Search

Thirty-two computer-based lesson modules in organic chemistry were developed at the University of Texas (Austin) over an 18-month period and evaluated in varying classroom situations for three semesters starting in the Fall of 1972. The modules were designed as supplements to the traditional organic chemistry course of the University. As such, they emphasized tutorial-drill and experiment simulation applications in some of the basic organic chemistry concepts including nomenclature, classes of organic compounds, syntheses, reactions, preparations, laboratory exercises, and spectral interpretations. This paper includes descriptions of the modules together with a summary of their initial use and evaluation. (Author/DGC)

Computers have effected a comprehensive transformation of chemistry. Computers have greatly enhanced the chemist's ability to do model building, simulations, data refinement and reduction, analysis of data in terms of models, on-line data logging, automated control of experiments, quantum chemistry and statistical and mechanical calculations, and information storage including retrieval and the capacity for dynamic visual display. A recent conference addressed itself to the following aims: (1) provide a national forum for the impact of computers on chemistry; (2) encourage more investigation on computers; (3) make known the present status and the potential of computer-assisted instruction (CAI) in chemistry; and (4) inspire further examination of the chemistry curriculum in light of recent advances in computer technology. The conference report is a collection of 80 papers divided into the following categories: data fitting; curve fitting and band analysis of spectra; structure determination; CAI; computer technology in theoretical chemistry; chemistry curriculum development; communications in the field of chemistry; computer control of experiments; the use of A Programing Language (APL) in the undergraduate curriculum; and information systems. (EMH)

This document compares the benefits and risks of breastfeeding in light of recent evidence that mothers' milk contains high levels of chemical contaminants. Information is presented on the occurrence and toxicity of agricultural and industrial chemicals found in breast milk and on the lead, industrial chemicals, nitrates, and bacterial contamination found in cows' milk. Physical and psychological benefits of breastfeeding for the mother as well as psychological, immunological, and anti-allergenic benefits of breastfeeding for the infant are discussed; the benefits of bottle feeding are presented briefly. The composition of formula is discussed and guidelines for choosing a formula are offered. Information is presented on ways to minimize contaminants in the diet and recommendations for government action are offered. Appendices include information on: (1) pesticides in human milk, (2) pesticides in cows' milk, (3) filtration of drinking water, (4) approximate analyses of commonly used infant formulas compared to human and cows' milk, and (5) testing milk for contaminants. A 20-item glossary is also included. (JMB)

Copyright of Congreso Internacional de Investigacion Academia Journals is the property of PDHTech, LLC and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Before entering the market, coated electrodes, as an additional material in the MMAW welding process, must meet the existing regulations and requirements regarding the quality of welds, permissible harmful emissions into the environment and market requirements. In the MMAW welding process, welding fume is generated by the welding process. The emission level or production of welding fume, the method of collecting particles from welding fume and the method of chemical analysis are determined by the standard EN ISO 150011-1. The aim is to obtain a coated electrode with the lowest emission of harmful welding fumes into the environment and with the best welding characteristics. Tests of commercial and experimental electrodes of the same class were performed for the MMAW welding process of carbon and alloy steel. The production of welding fume particles was measured, and the welding fume particles were analyzed by the recommended methods of chemical analysis. These activities were fully carried out according to the standard EN ISO 150011-1. [ABSTRACT FROM AUTHOR]

Within the thermal power plants there are many places where the personnel work in improper conditions. Depending on the concentration and toxicity of gases, duration of exposure for the personnel, the air can have harmful effects. Currently, several specific measures to limit toxic gases have been introduced in the thermal energy system. This paper presents as example the situation in Borzesti thermal power plant, through modern methods of analysis, by identification and monitoring the physical and chemical properties of the toxic gasses. Some specific measures for the protection of employees are presented based on measurements of the composition of the toxic gasses. After identifying the places with a high degree of risk, a technical-organizational solution was developed regarding the improvement of the toxic gas evacuation, including the influence of the financial costs. In this way the air pollution with CO, CO2, NOx, SOx are significantly reduced. Based on the elaborated study, the main technical solutions were presented, adapted to the working conditions in thermal power plants as different insulating and sound-absorbing cabins to reduce the noise level, alveolar ventilation systems, and modern niches lined with anticorrosive materials. By implementing these rules updated and adapted to the concrete working conditions, the conditions in thermal power plants is in line with the requirements imposed by the EU on the energy industry. [ABSTRACT FROM AUTHOR]

