A preliminary investigation into the effect of different storage methods on the keeping quality of smoked Oreochromis niloticus

The study was carried out to asses the nutritional qualities of smoked O. niloticus and to discover the best methods of storage to minimize spoilage and infestation of smoked fish. Result showed that the protein contents in A and D decreased while the protein contents of b and C increased. The lipid content increased only in A while it decreased in B-C and D. The moisture content generally increased over the period of storage and there was an increase in ash content only in C while it decreased in A, B and D. The samples packed in polythene bag suffered about 35% mould infection and a few were attached by rodents with some fouling. Samples packed in jute bag were in good condition but were slightly attached by insect. All samples packed in carton and basket were still in good state but there were insect attack in those packed in carton

Release of Sulfur and Chlorine During Cofiring Rdf and Coal In An Internally Circulating Fluidized Bed

An internally circulating fluidized bed (ICFB) was applied to investigate the behavior of chlorine and sulfur during cofiring RDF and coal. The pollutant emissions in the flue gas were measured by Fourier transform infrared (FTIR) spectrometry (Gasmet DX-3000). In the tests, the concentrations of the species CO, CO2, HCl, and SO2 were measured online. Results indicated when cofiring RDF and char, due to the higher content of chlorine in RDF, the formation of HCl significantly increases. The concentration Of SO2 is relatively low because alkaline metal in the fuel ash can absorb SO2. The concentration of CO emission during firing pure RDF is relatively higher and fluctuates sharply. With the CaO addition, the sulfur absorption by calcium quickly increases, and the desulfuration ratio is bigger than the dechlorination ratio. The chemical equilibrium method is applied to predict the behavior of chlorine. Results show that gaseous HCl emission increases with increasing RDF fraction, and gaseous KCl and NaCl formation might occur.

Optimization of Air Staging In A 1 Mw Tangentially Fired Pulverized Coal Furnace

This paper deals with an experimental study of air staging in a 1 MW (heat input power) tangentially fired pulverized coal furnace. The influences of several variables associated with air staging on NOx reduction efficiency and unburned carbon in fly ash were investigated, and these variables included the air stoichiometric ratio of primary combustion zone (SR1), the locations of over-fire air nozzles along furnace height, and the ratio of coal concentration of the fuel-rich stream to that of the fuel-lean one (RRL) in primary air nozzle. The experimental results indicate that SR1 and RRL have optimum values for NOx reduction, and the two optimum values are 0.85 and 3:1, respectively. NO, reduction efficiency monotonically increases with the increase of OFA nozzle location along furnace height. On the optimized operating conditions of air staging, NOx reduction efficiency can attain 47%. Although air staging can effectively reduce NOx emission, the increase of unburned carbon in fly ash should be noticed. (C) 2008 Elsevier B.V. All rights reserved.

NOx emission and thermal efficiency of a 300 MWe utility boiler retrofitted by air staging

Full-scale experiments were performed on a 300 MWe utility boiler retrofitted with air staging. In order to improve boiler thermal efficiency and to reduce NOx emission, the influencing factors including the overall excessive air ratio, the secondary air distribution pattern, the damper openings of CCOFA and SOFA, and pulverized coal fineness were investigated. Through comprehensive combustion adjustment, NOx emission decreased 182 ppm (NOx reduction efficiency was 44%), and boiler heat efficiency merely decreased 0.21%. After combustion improvement, high efficiency and low NOx emission was achieved in the utility coal-fired boiler retrofitted with air staging, and the unburned carbon in ash can maintain at a desired level where the utilization of fly-ash as byproducts was not influenced.

Growth response, feed conversion rate and cost benefits of hybrid catfish fed maggot meal based diets in outdoor tanks

The growth response, feed conversion ratio and cost benefits of hybrid catfish, Heterobranchus longifilis x Clarias gariepinus fed five maggot meal based diets were evaluated for 56 days in outdoor concrete tanks. Twenty-five fingerlings of the hybrid fish were stocked in ten outdoor concrete tanks of dimension 1.2mx0.13mx0.18m and code MM sub(1)-MM sub(5) in relation to their diet name. Five isonitrogenous and isocaloric maggot meal based diets namely MM sub(1)-0% maggot meal, MM sub(2)-25% maggot meal, MM sub(3)-50% maggot meal, MM sub(4-)75% maggot meal and MM sub(5-) 100% maggot meal were used for the experiment. The higher the proportion of maggot in the meal, the higher the ether extract and crude fiber. No significance difference P>0.05 exists between ash content of the experimental diets. Diet MM sub(2) had the best growth performance and highest MGR with a significant difference P<0.05 with other diets fed fish. No significance differences P>0.05 exists between the growth parameters for diets MM sub(1), MM sub(3), and MM sub(4). A positive correlation (r=1.0) exists (P<0.05, 0.25) between the growth parameters for the different experimental diets. Highest correlation r super(2)=0.9981 exists P<0.05 between MGR within the treatments. However, there no significant (P>0.05) difference in expenditure but there is between the profit indices and incidence of cost between the trials. MM sub(2) has the best yield cost and net profit. Without any reservation, inclusion of maggot based meal diet is recommended as feed of hybrid catfish to 75% inclusion for growth and profit incidence

