Swelling Factor Research Articles

Numerical modeling of CO2 diffusion into water-oil liquid system using moving mesh technique

A new diffusion model is developed to study the mass diffusion of CO2 in the water-oil liquid system. The diffusion stages are divided by the position of diffused CO2 front in the liquid system. The 1st and 2nd diffusion stages are performed to characterize the CO2 diffusion in individual oil phase and in water-oil liquid system, respectively. The Peng-Robinson equation of state combined with the diffusion model of two stages are developed to describe the diffusion process of CO2 in the water-oil liquid system. The developed model is validated by matching the pressure changes results of model calculation with an experimental acquisition. Besides, a moving mesh technique is applied to determine the oil swelling effect caused by the CO2 diffusion. The results indicate that both CO2 concentration profiles and oil swelling effect exhibit distinct characteristics at different stages. The CO2 distributes only in the oil phase at the 1st diffusion stage but presents simultaneously in both water and oil phases at the 2nd diffusion stage. The oil swelling factors are 0.90% and 10.84% at the end of the 1st (t = 12.8 h) and 2nd (t = 512.8 h) diffusion stages, respectively.

Optimization Method for Determination of Swelling Factor Linum usitatissimum Seeds

Aim: Aspire of the investigation is to amend the method for determination of swelling factor of seeds, so it can be determined to optimize the minimum errors which will be reproducible. Swelling factor is play key role if the phytoconsitituent rich in mucilage and polysaccharide which constitute a diverse class of biological macromolecules. Background: Sugar molecules play a broad range of physiochemical properties which are widely used for applications in Pharmacy and the present investigation work is related to determine the effect of parameters such as quantity of seed, volume and nature of solvent, time interval of agitation, time of measurement of result, Effect of quantity of seeds on swelling factor determination. Solvent Optimized technic gives superlative results over IP method. Methods: The swelling factor of Linum usitatissimum was evaluated by using different polar to non-polar solvents by using the standard procedure. During the determination, the role of physical parameter were calculated by comprising the swelling factor with agitation and temperature. Results: According to the observations, the lower concentration levels of swelling index used as an alternative binder to starch. keeping one parameter as variable while all other parameters constant, it was observed that the swelling index of gives better results using the solvents plain distilled water, seeds moistened with alcohol. It was also observed that agitation at every three hours till the process of 24 hours is maintained would give better results, keeping one parameter as variable while all other parameters constant.

Formation and characterisation of hydrogel diffusion channels for directed drug delivery

Abstract Drug Delivery Systems (DDS) are frequently operating in a surrounding liquid environment, such as blood in the case of drug-eluting stents or perilymph in the case of cochlear implants. However, there is also a demand for systems with sustained drug release in predominantly dry environments, mostly consisting of ambient air. Examples are the treatment of diseases located in the middle ear or the paranasal sinuses. On the one hand, due to the lack of transportation media, the functionality of a polymer/drug combination for delayed release would be limited in such environments. On the other hand, these environments are generally equipped with mucus membranes. Hence, a somewhat humid surrounding is ensured. In this study, a concept of a hydrogel equipped DDS for drug delivery through the round window membrane is presented, addressing two objectives. First objective is to ensure the drug transport by serving as a diffusion channel. For instance the route to the drug target destination, the round window membrane, can be provided by a hydrogel. The second objective is to ensure the adhesion to the membrane. Two promising approaches are presented in this study: The photo induced immobilisation of PEGDA700, as well as the immobilisation of chitosan on poly(l-lactid) (PLLA). For both approaches PLLA specimen had to be modified with oxygen plasma followed by activation for crosslinking with subsequent immobilisation of the hydrogel. With these methods a layer thickness of at least 5 μm was achieved. All steps were characterized with contact angle measurements. After the immobilization of the hydrogel, the swelling factor, as well as the layer thickness was examined.

