Differences In Specific Gravity Research Articles

Inter‐ and intraspecific variation in mangrove carbon fraction and wood specific gravity in Gazi Bay, Kenya

AbstractThe tropical mangrove ecosystem harbors great potential for carbon offsetting schemes because of their exceptionally high carbon sequestration potential. These cannot only generate an income for local communities by financially compensating for the non‐exploitation of protected or replanted stands, but also simultaneously reduce emissions due to forest degradation and deforestation, thereby helping to counteract the global threat on these forests. As carbon is directly monetized through offsetting carbon emissions, accurate species‐specific estimation of carbon content in trees is essential and reduces the propagation of errors generated by accounting uncertainties. Accordingly, this study assessed variation in both carbon fraction and wood specific gravity among and within the 10 mangrove species occurring in Gazi Bay, Kenya. Significant interspecific differences were found with values ranging from 45.8% (Avicennia marina) to 49.8% (Ceriops tagal) for carbon fraction and from 0.58 (Sonneratia alba) to 0.93 (Pemphis acidula) for wood specific gravity. The influence of environmental factors (soil salinity, stand density, and elevation a.s.l. as a proxy for multiple interrelated conditions) was investigated, but only elevation a.s.l. appeared to have a species‐specific though moderate influence only on carbon fraction. Significant differences in carbon fraction and wood specific gravity were found between stem, aerial roots, and branches of Rhizophora mucronata. In contrast, no significant differences in carbon fraction were found among different stem tissues of A. marina, C. tagal and R. mucronata, the Bay's most abundant species. These results provide insight in carbon content variation, confirming the importance of considering species‐specific or even site‐specific values of carbon fraction and wood specific gravity, thereby rendering future carbon accounting more accurate.

In-plant production of bricks containing waste foundry sand—A study with Belgaum foundry industry

The main objective of this study is to utilize waste foundry sand (WFS) from Belgaum foundry industry in manufacturing of bricks. The process involved production of bricks in a fully functioning brick manufacturing plant, which has a production capacity of approximately 50000 bricks per month. The entire process of combining clay-sand mixtures, forming of bricks, drying and firing was done with local conditions. With minimum process it was possible to introduce upto 50% WFS in clay bodies to produce bricks of desirable properties. The minimum average wet compression resistance of 3.3 Mpa, and maximum average water absorption of 21.6% was obtained for bricks containing 50% WFS, when fired at 900 °C. There was insignificant difference in apparent porosity, water absorption, and specific gravity of bricks containing WFS, when compared to commercial bricks. The addition of WFS reduced the bulk density of the bricks, which has also caused reduction in compressive strength. WFS bricks can be classified as class III bricks, based on recommendations of IS 1077 standard specification. These bricks can be used in single storied load bearing structures, and also in the construction of infill walls in multi-storied framed structures. The structure, composition, and morphology of the raw materials, as well as bricks were studied by XRD, XPS, and SEM, respectively.

VARATION OF RINGS WIDTH AND LTS EFFECT ON WOOD SPECIFIC GRAVITY OF Pinus brutia TEN. AND Cupressus sempervirens VAR. Pyramidalis TOZZ. TREES GROWN IN NINAVAH PLANTATION

Four trees growing in Ninavah plantation were chosen, two of them are Pinus brutiaTen.and the others are Cupressus sempervirens var. pyramidalis Tozz.. The trees were filled, from each tree six sample discs of (25 mm) thick were taken, three of them directly above (1.3m) and the others below, then each disc were radially sawn in the four directions of the radius, the test specimens were cut from these with the dimensions of (25 × 25 × 25 mm) used for measuring annual ring width and wood specific gravity. A significant difference in ring width and wood specific gravity was observed along the radial axis from pith to bark, the value of ring width decreases while wood specific gravity increase, and significant negative relationships had been found between ring width and wood specific gravity in both pine and cypress. There were significant difference between the trees. The mean value of ring width was (3.951mm) for pine while it was (3.141mm) for cypress, and the mean wood specific gravity of pine was (0.556) while it was (0.505) for cypress.