Dating and characterizing late holocene earthquakes using paleomagnetics

In this thesis I apply paleomagnetic techniques to paleoseismological problems. I investigate the use of secular-variation magnetostratigraphy to date prehistoric earthquakes; I identify liquefaction remanent magnetization (LRM), and I quantify coseismic deformation within a fault zone by measuring the rotation of paleomagnetic vectors.

In Chapter 2 I construct a secular-variation reference curve for southern California. For this curve I measure three new well-constrained paleomagnetic directions: two from the Pallett Creek paleoseismological site at A.D. 1397-1480 and A.D. 1465-1495, and one from Panum Crater at A.D. 1325-1365. To these three directions I add the best nine data points from the Sternberg secular-variation curve, five data points from Champion, and one point from the A.D. 1480 eruption of Mt. St. Helens. I derive the error due to the non-dipole field that is added to these data by the geographical correction to southern California. Combining these yields a secular variation curve for southern California covering the period A.D. 670 to 1910, with the best coverage in the range A.D. 1064 to 1505.

In Chapter 3 I apply this curve to a problem in southern California. Two paleoseismological sites in the Salton trough of southern California have sediments deposited by prehistoric Lake Cahuilla. At the Salt Creek site I sampled sediments from three different lakes, and at the Indio site I sampled sediments from four different lakes. Based upon the coinciding paleomagnetic directions I correlate the oldest lake sampled at Salt Creek with the oldest lake sampled at Indio. Furthermore, the penultimate lake at Indio does not appear to be present at Salt Creek. Using the secular variation curve I can assign the lakes at Salt Creek to broad age ranges of A.D. 800 to 1100, A.D. 1100 to 1300, and A.D. 1300 to 1500. This example demonstrates the large uncertainties in the secular variation curve and the need to construct curves from a limited geographical area.

Chapter 4 demonstrates that seismically induced liquefaction can cause resetting of detrital remanent magnetization and acquisition of a liquefaction remanent magnetization (LRM). I sampled three different liquefaction features, a sandbody formed in the Elsinore fault zone, diapirs from sediments of Mono Lake, and a sandblow in these same sediments. In every case the liquefaction features showed stable magnetization despite substantial physical disruption. In addition, in the case of the sandblow and the sandbody, the intensity of the natural remanent magnetization increased by up to an order of magnitude.

In Chapter 5 I apply paleomagnetics to measuring the tectonic rotations in a 52 meter long transect across the San Andreas fault zone at the Pallett Creek paleoseismological site. This site has presented a significant problem because the brittle long-term average slip-rate across the fault is significantly less than the slip-rate from other nearby sites. I find sections adjacent to the fault with tectonic rotations of up to 30°. If interpreted as block rotations, the non-brittle offset was 14.0+2.8, -2.1 meters in the last three earthquakes and 8.5+1.0, -0.9 meters in the last two. Combined with the brittle offset in these events, the last three events all had about 6 meters of total fault offset, even though the intervals between them were markedly different.

In Appendix 1 I present a detailed description of my standard sampling and demagnetization procedure.

In Appendix 2 I present a detailed discussion of the study at Panum Crater that yielded the well-constrained paleomagnetic direction for use in developing secular variation curve in Chapter 2. In addition, from sampling two distinctly different clast types in a block-and-ash flow deposit from Panum Crater, I find that this flow had a complex emplacement and cooling history. Angular, glassy "lithic" blocks were emplaced at temperatures above 600° C. Some of these had cooled nearly completely, whereas others had cooled only to 450° C, when settling in the flow rotated the blocks slightly. The partially cooled blocks then finished cooling without further settling. Highly vesicular, breadcrusted pumiceous clasts had not yet cooled to 600° C at the time of these rotations, because they show a stable, well clustered, unidirectional magnetic vector.

Optimal guidance of low-thrust interplanetary space vehicles

The low-thrust guidance problem is defined as the minimum terminal variance (MTV) control of a space vehicle subjected to random perturbations of its trajectory. To accomplish this control task, only bounded thrust level and thrust angle deviations are allowed, and these must be calculated based solely on the information gained from noisy, partial observations of the state. In order to establish the validity of various approximations, the problem is first investigated under the idealized conditions of perfect state information and negligible dynamic errors. To check each approximate model, an algorithm is developed to facilitate the computation of the open loop trajectories for the nonlinear bang-bang system. Using the results of this phase in conjunction with the Ornstein-Uhlenbeck process as a model for the random inputs to the system, the MTV guidance problem is reformulated as a stochastic, bang-bang, optimal control problem. Since a complete analytic solution seems to be unattainable, asymptotic solutions are developed by numerical methods. However, it is shown analytically that a Kalman filter in cascade with an appropriate nonlinear MTV controller is an optimal configuration. The resulting system is simulated using the Monte Carlo technique and is compared to other guidance schemes of current interest.

