Digitization of nonautonomous control systems

AbstractMethods of the theory of nonautonomous differential equations are used to study the extent to which the properties of local null controllability and local feedback stabilizability are preserved when a control system with time-varying coefficients is digitized, e.g., approximated by piecewise autonomous systems on small time subintervals

Preliminary study on the antioxidative and antimicrobial effects of fresh garlic (Allium sativum) on the shelf life of hot smoked catfish (Clarias gariepinus)

The effects of fresh garlic (Allium sativum) at concentrations of 0 g/kg (control), 10 g/kg, 30 g/kg and 50 g/kg of fish on lipid oxidation and microbial growth of hot smoked catfish Clarias gariepinus during a 28 day storage period at ambient temperature of 20-260C was examined. The samples were subjected to chemical and microbial analyses during the storage period. The results of analyses suggest that fresh garlic possesses antioxidant and antimicrobial properties, which can extend the shelf life of Clarias gariepinus

Preliminary study on the antioxidative and anti-fungal effects of ginger oil on the shelf life of hot smoked fish

The anti-oxidative and anti-fungal effects of ginger oil on smoked Chrysichthys nigrodigitatus, Clarias gariepinus and Oreochromis niloticus was examined during five week storage at room temperature (25-30)~'C. The ginger oil was extracted from fresh ginger through hydro-distillation. The fish samples were gutted washed thoroughly and each fish species was divided into three groups. Two groups were spiced with 1.0ml and 1.5ml of ginger oil/kg of fish respectively before they were smoke dried for 2 hours. The third group acts as the control which was not spiced with ginger oil. Chemical and microbiological analyses were performed to investigate quality changes, and to determine the shelf stability of the products. The lowest TBA (14.64 mg MDA/kg), and Peroxide (3.91 mEq/kg) values were recorded in 0. niloticus samples treated with 1.5ml ginger oil/kg of fish at week 1, while the highest TBA (30.48 mg MDA/kg), and PV (18.76 mEq/kg) occurred in the C. gariepinus control at week 5. The result also revealed that samples treated with ginger oil had lower mould count than the control, but there was no significant different (P~.0.05), when compared to the control after 5 weeks of storage

Phytoremediation of iron (Fe) and copper (Cu) by water hyacinth (Eichhornia crassipes)

This study was carried out to investigate the ability of Water Hyacinth (Eichhornia crassipes [Mart.]Solms) to absorb and translocate iron (Fe) and copper (Cu). The study was conducted with three concentration gradients of Fe and Cu at 10mg/l, 15mg/l, 20mg/l and control (no metal); the whole set-up was done in triplicates and the experiment lasted for 12 weeks. The results showed that iron (Fr) had the highest accumulation value in the root (1.12 ~c 0.42), while copper (Cu) had the highest value in the leave (0.38 ~c 0.06); both at 20mg/l. Statistical analysis showed that there was significant difference among treatment (p&lt0.05). Translocation factor (TF) is the ratio between metal concentrations in aerial part to metal concentration in the root. Metals that are accumulated by plants and largely stort in the roots are indicated by TF values less than 1, when greater than 1, its indicate good translocation capabilities. The TF value for Fe ranged from 0.49 ~c 0.57- 0.68 ~c 0.27 in leaf, and 0.64 ~c 0.17- 0.77 ~c 0.18 in the stem. While the Translocation factor values for Ca ranged from 0.78 ~c 0.08- 1.12 ~c 0.12 in leaf and 0.72 ~c 0.32- 1.09 ~c 0.19 in the stem. This reveals that Cu had better translocation capability than Fe. Highest values of bioconcentration factor (BCF) for Fe and Cu were 2.32 ~c 0.65 at 20mg/l and 0.72 ~c 0.01 at 15mg/l obtained in the root and leaf respectively, indicating that the accumulation potential of Fe by water hyacinth is higher than Cu. In conclusion, according to the accumulation capabilities of the investigated plant (Eichhornia crassipes), this study showed that the plant was found to be a promising candidate for phytoremediation and adequate for bio-monitoring programs for contaminated water

Comparison of actual and predicted routes used in the shipment of radioactive materials

