Prevention of thromboembolic disease in gynecologic surgery

We presented two groups of patients gynecologically operated and examined in a five year period; the first group of 11536 patients was under thromboembolic protection, whereas the second group of 8532 patients was without thromboembolic protection. Protective measures concerning thromboembolic disease were carried out by applying elastic stockings 24 hours before operation and by early post-operative getting up from bed. Low-molecular dextran was applied before operation as well as during the operation in the amount of 500-1000 ml. In risky patients with varicosities, recidive thrombophlebitis and cardiovascular diseases, we applied small doses of heparin subcutaneously two hours before the operation and after the operation every eight hours five days long. With such prevention of thromboembolic disease in gynecologic surgery, we achieved very favorable effects in reducing mortality to 0.05% concerning the operated, while it amounts to 0.3% in those who were without this kind of protection.     

Chemistry of tap water in Sri Lanka‐implications on health

A preliminary survey on the chemical quality of tap water in Sri Lanka has been carried out and has been grouped into three categories depending on the source of the water. It was revealed that in certain parts of Sri Lanka, the tap water does contain excess quantities of lead. The Piper trilinear diagram shows that much of the tap water of Sri Lanka belongs to the Ca#shMg‐HCO₃ type. Low pH values have also been observed in certain areas and could bring out excess dissolved ions into the tap water. In view of the fact, that only a small percentage of the population of Sri Lanka have access to piped water, no serious health hazards due to the poor quality of the tap water have been encountered.     

Arsenic binding mechanisms on natural red earth: a potential substrate for pollution control

Natural red earth (hereafter NRE) was used as a novel adsorbent to examine its retention behaviour in different inorganic arsenic species (As (III) and As (V)) that are abundant in natural water. Adsorption isotherms were constructed at pH approximately 5.5 for As(III) and As(V) in 0.01 M NaNO(3) at 298K for 5 g/L NRE system. The initial arsenic [As(III) or As(V)] concentrations varied between approximately 10(-5) and approximately 10(-4) M. The experimental data were quantified using single site or stepwise Langmuir models. Sorption maximum, was observed at approximately 0.173 mM of As(V). To reach the maximum surface coverage of red earth at pH approximately 5.5 As(III) requires approximately 0.308 mM of initial loading. When compared to As (III), As(V) shows strong affinity for NRE surface sites. This study suggests the potential of NRE as a starting material in decontaminating water polluted with As species.     

Methyl ester propoxylates

Insertion of propylene oxide into methyl esters is accomplished using a proprietary alkoxylation catalyst. The alkoxylation mechanism is believed to involve transesterification between the alkoxylated metal-alkoxide of the catalyst and the ester. Optimal alkoxylation conditions are discussed. The effect of inserting propylene oxide prior to ethoxylation on surface properties and foam performance is examined. Presented at the annual meeting of the American Oil Chemists' Society, Seattle, WA, May 1997.     

Mineral‐induced degradation of halogentated organic pollutants from aquatic systems

Several laboratory tests were conducted to examine Fe(II) as an enhancing agent in the dehalogenation of CHC1₃ in batch mode. The CHC1₃ degradation was found to be negligible when only Fe(II) is present as a reductant in the (aqueous) reaction system. However, in the presence of Fe(II) coated goethite, the rate of CHC1₃ degradation was enhanced to some extent. This observation can be explained by considering a surface mediated electron transfer step in the overall process. Substantial increase of the degradation rate was observed when the goethite particles first coated with fulvic acid were employed in the adsorption of Fe(II) for the degradation of CHC1₃.     

Impact of molecular structure on the performance of methyl ester ethoxylates

Methyl ester ethoxylates are a new class of ethylene oxide (EO)-derived surfactants. Little is known about the impact of structural variations on their performance properties. The effects of carbon chain length, EO content, the degree of unsaturation of the methyl ester feedstock, and feedstock purity were examined for their impact on both physical properties and surfactant performance properties. Physical properties examined included surface properties (surface tension, critical micelle concentration, surface excess adsorption), melting point, water solubility, viscosity, foam stability, color, clarity, and odor. The impact of molecular structure on performance was examined for various applications, including laundry detergents, dishwashing detergents, and hard-surface cleaners. Presented at the AOCS Annual Meeting & Expo, May 1997, Seattle, Washington.     

Identification of Effective Management Practices and Technologies for Lessons Learned Programs in the Construction Industry

Organizations in the construction industry cannot afford to make repetitive mistakes on major projects. Conversely, there are great benefits to repeating positive experiences from past projects. This need for institutional memory is amplified by the reality that in the course of normal turnover and retirement, people with years of experience leave their organizations. An effective lessons learned program is a critical element in the management of institutional knowledge; it will facilitate the continuous improvement of processes and procedures and provide a direct advantage in an even more competitive industry. This paper describes a research study that aimed to identify effective management practices and technologies for lessons learned programs in the construction industry. Data from 70 organizations that participated in this study are presented. Research found that even though more lessons learned programs are being initiated, the potential for savings and improvement has not been fully met. The study has also identified seven crucial characteristics of a successful program and verified that most organizations are stronger in some categories and weaker in others. The key to an effective program is to address all seven areas and guidance is provided for those wishing to implement lessons learned programs.     

Laboratory implementation of a neural network trajectory controllerfor a DC motor

The laboratory implementation of a neural network controller for high performance DC drives is described. The objective is to control the rotor speed and/or position to follow an arbitrarily selected trajectory at all times. The control strategy is based on indirect model reference adaptive control (MRAC). The motor characteristics are explicitly identified through a multilayer perceptron type neural network. The output of the trained neural network is used to drive the motor in order to achieve a desired time trajectory of the controlled variable. The neural network controller is assembled in a commercially available PC-based real-time control system shell, using software subroutines. An H-bridge, DC/DC voltage converter is interfaced with the computer to generate the specified terminal voltage sequences for driving the motor. All software and hardware components are off the shelf. The versatility of the motor/controller arrangement is displayed through real-time plots of the controlled states     

Geochemistry of well water and cardiovascular diseases in Sri Lanka

A survey carried out on the incidence of cardiovascular diseases in Sri Lanka in relation to the hardness of drinking water reveals that a correlation exists which is geographically related. This correlation however, cannot be considered as a causal relationship and other factors possibly exist that could also play a major role in the incidence of cardiovascular diseases, e.g. trace elements.     

Ester alkoxylation technology

Conventional ethyoxylation technologies, when used on fatty methyl esters, produce poor yields as well as flat ethoxymer distributions. Peaking ethoxylation catalysts have been successful in efficient conversion of methyl esters into the ethoxylates possessing peaked ethoxymer distribution. Surfactant performance of methyl ester ethoxylates was evaluated. Results generally show these to behave similarly to alcohol ethoxylates, with the exception of exhibiting a lower foam profile. This ester ethoxylation technology has been successful in ethoxylating esters of varying steric environments. Triglyceride ethoxylates have been partially saponified as well as glucaminolyzed to produce mild surfactant blends. Samuel Rosen Memorial Award Presentation, at the 90^th American Oil Chemists' Society Annual Meeting and Expo, Orlando, FL, May 1999. The author dedicates this paper to the memory of the late Professor William H. Wade of the University of Texas, Austin, TX.