Study on Sumbawa gold recovery using centrifuge

The Artisanal Small Gold Mining in Sumbawa has been processing gold with mercury (Hg), which poses a serious threat to the mining and global environment. One method of gold processing that does not use mercury is by gravity method. Before processing the ore first performed an analysis of Mineragraphy and analysis of compound with XRD. Mineragraphy results show that gold is associated with chalcopyrite and covelite and is a single particle (native) on size 58.8 μm, 117 μm up to 294 μm. characterization with XRD shows that the Sumbawa Gold Ore is composed of quartz, pyrite, pyroxene, and sericite compounds. Sentrifugation is one of separation equipment of gravity method to increase concentrate based on difference of specific gravity. The optimum concentration result is influenced by several variables, such as water flow rate and particle size. In this present research, the range of flow rate is 5 lpm and 10 lpm, the particle size - 100 + 200 mesh and -200 +300 mesh. Gold concentration in concentrate is measured by EDX. The result shows that the optimum condition is obtained at a separation with flow rate 5 lpm and a particle size of -100 + 200 mesh.

Development of strong lightweight cementitious matrix for lightweight concrete simply by increasing a water-to-binder ratio in Ca(OH)2-Na2CO3-activated fly ash system

Reducing the specific gravity (SG) of structural binder pastes is one possible way to prevent material segregation between binder paste and lightweight aggregates, which often occurs in producing lightweight concrete due to their SG differences. To this end, this study suggests the use of a new lightweight fly ash binder paste, given that its SG can largely be reduced simply by increasing the water-to-binder (w/b) ratio without both excessive bleeding and significant strength reduction. Class F fly ash was activated with varying weights of water (i.e., w/b), Ca(OH)2, and Na2CO3 to prepare the samples. Compressive strength, SG, and water absorption were measured with microstructural study using XRD, TG, and MIP. The results showed satisfactory performances with strengths of 27.8–56.5MPa, an oven-dried SG of 1.24–1.47, and water absorption of 13.3–24wt% for selected representative mixtures at 28days. In particular, the strongest sample, at 56.5MPa, also obtained a low value of oven-dried SG of 1.47, which lay within the range of oven dried SG (∼ 0.6–1.5) of commercial lightweight aggregates. In this study, strength, SG, water absorption, reaction products, and pore characteristics were mainly determined by w/b ratio rather than Ca(OH)2 and Na2CO3 contents; thus, this binder would be more advantageous for quality control than other types of fly ash-based cementless binders in structural construction.

Comparison of Surti goat milk with cow and buffalo milk for physicochemical characteristics, selected processing-related parameters and activity of selected enzymes