A number of highway controlled shipments of radioactive materials have been made over the past several years. An excellent example showing the variability of actual routes is the transfer of 45 shipments between the Three Mile Island reactor in Pennsylvania and Scoville, Idaho in 1982 and 1983. Six different routes varying between 2273 and 2483 miles were used. Approximately 75% of these shipments followed a common route which passed through ten Urbanized Areas, defined by the Census Bureau as having a population exceeding 100,000 people. Other routes, while shorter in distance, passed through as many as 14 Urbanized Areas. Routes predicted by the Oak Ridge routing model did not exactly duplicate actual routes used. However, the analysis shows that the routing model does make a good estimate of transportation routes actually chosen by shippers of radioactive materials. In actual practice, a number of factors (weather, road conditions, driver preference, etc.) influence the actual route taken. 5 refs., 1 fig., 1 tab

Feasibility study and design concept for an orbiting ice-penetrating radar sounder to characterize in three-dimensions the Europan ice mantle down to (and including) any ice/ocean interface

This report presents a radar sounding model based on the range of current working hypotheses for the nature of Europa's icy shell.Institute for Geophysic

DOE transporation programs - computerized techniques

One of the major thrusts of the transportation programs at the Oak Ridge National Laboratory has been the development of a number of computerized transportation programs and data bases. The U.S. Department of Energy (DOE) is supporting these efforts through the Transportation Technology Center at Sandia National Laboratories and the Tranportation Operations and Traffic Management (TOTM) organization at DOE Headquarters. Initially this project was centered upon research activities. However, since these tools provide traffic managers and key personnel involved in preshipment planning with a unique resource for ensuring that the movement of radioactive materials can be properly accomplished, additional interest and support is coming from the operational side of DOE. The major accomplishments include the development of two routing models (one for rail shipments and the other for highway shipments), an emergency response assistance program, and two data bases containing pertinent legislative and regulatory information. This paper discusses the mose recent advances in, and additions to, these computerized techniques and provides examples of how they are used

BIODESULF(TM), A Novel Biological Technology for the Removal of H2S From Sour Natural Gas

The state-of-the-art technologies for the removal of sulfur compounds from Sour Natural Gas (SNG) are not cost-effective when scaled down to approximately 2-5 MMSCFD. At the same time, the SNG Production is increasing at 3-6 TCF/Yr and -78 TCF potential reserves are also sour. Assuming only 3% treatment of this potential SNG market is for small volume processing, the potential U.S. Market is worth $0.14 to$0.28 billion. Therefore, the Gas Processing Industry is seeking novel, cost-effective, environmentally compatible and operator friendly technologies applicable to the small volume producers in the range of less than 1 MMSCFD to - 5 MMSCFD. A novel biological process, BIODESTJLFTM (patent pending), developed at ARCTECH removes H{sub 2}S and other sulfur contaminants that make the Natural Gas Sour. The removal is accomplished by utilizing an adapted mixed microbial culture (consortium). A variety of anaerobic microbial consortia from ARCTECH`s Microbial Culture Collection were grown and tested for removal of H{sub 2}S. One of these consortia, termed SS-11 was found to be particularly effective. Utilizing the SS-11 consortium, a process has been developed on a laboratory-scale to remove sulfur species from Sour Natural Gas at well head production pressures and temperatures. The process has been independently evaluated and found to be promising in effectively removing H{sub 2}S and other sulfur species cost effectively

Haemophilus influenzae type b reemergence after combination immunization

An increase in Haemophilus influenzae type b (Hib) in British children has been linked to the widespread use of a diphtheria/tetanus/acellular pertussis combination vaccine (DTaP-Hib). We measured anti-polyribosyl-ribitol phos- phate antibody concentration and avidity before and after a Hib booster in 176 children 2–4 years of age who had received 3 doses of DTP-Hib (either DT whole cell pertus- sis-Hib or DTaP-Hib) combination vaccine in infancy. We also measured pharyngeal carriage of Hib. Antibody con- centrations before and avidity indices after vaccination were low (geometric mean concentration 0.46μg/mL, 95% confidence interval [CI] 0.36–0.58; geometric mean avidity index 0.16, 95% CI 0.14–0.18) and inversely related to the number of previous doses of DTaP-Hib (p = 0.02 and p<0.001, respectively). Hib was found in 2.1% (95% CI 0.7%–6.0%) of study participants. Our data support an association between DTaP-Hib vaccine combinations and clinical Hib disease through an effect on antibody concen- tration and avidit