Phase behavior and fluid interactions of a CO2-Light oil system at high pressures and temperatures

This paper investigates the phase behavior and mutual interactions between a light crude oil and CO2 at high pressures and high temperatures (HPHT). To do so, we have measured PVT properties of the CO2-oil system at HPHT using a PVT setup. We have also tried to present a detailed methodology for measuring PVT properties of CO2-oil systems and highlight the difficulties such as oil vaporization by CO2 during the experiments. A crude oil sample, collected from a Malaysian oil field, was used here. Our experiments indicated that, CO2 solubility in the oil increased at higher pressures when measured at a fixed temperature. Our experiments also showed that increasing the test temperature would reduce CO2 solubility in the oil, while its effect is more significant at higher pressures. The swelling factor (SF) measurements showed an increasing trend with pressure up to a certain value so-called extraction pressure, at which, the SF started to be reduced even became less than one. The measurements of oil viscosity indicated that CO2 dissolution in the oil sample could reduce the mixture viscosity up to 61%. The interfacial tensions between CO2 and the crude oil at different pressures were also measured while the results were used to estimate the minimum miscibility pressure (MMP) and the first contact miscibility (FCM) pressure. The IFT measurements at various pressures displayed a reduction trend as a result of more CO2 dissolution in the oil but with two different slopes. That is, at lower pressure values, the measured IFTs were sharply reduced with pressure, while the reduction rate of the IFT became less when pressures exceeded the extraction pressure. This study helps with determining the optimum pressure and temperature conditions of CO2-oil systems to have a minimum IFT, a maximum CO2 solubility and SF, and a minimum oil viscosity that are favorable for CO2-enhanced oil recovery projects. Additionally, the methodology presented here gives guidelines on how to design PVT experiments of CO2-oil systems for petroleum and chemical engineering applications.

Laboratory measurements of solubility and swelling factor for CO2/Brine and CO2/heavy oil binary systems under low‐medium pressure and temperature

AbstractAn extensive experimental study was performed to investigate the effect of various parameters such as temperature, pressure, and crude oil API gravity on the fluid interactions in the binary systems of brine‐CO2 and two heavy oil‐CO2 systems. The solubility of CO2 in 20 000 ppm brine solution was measured at various experimental conditions. The solubility of CO2 and swelling factor, due to the CO2 dissolution, of two heavy crude oil samples (type‐I: °API = 20.44 and type‐II: °API = 15.49) were experimentally measured at various operating conditions.Results showed that the solubility of CO2 in heavy oil increased when the experimental pressure increased, and when the experimental temperature decreased. At a constant pressure of Pexp = 3.44 MPa, the solubility of the CO2 was measured to be 10.13, 5.72 g CO2/100 g oil in the type‐I crude oil when the temperature increased from T = 21 to 45 °C. Increasing the experimental pressure from Pexp = 1.38 MPa to 3.44 MPa at a constant temperature of T = 21 °C increased the solubility of the CO2 from 2.37 to 7.84 g CO2/100 g oil in the type‐II crude oil. The reduction in the oil API gravity had an adverse effect on the CO2 solubility. At a temperature of T = 21 °C and a pressure of Pexp = 3.44 MPa, the CO2 solubility decreased from ∼10.13 in the type‐I oil to 7.84 g CO2/100 g oil in the type‐II oil. The measured values of the swelling factor showed that the type‐I and type‐II crude oils could exhibit a maximum swelling factor of 1.079 and 1.052 at a temperature of T = 21 °C and a pressure of Pexp = 3.44 MPa.

Phase equilibrium calculations in shale gas reservoirs

Compositional multiphase flow in subsurface porous media is becoming increasingly attractive due to issues related with enhanced oil recovery, CO 2 sequestration and the urgent need for development in unconventional oil/gas reservoirs. One key effort to construct the mathematical model governing the compositional flow is to determine the phase compositions of the fluid mixture, and then calculate other related physical properties. In this paper, recent progress on phase equilibrium calculations in unconventional reservoirs has been reviewed and concluded with authors’ own analysis, especially focusing on the special mechanisms involved. Phase equilibrium calculation is the main approach to investigate phase behaviors, which could be conducted using different variable specifications, such as the NPT flash and NVT flash. Recently, diffuse interface models, which have been proved to possess a high consistency with thermodynamic laws, have been introduced in the phase equilibrium calculation, incorporating the realistic equation of state (EOS), e.g. Peng-Robinson EOS. In the NVT flash, the Helmholtz free energy is minimized instead of the Gibbs free energy used in NPT flash, and this thermodynamic state function is decomposed into two terms using the convex-concave splitting technique. A semi-implicit numerical scheme is applied to the dynamic model, which ensures the thermodynamic stability and then preserves the fast convergence property. A positive definite coefficient matrix is designed to meet the Onsager reciprocal principle so as to keep the entropy increasing property in the presence of capillary pressure, which is required by the second law of thermodynamics. The robustness of the proposed algorithm is demonstrated by using two numerical examples, one of which has up to seven components. In the complex fluid mixture, special phenomena could be captured from the global minimum of tangent plane distance functions and the phase envelope. It can be found that the boundary between the single-phase and vapor-liquid two phase regions shifts in the presence of capillary pressure, and then the area of each region changes accordingly. Furthermore, the effect of the nanopore size distribution on the phase behavior has been analyzed and a multi-scale scheme is presented based on literature reviews. Fluid properties including swelling factor, criticality, bubble point and volumetrics have been investigated thoroughly by comparing with the bulk fluid flow in a free channel. Cited as : Zhang, T., Li, Y., Sun, S. Phase equilibrium calculations in shale gas reservoirs. Capillarity, 2019, 2(1): 8-16, doi: 10.26804/capi.2019.01.02