Aim:The study was undertaken to find out the physicochemical characteristics, selected processing-related parameters and activity of selected enzymes in Surti goat milk.Materials and Methods:Milk samples from Surti goats and buffalo milk samples were collected during the period from July 2013 to January 2014 at Reproductive Biology Research Unit, Anand Agricultural University (AAU), Anand. Milk samples from Kankrej cows were collected from Livestock Research Station, AAU, Anand. Samples were analyzed for physicochemical characteristics such as acidity, viscosity, surface tension, specific gravity, refractive index, freezing point, and electrical conductivity. Samples were also analyzed for selected processing-related parameters such as heat coagulation time (HCT), rennet coagulation time (RCT), rate of acid production by starter culture, alcohol stability, and activity of selected enzymes such as alkaline phosphatase activity, catalase activity, proteolytic activity, and lipase activity.Results:Goat milk had the highest acidity, viscosity and surface tension, followed by cow milk and buffalo milk. However, the differences in acidity, specific gravity, surface tension, refractive index, electrical conductivity, HCT and lipase activity of three types of milk studied, viz., goat, cow, and buffalo milk were found statistically non-significant (p<0.05). The buffalo milk had the highest specific gravity, followed by those found in cow and goat milk. The viscosity, freezing point and RCT of goat milk was significantly lower (p>0.05) than that of the buffalo milk. However, the difference in viscosity, freezing point and RCT of goat milk and that of the cow milk was statistically non-significant. The cow milk had the highest refractive index, followed by goat and buffalo milk. The cow milk had the highest proteolytic activity and heat coagulation time (HCT), followed by those found in buffalo and goat milk. The goat milk had the lowest freezing point, lipase activity, and RCT, followed by those found in cow and buffalo milk. The goat milk had the highest electrical conductivity, followed by those found in buffalo and cow milk. The collected goat, cow and buffalo milk samples showed negative stability at 68% (v/v) alcohol concentration. Goat milk showed positive alcohol test at 75% (v/v) alcohol concentration. Acidity was found to increase proportionally with time. After 14 h, it was found that goat milk became thicker, but the curd had a very low consistency. Cow milk had the highest alkaline phosphatase activity and catalase activity followed by those found in goat milk and lowest alkaline phosphatase activity and catalase activity was found in buffalo milk. The alkaline phosphatase activity and proteolytic activity of goat milk was significantly lower (p>0.05) than that of the cow milk. However, the difference in alkaline phosphatase activity and proteolytic activity of goat milk and that of the buffalo milk was statistically non-significant. Alkaline phosphatase activity of buffalo milk was significantly lower (p>0.05) than that of the alkaline phosphatase activity in cow milk.Conclusion:It can be concluded from the study that the goat milk has highest acidity, viscosity, electrical conductivity, and surface tension compared to that of cow and buffalo milk. The goat milk has lowest specific gravity, freezing point, proteolytic activity, lipase activity, RCT and HCT compared to cow and buffalo milk. Goat milk had highest refractive index compared to buffalo milk, whereas lowest refractive index compared to cow milk. Goat milk showed positive alcohol test at 75% (v/v) alcohol concentration. The curd formed from goat milk after 14 h was having very weak consistency. The goat milk has higher alkaline phosphatase activity, catalase activity compared to buffalo milk while it has lower alkaline phosphatase activity, catalase activity compared to cow milk.

Egg buoyancy of flounder, Platichthys flesus, in the Baltic Sea—adaptation to salinity and implications for egg survival

Vertical distribution of eggs as determined by the egg buoyancy, i.e. the difference in specific gravity between the egg and the ambient water, have profound implications for the reproductive success and hence recruitment in fish. Here variability in egg specific gravity of flounder, Platichthys flesus, was studied along a salinity gradient and by comparing two reproductive strategies, spawning pelagic or demersal eggs. Egg characteristics of 209 egg batches (covering ICES subdivisions (SD) 22–29 in the brackish water Baltic Sea) was used to reveal the significance of egg diameter and egg dry weight for egg specific gravity (ESG), subpopulations, and egg survival probabilities of pelagic eggs following a major saline water inflow event. As an adaptation to salinity, ESG (at 7°C) differed (p<0.001) between areas; three subpopulations of flounder with pelagic eggs: 1.0152±0.0021 (mean±sd)gcm−3 in SD 22, 1.0116±0.0013gcm−3 in SD 24 and 25, and 1.0096±0.0007gcm−3 in SD 26 and 28, contrasting to flounder with demersal eggs, 1.0161±0.0008gcm−3. Egg diameter differed (p<0.001) between subpopulations; from 1.08±0.06mm (SD 22) to 1.26±0.06mm (SD 26 and 28) for pelagic eggs and 1.02±0.04mm for demersal eggs, whereas egg dry weight was similar; 37.9±5.0μg (SD 22) and 37.2±3.9μg (SD 28) for pelagic, and 36.5±6.5μg for demersal eggs. Both egg diameter and egg dry weight were identified as explanatory variables, explaining 87% of the variation in ESG. ESG changed during ontogeny; a slight decrease initially but an increase prior to hatching. Egg survival probabilities judged by combining ESG and hydrographic data suggested higher egg survival in SD 25 (26 vs 100%) and SD 26 (32 vs 99%) but not in SD 28 (0 and 3%) after the inflow event, i.e. highly fluctuating habitat suitability. The results confirm the significance of ESG for egg survival and show that variability in ESG as and adaptation to salinity is determined mainly by water content manifested as differences in egg diameter; increase in diameter with decreasing salinity for pelagic eggs, and decreased diameter resulting in demersal eggs.