Glina Station is a project for the treatment of wastewater from the sewerage of Bucharest. The sewerage of the entire city has always flowed into the Dambovita River. Currently, only partially Stage I is carried out, through which the mechanical treatment of about 60% of the city's wastewater is carried out. The paper presents a solution for biological pretreatment of wastewater to validate the use of ultraviolet waves for biological disinfection but also for the treatment of specific non-synthetic pollutants from water. It is estimated the impact of pollutant emissions on water resources in the area. The effects of the specific measures that water users must apply to achieve the environmental status, modeling emissions of organic substances, priority substances and specific pollutants are identified. Natural background levels in these transported bodies of water (water, sediment and suspended solid materials), priority substances (heavy metals: Cd, Ni, Pb and Hg) and specific non-synthetic pollutants (Ca, Zn, Cu, Cr, phenols, and others) depending on the allowable base values were determined. The technical solution for biological water pretreatment is presented briefly. In the third tank the homogeneous mixture is made. Next, the physical-chemical reactor and the installation for introducing the dosing and preparation reagents until the final water purification are realized. The main advantages of the pre-treatment of wastewater and selection of the most suitable substances are mentioned also. [ABSTRACT FROM AUTHOR]

Lakes on the Black Sea coast are the direct result of soil erosion and marine or hydrographic accumulations, consequence of the specific evolution of the nearby sea basin. They depend on the variations in groundwater levels, rainfall or other hydraulic surface sources. In recent decades, as a result of many small, local earthquakes, some deep currents have appeared. Lakes as origins, are of fluvial-marine estuary, lagoons or artificial. Many of them are tourist attractions, due to the specific microclimate established here. This paper analyses the physical and chemical composition of these lakes, recorded in recent decades, which demonstrate some environmental problems, caused by the human interference or natural conditions. Firstly, the water sources that supply these lakes are analyzed. About 40-50 years ago, many coastal lakes communicated with the sea and their waters were identical or even saltier than those of the Black Sea. Over time, their evolution from hydro-chemical point of view has been modified by the continental water supply due to hydro-technical assessments, precipitation, new deep currents, and the maintenance or interruption of the connection with the sea. For each analyzed lake, the physical and chemical characteristics are presented and causes that led to morphological modifications. Many of them are nature reserves, being located on the flight corridors of migratory birds, becoming protected areas that urgently need measures to restore the ecological balance. Recent modifications affect ecosystems, vegetation and wildlife. These changes are modeled based on the recorded data, estimating possible evolution of their parameters. Finally, some recommendations are made, adapted to each lake, in order to rebalance the ecological environment. [ABSTRACT FROM AUTHOR]

Stormwater presents a significant problem in urban areas, especially in large cities. The intensified formation of impermeable surface leads to suppressing permeable-vegetation areas and, subsequently, substantial changes in the area's hydrological, environmental, and ecological characteristics. By changing the city's spatial structure, there may be an increase in flood peak, volume of runoff, and rising pollution in urban stormwater. As a result of this phenomenon, the aquatic environment can be degraded by changing water bodies' like rivers, lakes, etc. chemical and physical characteristics. Therefore, today more attention to storm water's qualitative parameters from paved surfaces as car parking, roadways, etc. This article focuses on capturing the first flush of stormwater runoff from impervious areas (roadway) during the rainfall events. The selected area of interest was near the Faculty of Civil Engineering campus in Bratislava, STU (Slovak Republic) - roadway Imricha Karvaša. In the chemical analysis were monitored qualitative parameters as reaction pH and organically bound halogens - AOX. The study aims are to compare the qualitative parameters of individual samples and evaluate them with recommendations of the Government of the Slovak Republic No. 269/2010. According to the results, the average value pH was 7.07, and the average concentration of AOX 767.77 μg.l-1. The concentration of AOX extends the limit value, and therefore in the future, it is necessary to propose some measures (infiltration, retention tanks, etc.) to prevent unsuitable rainwater management. [ABSTRACT FROM AUTHOR]

In this paper, the irradiation of glycerol and ethylene glycol by either mixed (neutron-γ) or γ-only (γ) fields at the TRIGA reactor of the Jožef Stefan Institute is described. This is highly relevant to future applications of fission reactor systems to produce useful feedstock derivatives from organic waste, beyond the production of heat and power. Samples of glycerol and ethyl glycol have been exposed to neutron-gamma radiation with fast neutron fluxes ranging from 7.7×1010 to 3×1012 cm−2s−1 and gamma-only irradiation at maximum dose-rates of 492 and 10 kGy hr−1, respectively. A study of the dependence of product yield versus absorbed dose has been conducted, for total dose ranges of 1 to 100 kGy. The products of these exposures have been identified through Gas Chromatography – Mass Spectrometry (GC-MS) techniques. Analysis comparing neutron-gamma irradiated samples of ethylene glycol and glycerol with gamma-irradiated samples shows no detectable qualitative difference between either irradiation type. Although, additional radiolysis products were detected when compared with available literature; ethyl acetate from ethylene glycol and solketal from glycerol. Quantitatively, neutron-gamma irradiation seems to be less effective at producing acetaldehyde from ethylene glycol, compared with gamma-only which can be explained through neutron moderation and consequent heating effects due to the borosilicate vials. [ABSTRACT FROM AUTHOR]