study, optical and scanning electron microscopes (SEMs) equipped with an energy-dispersive spectrometer (EDS) and X-ray diffractometer were employed to determine the white and black deposits. It was found that both deposits consisted mainly of calcium carbonate (calcite) and calcium sulfate (gypsum). The calcite and gypsum were characterized by bladed, rhombohedral, tabular, and amorphous morphologies under a SEM. The black deposit was not only composed of calcite or gypsum, but also accompanied amorphous and irregular matrix. SEM-EDS analysis revealed an abundance of silicon, aluminum, iron, phosphorus, and carbon on the matrix, which were major elements of soil, atmospheric deposits, and organisms. The white deposit, on the other hand, barely contained those coloring substances. These salts and deposited substances were caused by chemical reaction and physical adhesion between rock-forming minerals, lime mortar, sulfur in polluted air environment, soil dust, and microorganisms.

Value of indicators for assessing recent mating in brachyuran crabs

Methods for assessing the occurrence and recency of mating are important for the management and conservation of exploited brachyuran crabs. Using multiparous females of the snow crab Chionoecetes opilio, we evaluated by experiment the efficacy of three indicators of recent mating: a white deposit in the spermathecae, extended mate-guarding, and fresh grasping marks on the female pereiopods. This was done by contrasting sperm counts between the left and the right spermatheca of females that were exposed to males with the right gonopod ablated, at treatment sex ratios of 20[female]:3[male ] or 50[female]:3[male ]. We expected that sperm reserves would be balanced between the two spermathecae of non-mated females and larger in the right than in the left spermatheca of mated females. Although no mating indicator was infallible, the presence of a white deposit was the most accurate because it maximized the median difference of sperm counts between the two spermathecae for the group of presumably mated females and minimized it for the group of presumably non-mated females. The use of grasping marks overestimated the mating frequency and resulted in the misclassification of a large proportion of females. Extended mate-guarding was a slightly better mating indicator than grasping marks, but it is not practical for field studies. Classification errors associated with each indicator can be explained mostly by female and male behaviours and may vary in magnitude with sociosexual context.

Photolysis of SiH4 by the Third Harmonic of a Nd:YAG Laser at 355 NM

The photolysis of silane (SiH4) was carried out using the third harmonic of a Nd: YAG laser at 355 nm, at a fixed SiH4 pressure of 350 Torr, varying the laser energy fluence in the range of 30–300 Jcm-2. The emission spectra indicates that the photofragments formed are SiH2, SiH, Si, H2, and H. The (A1B1-X1A1) transitions at 552.7 nm, 525.3 nm, 505.6 nm, and 484.7 nm of SiH2 are due to a two photon absorption process. The (A2Δ-X2π) transitions of SiH at 425.9 nm, 418 nm, 414.2 nm, 412.8 nm and 395.6 nm are due to a three photon absorption process. The brownish white deposit on the cell windows indicates the presence of amorphous silicon (a:Si-H). The two atomic lines of Si(4s1P0→ 3p21D2) at 288.1 nm, and (4s3Pj→ 3P3Pj) at 251.6 nm are observed. The atomic Si transitions are due to a three photon absorption. We observed seven transitions due to molecular hydrogen at wavelengths 577.5 nm, 565.5 nm, 534.4 nm, 542.5 nm, 471 nm, 461.7 nm, and 455.4 nm. These bands are due to a four photon absorption proc6ss. In addition to the molecular bands we also observed hydrogen atomic lines Hβ, Hγ and Hδ.

Mineralization and biodegradation of CSF shunting systems

✓ The mineralization and biodegradation of cerebrospinal fluid shunting systems were studied using material from 25 shunts that had been implanted for between 6 days and 10 years. New unused materials were also examined for comparison. Surface changes in six systems could be observed under an operating microscope. Substantial quantities of a white deposit had adhered to the tubing in four of the shunts. These changes were most advanced in the galeal penetrative portion of the shunts and are believed to have been caused by mechanical stress. Scanning electron microscopic analysis revealed surface wrinkles, microscopic holes, and tiny particles, suggesting deterioration of the material itself. An energy-dispersive analysis using x-rays demonstrated that the surface deposits were due to mineralization of calcium phosphate and that the tiny particle growth was aluminum. These changes may be a consequence of the degradation of silicone rubber. A discriminant analysis of the mineralization was carried out; thus, the age of the host and the duration of system implantation could be correlated with the incidence of mineralization (p < 0.1). A measurement of the physical properties showed progressive change with a remarkable deterioration in systems implanted for more than 5 years.

CONTROL OF THE SIX-SPOTTED LEAFHOPPER, MACROSTELES FASCIFRONS, AND ASTER YELLOWS ON HEAD LETTUCE IN MANITOBA

Malathion, Sevin® (1-naphthyl N-methylcarbamate) and Bayer 39007 (o-Isopropoxyphenyl methylcarbamate) were tested in the field for the control of the six-spotted leafhopper, Macrosteles fascifrons (Stål), and protection of lettuce from aster yellows in Manitoba in 1960 and 1961. Malathion at 1 pound per acre at 3-day intervals and at 2 pounds per acre at 4-day intervals controlled the leafhopper and protected the lettuce from aster yellows. At 2 pounds per acre at 6-day intervals malathion was less effective against the leafhopper but still provided adequate protection against aster yellows. Sevin at 1 and 2 pounds per acre at 6-day intervals and Bayer 39007 at 1 pound per acre at 3- and 6-day intervals were as effective as malathion at 1 pound at 3-day intervals. Severe infestations of aphids developed after the use of Sevin; Bayer 39007 left an objectionable white deposit on the lettuce. In early spring crops, treatments that were started 4 weeks after crop emergence were as effective as those started at crop emergence. In summer crops, treatments started 2 weeks after crop emergence were as effective as those started at crop emergence. Nine days after the last of 15 applications of malathion there was a residue of less than 0.5 p.p.m. on the lettuce.

Nitrogenous Excretion in Crocodiles

1. In Crocodylus niloticus the liquid urine contains a white deposit. In the present study both the liquid and the deposit have been analysed. 2. For the liquid urine, the following values for percentage of total nitrogen have been found: ammonia, 66.8%; urea, 12.5%; uric acid, 2.3%. 3. For the deposit the corresponding figures are: ammonia, 6.0%; uric acid, 88.6%; urea absent. 4. From the relative proportions of liquid urine and deposit it is calculated that the total excretory nitrogen (liquid + solid) is distributed as follows: ammonia, 25.4%; urea, 4.5%; uric acid, 68.5%. 5. Crocodiles are thus ammono-uricotelic. The view that alligators are ammonotelic derives from analysis of liquid urine only. Uric acid deposits have been noted in the urine of reptiles of many orders and it is probable that they occur also in the urine of alligators.

Human foot perspiration and upper leather

The suspicion, long entertained, that the grey or white deposit on a large amount of worn footwear, returned with complaint of “spewing salt” on the vamps, had its origin in the action of foot perspiration, has been confirmed during the last ten years.

Notes on the eggs and early development of some species of Oxyuridæ

Although Oxyuris vermicularis occurs very frequently in children, material from which to study the early development, mature female worms, was difficult to obtain.Specimens were found both in the normal stool and in the stool after treatment with santonin. Egg-laying began as soon as the worms came into contact with air; those which happened to be on the surface very quickly became surrounded by a white deposit of eggs and the worms themselves became reduced to fine threads, which were difficult to detect: Egg-laying was also induced by bringing females into water at body temperature.