Design of a ferrochrome – slag mechanical separator case study

This research focused on the design of a ferrochrome – slag mechanical separator for a company in Harare, Zimbabwe. The company’s current production is 420 tonnes of alloy per month. The aim of project is to raise the production from 420 to 500 tonnes of ferrochrome production per month by introducing a mechanical separator at metal recovery plant that produces 80 tonnes. The difference in specific gravities of ferrochrome and slag is the key principle applied in achieving separation of the two products. The densities of ferrochrome and slag are 6800 kg/ m 3 and 2800kg/ m 3 respectively hence gravity separation method in water medium can be done.

Regional Variation in Juice Quality Characteristics of Four Cider Apple (Malus ×domestica Borkh.) Cultivars in Northwest and Central Washington

In this study, four cider apple (Malus ×domestica) cultivars, Brown Snout, Dabinett, Kingston Black, and Yarlington Mill, were collected from four orchards, two in northwest Washington and two in central Washington, to compare juice quality characteristics. Northwest Washington has a cool, humid summer climate (16.0 °C on average during this study) and is the origin of the state’s cider apple industry, while central Washington has a hot, dry summer climate (22.1 °C on average during this study) and is the center of the state’s dessert apple industry. Each year from 2012 to 2015, fruit of the four cultivars were harvested and stored at each orchard until they were collected. Fruit were pressed and the juice analyzed for five quality characteristics important to cider making: soluble solids concentration [SSC (%)], specific gravity (SG), pH, titratable acidity [TA, malic acid equivalent (g·L−1)], and tannin [tannic acid equivalent (%)]. Harvest dates and climate data were recorded annually for each orchard location. There were no significant differences in any of the juice quality characteristics due to region and no significant interaction of region, cultivar, and/or year. Results did show, as expected, a significant difference in all five juice characteristics due to cultivar. ‘Brown Snout’, ‘Dabinett’, and ‘Kingston Black’ were higher in SSC and SG than ‘Yarlington Mill’; ‘Dabinett’ had the highest pH and lowest TA while ‘Kingston Black’ had the lowest pH and highest TA; and tannin was highest in ‘Yarlington Mill’ and lowest in ‘Kingston Black’. There was also a difference in SG and tannin due to year; SG was lowest in 2013 while tannin was highest in 2012. The difference in SG from year to year may be a result of variable year-to-year storage time at each orchard before collection of fruit. The difference in tannin from year to year was likely due to climatic variation over the four years of this study. On average, growing degree days (GDD) increased 10% and chilling hours (CH) decreased 10% from 2012 to 2015 in both regions. Classification of the four cultivars included in this study differed from historical records at the Long Ashton Research Station (LARS) in England; in the current study, the four cultivars exhibited tannin levels below 0.20% and would not be classified as bitter, unlike their historical classification at LARS. Results from this study indicate that variations in juice quality characteristics occur between cultivars as expected and occur within a cultivar from year-to-year, but for the four cultivars included in this study variations did not occur due to production region in Washington.

Chipping ability, specific gravity and resistance to Pectobacterium carotovorum in advanced potato selections

ABSTRACTThe availability of potato varieties combining good tuber quality and resistance traits is very important for both processors and supermarkets. In the present study, post-harvest quality traits as well as resistance to tuber bacterial soft rot were evaluated in 42 advanced potato clones belonging to seven hybrid families. Differences in specific gravity were found among families and among clones, with about 30% of clones showing a high specific gravity (>1.080). Clones and varieties were assayed also for a comprehensive chipping profile. Overall, 43% of clones presented an acceptable chipping score (≤4.5) at harvest. In addition, following cold storage with and without reconditioning, various clones performed acceptably. Five clones from three families (Bolestra X MC 329, Spunta X Victoria and Majestic X Alcmaria) were classified as resistant to bacterial soft rot. An evaluation index is proposed to help identify clones with interesting combinations of traits.