Application of ipil- ipil leaf meal (IILM) as feed Ingredient for Monosex tilapia fry (oreochronis niioticus) : In terms of growth and economics

The Ipil-ipil (Leucaena leucocephal) leaf analyzed for crude protein (CP), fat, crude fibre (CF), ash content, moisture content and nitrogen free extract (NFE). The CP 23± 0.12 % , fat 8 ± 0.11 %, CF 18 ± 0.15 % , ash 10 ± 0.13 %, moisture 14. ± .16% and NFE 29.± 1.10 % were recorded. A twenty one days experiment was conduced to assess the response of juvenile monosex tilapia with different iso-nitrogenous formulated diets for find out the feasibility study of using ipil-ipil leaf meals as feed ingredient for juvenile tilapia. Three experimental diets were formulated by using fish meal, soybean meal, rice bran and ipil ipil leaf meal. One control diet was formulated by using fish meal, soybean meal and rice bran. Considering the high demand, limited availability of fish meal and soybean meal, ipil ipil leaf meal was incorporated in juvenile tilapia feed. Among plant protein ingredients ipil ipil leaf meal was considered as the most nutritive plant protein source after soybean meal. However, high concentration of toxic element limited the incorporation level of ipil ipil leaf meal in fish feed. Use of 15 % ipil ipil leaf meal in fish feed was more significant from the view of growth performance and economics. The higher Absolute Growth was 1119.26 gm, higher Specific Growth Rate was 6.52% /day higher Feed Conversion Efficiency was 41.23% , higher Protein Efficiency Ratio was 1.178 and higher Average Daily Growth rate was 14.00% recorded in diet-4 ( which contained 15% IILM). The lower Feed Conversion Ratio 2.42 and lower cost for per unit production 34.65 taka/kg were recorded in diet-4. The higher cost for per unit fish production 45.6 tk./kg was recorded for diet-1 where no ipil ipil leaf meal.. The results suggest that tree legumes Ipil-ipil (Leucaena leucocephal) leaf has potential and excellent source of feed ingredients as protein supplements for juvenile monosex

Geology of the Pacoima Area, Los Angeles County, California

The Pacoima area is located on an isolated hill in the northeast section of the San Fernando, the northeast portion of the Pacoima Quadrangle, Los Angeles County, California. Within it are exposed more than 2300 feet of Tertiary rocks, which comprise three units of Middle Miocene (?) age, and approximately 950 feet of Jurassic (?) granite basement. The formations are characterized by their mode of occurrence, marine and terrestial origin, diverse lithology, and structural features.

The basement complex is composed of intrusive granite, small masses of granodiorite and a granodiorite gneiss with the development of schistosity in sections. During the long period of erosion of the metamorphics, the granitic rocks were exposed and may have provided clastic constituents for the overlying formations.

As a result of rapid sedimentation in a transitional environment, the Middle Miocene Twin Peaks formation was laid down unconformably on the granite. This formation is essentially a large thinning bed of gray to buff pebble and cobble conglomerate grading to coarse yellow sandstone. The contact of conglomerate and granite is characterized by its faulted and depositional nature.

Beds of extrusive andesite, basalt porphyry, compact vesicular amygdaloidal basalts, andesite breccia, interbedded feldspathic sands and clays of terrestial origin, and mudflow breccia comprise the Pacoima formation which overlies the Twin Peaks formation unconformably. A transgressing shallow sea accompanied settling of the region and initiated deposition of fine clastic sediments.

The marine Topanga (?) formation is composed of brown to gray coarse sandstone grading into interbedded buff sandstones and gray shales. Intrusions of rhyolitedacite and ash beds mark continued but sporatic volcanism during this period.

The area mapped represents an arch in the Tertiary sediments. Forces that produced the uplift of the granite structural high created stresses that were relieved by jointing and faulting. Vertical and horizontal movement along these faults has displaced beds, offset contacts and complicated their structure. Uplift and erosion have exposed the present sequence of beds which dip gently to the northeast. The isolated hill is believed to be in an early stage of maturity.

The Pacoima Area

The Pacoima area consists of Miocene (sediments and basalts) rocks underlain by a quartz diorite basement complex of Jurassic age. The stratigranhic units range from 25 feet to more than 600 feet in thickness. The lower sediments are arkosic land- laid deposits while the Modelo formation, shallow marine in origin, consists of thinly bedded sandstones, shales, volcanic ash and calcareous members. An andesitic mass, possibly a volcanic plug, outcrops near the summit of one of the hills.

