Lead and zinc deposits of Northwestern Illinois,

Mode of access: Internet.

Geology of parts of the upper Mississippi Valley zinc-lead district.

Issued as separate chapters A-I.

Electrochemical investigation of liquid amalgams of thallium, indium, tin, zinc, cadmium, lead, copper, and lithium.

"Contributions from the Chemical Laboratory of Harvard College."

Principles of mining: valuation, organization and administration; copper, gold, lead, silver, tin and zinc,

Mode of access: Internet.

Lead and zinc problems. Hearings, Eighty-seventh Congress, first session, on problems pertaining to the lead and zinc industry and consideration of S. 1747. May 4-5, and July 25, 1961.

Mode of access: Internet.

Preliminary report on the lead and zinc of Oklahoma /

Mode of access: Internet.

Piezoelectric and dielectric properties of Ce substituted La2Ti2O7 ceramics

The ferroelectric and dielectric properties of cerium (Ce) substituted La2Ti2O7 (LTO) have been investigated. Single phase, dense La2-xCexTi2O7 (x=0.15, 0.25, 0.35) ceramics were prepared by spark plasma sintering. The solubility limit of Ce in La2-xCexTi2O7 was found to be between 0.35 and 0.5. The a-, b- and c-axes of the unit cell decrease with increasing Ce substitution. The Curie point (Tc) of La2-xCexTi2O7 (x=0, 0.15, 0.25, 0.35) decreases and dielectric constant and loss increase with increasing Ce substitution. Cerium can increase the d33 of La2Ti2O7. The highest d33 was 3.9±0.1pC/N for La1.85Ce0.15Ti2O7 textured ceramic. © 2012 Elsevier Ltd.

Evaluation of blood zinc, calcium and blood lead levels among children aged 1-36 months

Background: Early childhood lead exposure is associated with numerous adverse health effects. Biomonitoring among susceptible populations, such as children, has not been previously conducted. The aim of the study is to evaluate the blood lead (Pb) and total blood calcium (Ca) levels; blood zinc (Zn) levels. Methods: A cross-sectional study was designed to collect healthy children age 1-36 months (Mean ± SD: 1.5 ± 0.6 age, 60% boys) in the study from January 2010 to September 2011. Results: The overall mean blood Pb levels were 42.18 ± 12.13 μg/L, the overall mean blood Zn and total blood Ca concentrations were 62.18 ± 12.33 μmol/L and 1.78 ± 0.13 mmol/L, respectively. The prevalence of elevated blood Pb levels in all children was 1.3%. A significant difference was found between female and male subjects for the blood Pb and Zn. After controlling for gender and age, there was a weak positive correlation between total blood Ca and Zn level. Conclusions: The blood Pb levels had a significant negative correlation with total blood Ca level after adjusting for age and gender, and these findings suggest that Pb had effect on positive blood Zn and total blood Ca levels; parents should pay more attention to the nutrition of girls.

Association of dental enamel lead levels with risk factors for environmental exposure

OBJECTIVE: To analyze household risk factors associated with high lead levels in surface dental enamel. METHODS: A cross-sectional study was conducted with 160 Brazilian adolescents aged 14-18 years living in poor neighborhoods in the city of Bauru, southeastern Brazil, from August to December 2008. Body lead concentrations were assessed in surface dental enamel acid-etch microbiopsies. Dental enamel lead levels were measured by graphite furnace atomic absorption spectrometry and phosphorus levels were measured by inductively coupled plasma optical emission spectrometry. The parents answered a questionnaire about their children's potential early (05 years old) exposure to well-known lead sources. Logistic regression was used to identify associations between dental enamel lead levels and each environmental risk factor studied. Social and familial covariables were included in the models. RESULTS: The results suggest that the adolescents studied were exposed to lead sources during their first years of life. Risk factors associated with high dental enamel lead levels were living in or close to a contaminated area (OR = 4.49; 95% CI: 1.69;11.97); and member of the household worked in the manufacturing of paints, paint pigments, ceramics or batteries (OR = 3.43; 95% CI: 1.31;9.00). Home-based use of lead-glazed ceramics, low-quality pirated toys, anticorrosive paint on gates and/or sale of used car batteries (OR = 1.31; 95% CI: 0.56;3.03) and smoking (OR = 1.66; 95% CI: 0.52;5.28) were not found to be associated with high dental enamel lead levels. CONCLUSIONS: Surface dental enamel can be used as a marker of past environmental exposure to lead and lead concentrations detected are associated to well-known sources of lead contamination.

Structural and optical properties of rare earth-doped (Ba(0.77)Ca(0.23))(1-x)(Sm, Nd, Pr, Yb)(x)TiO(3)

The structural, dielectric, and vibrational properties of pure and rare earth (RE)-doped Ba(0.77) Ca(0.23)TiO(3) (BCT23; RE = Nd, Sm, Pr, Yb) ceramics obtained via solid-state reaction were investigated. The pure and RE-doped BCT23 ceramics sintered at 1450 degrees C in air for 4 h showed a dense microstructure in all ceramics. The use of RE ions as dopants introduced lattice-parameter changes that manifested in the reduction of the volume of the unit cell. RE-doped BCT23 samples exhibit a more homogenous microstructure due to the absence of a Ti-rich phase in the grain boundaries as demonstrated by scanning electron microscopy imaging. The incorporation of REs led to perturbations of the local symmetry of TiO(6) octahedra and the creation of a new Raman mode. The results of Raman scattering measurements indicated that the Curie temperature of the ferroelectric phase transition depends on the RE ion and ion content, with the Curie temperature shifting toward lower values as the RE content increases, with the exception of Yb(3+) doping, which did not affect the ferroelectric phase transition temperature. The phase transition behavior is explained using the standard soft mode model. Electronic paramagnetic resonance measurements showed the existence of Ti vacancies in the structure of RE-doped BCT23. Defects are created via charge compensation mechanisms due to the incorporation of elements with a different valence state relative to the ions of the pure BCT23 host. It is concluded that the Ti vacancies are responsible for the activation of the Raman mode at 840 cm(-1), which is in agreement with lattice dynamics calculations. (c) 2011 American Institute of Physics. [doi:10.1063/1.3594710]

Microwave dielectric permittivity and photoluminescence of Eu(2)O(3) doped laser heated pedestal growth Ta(2)O(5) fibers

We report the microwave dielectric properties and photoluminescence of undoped and europium oxide doped Ta(2)O(5) fibers, grown by laser heated pedestal growth technique. The effects of Eu(2)O(3) doping (1-3 mol %) on the structural, optical, and dielectric properties were investigated. At a frequency of 5 GHz, the undoped material exhibits a dielectric permittivity of 21 and for Eu(2)O(3) doped Ta(2)O(5) samples it increases, reaching up to 36 for the highest doping concentration. Nevertheless, the dielectric losses maintain a very low value. For this wide band gap oxide, Eu(3+) optical activation was achieved and the emission is observed up to room temperature. Thus, the transparency and high permittivity make this material promising for electronic devices and microwave applications. (c) 2008 American Institute of Physics.