Effects of aging on the function of the urinary system: longitudinal changes with age in selected urine parameters in a hospitalized population of older adults

Although normal aging does not have a pernicious effect on the homeostasis of fluids, renal reserve in elderly people can be depleted. The purpose of the present study was to assess the relationship between longitudinal changes with age in basic urine parameters (specific gravity and pH) in older men and women, depending on their body height and relative body weight. Longitudinal data on these two quantitative traits of the urine were available for 142 physically healthy individuals, including 68 men and 74 women. All subjects were 45 years of age at the beginning and 70 at the end of the period under investigation. All measurements were taken in accordance with internationally accepted requirements. Specific gravity was assessed using a hydrometer, and pH was measured using a pH meter. ANOVA, t-test, and regression analysis were performed. No significant sex differences in specific gravity or urine pH were observed. In both sexes, urine specific gravity decreased with age according to exponential model of regression. In men, there was a gradual increase in the pH of the urine until age 65, and the best fitting regression model was polynomial. In women, on the other hand, there was an exiguous decrease in urine pH throughout the period under study, and the best fitting regression model proved to be exponential. As the process of renal aging commences relatively early in ontogeny and manifests itself in many structural and functional changes, urinalysis and other more sophisticated methods of diagnosis of renal diseases are essential for proper assessment of health status of adults and older individuals. The rate of age-related changes in the analyzed traits of the urine was commensurate in both sexes, thereby revealing no evidence of significant sex differences in terms of renal aging in the period between 45 and 70 years of age.

Evaluation on Recovery of Glass and Plastics from Compact Fluorescent Lamps (CFLs) by Air Separation Unit

Compact Fluorescent Lamps (CFLs) are composed of glass, plastic, non-ferrous metal, ferrous metal, paper, plastic, rubber, and so on. In order to separate glass and plastic among CFLs components, air separation unit is applied using the difference in specific gravity. Since specific gravities of glass, plastic, non-ferrous metals, rubber, etc. were widely spread, it can be separated by the different specific gravity between 0.40 and 4.36. In air separation unit, particle size and air speed are controlled to recover glass and plastics among the components of CFLs. In other words, it can be removed paper and vinyl to recover glass and plastics. The specific gravities of paper and vinyl in CFLs are 0.45 and 0.88, respectively. And the specific gravities of glass and plastics are almost similar to be 2.2-2.6. In air separation unit, the used particle size of the components from CFLs is less than 6 mm. Since phosphor powder and ferrous metals are recovered prior to the air separation unit, the components are not involved those materials. By utilizing a vertical and zigzag type of air separation unit, thereafter, recovery of glass and plastics is estimated with changing air speed. As the air speed increased from 3.08 m/s to 6.75 m/s, separation efficiency of glass and plastics increased from 42.0% to 99.3%. Due to the experimental results of air separation unit, it can find that paper and vinyl from the components of CFLs be efficiently removed by the air separation unit.

Size, permeability and buoyancy of anchovy (Engraulis Encrasicolus) and sardine (Sardina Pilchardus) eggs in relation to their physical environment in the Bay of Biscay

AbstractThe size and specific gravity of eggs of marine pelagic fish partly determine their dispersal and survival. Using an original dataset of anchovy and sardine eggs, sampled in spring over the last decade in the Bay of Biscay, we provide a parameterization of these properties on ambient water temperature and salinity. We used the density gradient column for measurement of egg specific gravity. The column was also filled with homogeneous water for sinking velocity experiments. For anchovy, these experiments confirm that the effect of egg permeability through the chorion could be neglected when modelling sinking, while it has to be considered for sardine, its perivitelline space representing 78.6% (±6.2%) of the total egg volume, as opposed to 5–10% for most teleosts species. We estimated a coefficient of permeability of the chorion of 0.0038 mm s−1. However, permeability should not affect the measurement of sardine egg specific gravity in a gradient column, provided a minimum duration before reading is respected for equilibrium to be reached. In relation to their environment, we found that the egg specific gravity is largely determined by sea surface salinity for both species, whereas egg size is weakly but significantly impacted by temperature, for sardine only. On average, the estimated difference in specific gravity between egg and surface water is −0.92 σT for anchovy and −1.06 σT for sardine. The detailed parameterization of the relationship between eggs and water properties should prove useful, in particular to modellers dealing with the dispersal of fish early life stages.