An anticline, and possibly an associated syncline, has been developed by compressional folding. Small scale contortion is locally exposed. Regional dip is northward, decreasing from south to north in the area. Faulting is common, most faults trending nearly north-south. Movement along these faults ranges from a few feet to several hundred feet.

There are no important mineral deposits in the area. Quarrying of the basement rocks has been abandoned.

The significance of sedimentation and sediments to phytoplankton growth in drinking-water reservoirs

In the mesotrophic-eutrophic Saidenbach Reservoir in Saxony, the nanoplankton and cyanobacteria have increased at the expense of diatom dominance, due to a doubling of the external phosphorus load in the last 15 years. However, the phosphorus sedimentation flux is still very high (up to 80% of the input), corresponding to more than 2 g m2 d-1 in terms of dry weight. There is a strong correlation between the abundance of diatoms in the euphotic zone and their sedimentation flux (with a delay of about 2 weeks). Only about 25% of the deposited material could be clearly attributed to plankton biomass; the remainder resulted from flocculation and precipitation processes or directly from the inflow of clay minerals. The ash content of the deposited material was high (73%). Thus the sedimentation flux can be considered to operate as an internal water-treatment/oligotrophication process within the lake. The neighbouring Neunzehnhain Reservoir still has a very clear water with a transparency up to 18 m depth. Though the sediment was not much lower than Saidenbach sediment in total phosphorus and total numbers of bacteria, sulphide was always absent and the ratio of Fe 2+ to Fe 3+ was very low in the upper (0- 5 cm) layer. Thus the external and internal phosphorus loads do not attain the critical level necessary to induce a ”phosphorus - phytoplankton” feedback loop.

Comparative evaluation of the proximate composition of smoked and salted-dried Oreochromis niloticus

This study was carried out to evaluate and compare the shelf life of smoked and salted-dried Oreochromis niloticus over a relative time period. Improved traditional smoking kiln and salting were employed respectively. The smoking kiln was constructed with iron metal with a dimension of 120cm x 70cm and consisting of three smoking racks with dimension of 30 x 30cm each. Table salt was used for preservation of some of the specimens. A total of 30 samples weighing 7.1kg were used. Fifteen (15) samples each were used respectively for smoking and salting. Satisfactory smoking was achieved in two days while salting to dryness was accomplished in four days. The initial percentage proximate compositions of the smoked products were 7.94%, 66. 97%, 8.`84% and 2.96% for moisture, protein, lipid and ash respectively, while that of the salted products were 8.37%, 63.93%, 12.91% and 3.95% for moisture, protein, lipid and ash. Preliminary results of the proximate compositions of the two products at the end of the fifth week of storage were as follows; 8.23%, 65.70%, 10.63% and 2.23% for moisture, protein, lipid and ash respectively of the smoked products, while 6.33%, 64.25%, 11.28% and 2.38% represent the values of moisture, protein, lipid and ash of the salted-dried products. By the individual product proximate characterization, it was discovered that both products were still relatively in good and acceptable condition. However, the protein and moisture values of the smoked products were relatively greater than those of the salted-dried products, while on the other hand, lipid and ash were relatively greater in salted-dried products. The prevailed relative higher moisture in the smoked products constitutes a predisposing condition for microbial activity and spoilage of the products, while the relative higher percentage lipid in the salted-dried products predisposes the products to lipid oxidation and rancidity.

Méthodes des mesures des biovolumes, poids secs, poids secs sans cendres et des éléments C, N, P du mésozooplancton utilisées au C.R.O. d'Abidjan

Methods for the estimation of zooplankton biomasses, used in the Oceanographic Research Center of Abidjan are presented. They deal with settled and displacement volumes, dry weight and ash-free dry weight, elementary carbon, nitrogen and phosphorus composition. The dry weight method is detailed: elimination of salt by a fresh water stream, preservation of dry samples at -20 degrees Celsius, rehydration during weighing. A few comments on the 'CHN' analysed values are made: at 1,100 degrees Celsius, most of the carbon is organic, only 10% of the mineral fraction being analysed.

Dix ans de mesures de biomasses de zooplancton a la station cotière d'Abidjan: 1969-1979

Graphs of variations of zooplankton biomasses expressed as ash-free dry weight (i.e. organic matter) are presented for the 1969-1979 period. The graph of the average year shows: an enrichment season from mid-July till mid-November in which the biomass is 2.3 times higher than the rest of the year and characterized by a slight decrease of the biomass in late August or early September. The warm season is divided into a period of moderate biomass from November till February, a period of moderate biomass from November till February and a period of steady decline of the biomass till the start of the upwelling at the end of June.