Splitting Strength of Mortise Members in Timber Frame Joints

AbstractSplitting resistance of mortise members loaded perpendicular to grain in pegged mortise and tenon joints is an important property in the design of timber frame joints. This paper investigated the effect of loaded edge distance and wood species upon the strength of mortise members loaded perpendicular to grain. To prevent failure of the tenon or pegs, a steel tenon and Grade 8 bolts were substituted. Load and stiffness values from experimental results were significantly different for the factors of loaded edge distance and specific gravity. Perpendicular-to-grain splitting resistance from CSA 086 predicted values were equivalent to the lower specific gravity wood values tested. The Canadian design literature did not account for differences in specific gravity due to different wood species, particularly white oak which is commonly used in timber framing. Comparison of the mortise testing to previous mortise and tenon joint testing showed similar maximum load and stiffness performance.

Enhancement of the Life of Refractories through the Operational Experience of Plasma Torch Melter

The properties of wastes for melting need to be considered to minimize the maintenance of refractory and to discharge the molten slags smoothly from a plasma torch melter. When the nonflammable wastes from nuclear facilities such as concrete debris, glass, sand, etc., are melted, they become acid slags with low basicity since the chemical composition has much more acid oxides than basic oxides. A molten slag does not have good characteristics of discharge and is mainly responsible for the refractory erosion due to its low liquidity. In case of a stationary plasma torch melter with a slant tapping port on the wall, a fixed amount of molten slags remains inside of tapping hole as well as the melter inside after tapping out. Nonmetallic slags keep the temperature higher than melting point of metal because metallic slags located on the bottom of melter by specific gravity difference are simultaneously melted when dual mode plasma torch operates in transferred mode. In order to minimize the refractory erosion, the compatible refractories are selected considering the temperature inside the melter and the melting behavior of slags whether to contact or noncontact with molten slags. An acidic refractory shall not be installed in adjacent to a basic refractory for the resistibility against corrosion.

Growth of BaTiO3-PVDF composite thick films by using aerosol deposition

Barium titanate (BaTiO3)-polyvinylidene fluoride (PVDF) composite thick films were grown by using aerosol deposition at room temperature with BaTiO3 and PVDF powders. To produce a uniform composition in ceramic and polymer composite films, which show a substantial difference in specific gravity, we used PVDF-coated BaTiO3 powders as the starting materials. An examination of the microstructure confirmed that the BaTiO3 were well distributed in the PVDF matrix in the form of a 0 – 3 compound. The crystallite size in the BaTiO3-PVDF composite thick films was 5 ∼ 50 times higher than that in pure BaTiO3 thick films. PVDF plays a role in suppressing the fragmentation of BaTiO3 powder during the aerosol deposition process and in controlling the relative permittivity.

Segregation of corky tissue affected fruits of sapota by specific gravity method

Sapota cv. Cricket Ball is a popular commercial variety in India which is plagued by the physiological disorder known as Corky Tissue (CT). This disorder adversely affects the eating quality of the fruit, making it unfit for consumption. This paper describes a technique of dipping sapota fruits in 12.5% salt solutions to segregate the CT affected fruits from healthy fruits based on differences in fruit specific gravity. The healthy fruits with a specific gravity of >1.0895 sank to the bottom, while the fruits affected by CT having a specific gravity of <1.0895 floated on the solution, thus ensuring complete separation of healthy and CT fruits in a single step process. The method is simple, rapid and cost effective and could be applied for culling out CT affected fruits at the field level by the growers and traders.

The Principles of Buoyancy in Marine Fish Eggs and Their Vertical Distributions across the World Oceans.

Buoyancy acting on plankton, i.e. the difference in specific gravity between plankton and the ambient water, is a function of salinity and temperature. From specific gravity measurements of marine fish eggs salinity appears to be the only determinant of the buoyancy indicating that the thermal expansions of the fish egg and the ambient seawater are equal. We analyze the mechanisms behind thermal expansion in fish eggs in order to determine to what extent it can be justified to neglect the effects of temperature on buoyancy. Our results confirm the earlier assumptions that salinity is the basic determinant on buoyancy in marine fish eggs that, in turn, influence the vertical distributions and, consequently, the dispersal of fish eggs from the spawning areas. Fish populations have adapted accordingly by producing egg specific gravities that tune the egg buoyancy to create specific vertical distributions for each local population. A wide variety of buoyancy adaptations are found among fish populations. The ambient physical conditions at the spawning sites form a basic constraint for adaptation. In coastal regions where salinity increases with depth, and where the major fraction of the fish stocks spawns, pelagic and mesopelagic egg distributions dominate. However, in the larger part of worlds’ oceans salinity decreases with depth resulting in different egg distributions. Here, the principles of vertical distributions of fish eggs in the world oceans are presented in an overarching framework presenting the basic differences between regions, mainly coastal, where salinity increases with depth and the major part of the world oceans where salinity decreases with depth. We show that under these latter conditions, steady-state vertical distribution of mesopelagic fish eggs cannot exist as it does in most coastal regions. In fact, a critical spawning depth must exist where spawning below this depth threshold results in eggs sinking out of the water column and become lost for recruitment to the population. An example of adaptation to such conditions is Cape hake spawning above the critical layer in the Northern Benguela upwelling ecosystem. The eggs rise slowly in the onshore subsurface current below the Ekman layer, hence being advected inshore where the hatched larvae concentrate with optimal feeding conditions.

Comparison of Loblolly, Shortleaf, and Pitch X Loblolly Pine Plantations Growing in Oklahoma

We measured survival, growth, stem volume, bark thickness, crown area, and stem specific gravity of 10-year-old loblolly pine (Pinus taeda L.), shortleaf pine (P. echinata Mill.), and pitch X loblolly pine hybrid (P. rigida Mill. X P. taeda L.) stands planted at four sites in southeastern Oklahoma to determine the best species for expanding the commercial pine range. Loblolly pine and the pitch X loblolly pine hybrid plantations had greater survival (70%) than shortleaf pine (59%). After 10 growing seasons, loblolly pine reached an average height of 9.4 m and dbh of 16.5 cm, outgrowing both the pitch X loblolly pine hybrids (8.3 m and 14.2 cm height and dbh, respectively) and shortleaf pine (6.8 m and 11.8 cm, height and dbh, respectively). We did not observe any statistical differences in stemwood specific gravity among the pine species when measured near ground level (overall mean of 0.50). Although crown area and bark thickness increased with tree size, loblolly, shortleaf, and pitch X loblolly pine did not differ when compared at the same dbh. We conclude that planting loblolly pine has the highest potential for extending the commercial pine range in the region tested.

BASIC SPECIFIC GRAVITY AND ANATOMY OF Peltophorum dubium WOOD AS A FUNCTION OF PROVENANCE AND RADIAL POSITION

We studied the wood of Peltophorum dubium (Spreng.) Taub. (Fabaceae), popularly known in Brazil as canafístula, from two seed provenances with different climates. The trees were planted in a third place and cut when 28 years old. Based on differences in seed origins, we hypothesized that some differences would be observed in wood density and anatomical features between provenances and that the radial variation pattern would also differ. However, we did not observe any differences in basic specific gravity or anatomical features between the provenances, which may partly be explained by the conservative nature of wood compared with the external characteristics more susceptible to environmental stresses. In fact, based on the literature and our previous findings, radial variation in P. dubium was similar to that found in many native species, including, for example, increase in basic specific gravity, length and wall thickness of the fibers, increase in vessel diameter and decrease in vessel frequency toward the bark. Based on our results, it can be concluded that P. dubium has high plant adaptability in different locations and that consistency in the quality of its wood can be maintained between provenances, with concomitant implications for both production and use.