A laboratory investigation of carbon dioxide-enhanced oil recovery by focusing on CO2-oil physical properties

Carbon dioxide (CO2) miscible flooding has become an important method in enhanced oil recovery (EOR) for recovering residual oil. In addition it may help in protection of the environment as (CO2) is widely viewed as an important agent in global warming. Knowledge of the interactions between (CO2) and reservoir crude oil is very critical for any (CO2)-enhanced oil recovery (EOR) projects. This paper shows the effect of (CO2) miscible flooding application for Egyptian oil fields by swelling studies. The swelling test is a laboratory simulation of the process of injecting gradually different percentage of (CO2) gas into a reservoir containing under-saturated oil. The gas (injection solvent) can dissolve, causing the reservoir fluid to swell. This paper presents a summary of a wide range of laboratory tests conducted on ten different crude oils varying from 26.4 to 40.5 API. These were used to invested the use of (CO2) and its effect on parameters such as viscosity, density, gas solubility and swelling factor as a function of pressure at temperature from 620.3 to 706.0 °R.

Study of CO2 molecular diffusion effect on the production of fractured reservoirs: The role of matrix porosity, and a new model for predicting the oil swelling factor

The study of carbon dioxide injection into fractured reservoirs is of great importance, because carbon dioxide is the most effective greenhouse gas in the global warming phenomenon; moreover, being the residual oil in the matrix of fractured reservoirs is significant, with the injection of carbon dioxide into the fractured reservoirs, various mechanisms are involved which reduce the amount of residual oil, among which, the most important are: gravity drainage, molecular diffusion, oil swelling, viscosity reduction, evaporation and extraction. In the present study, we have two goals. The first one is the extension of previous studies of CO2 molecular diffusion effects on single block modeling of fractured reservoirs considering three porosities, 11%, 26% and 44%. For the porosity effect study, it is observed that, at a higher porosity, the viscosity decreases later, and the duration of viscosity reduction as well as increase in viscosity, or oil swelling and oil evaporation mechanism, is longer. Also, the higher the porosity of the matrix, the greater the effect of the molecular diffusion on the oil recovery. The second goal is to present a new model which calculates the oil swelling factor. In this regard, Fick’s second law is applied to a constant pressure diffusion cell considering the corresponding initial and boundary conditions. Then, taking into account the works by Kendall Marra et al. (1988), swelling model, by modifying the gridding and initial conditions, a new moving boundary swelling factor numerical model is presented. The model results are compared with measured experimental swelling factor data, which show good compatibility.

Development of surface-attached thin film of non-fouling hydrogel from poly(2-oxazoline)

In this study poly(2-ethyl-2-oxazoline) (PEOXA) chains that contains 11 mol% of benzophenone molecules was synthesized and coated on either 3-ethoxybenzophenonesilane-modified inorganic or bare organic substrates. Upon irradiation under UV light, the photo-active benzophenone molecules enabled the formation of polymer network as well as attachment of the polymer network onto the substrates. Important variables for the generation of hydrogel film with high gel content and stability, such as the heat treatment for solvent removal, the UV wavelength (that determines the irradiation energy), and the input of energy dose were varied and their influence to the gel content and stability of the hydrogel film was studied. The thickness, lifetime of benzophenone, and chemical composition of the film were determined using ellipsometry, UV/Vis spectroscopy, and XPS methods, respectively. On a film that has been exposed to physiological buffer for 14 days, XPS results indicated that chemical degradation of the copolymer did not take place. Ellipsometry results, however, indicated that some portion of the film detached and the remaining thickness was dependent on the input of energy dose during the hydrogel preparation. It was shown that when suitable conditions are applied during preparation, a stable surface-attached PEOXA-based hydrogel, i.e. approximately 78% gel content and 75–90% stability after 30 days of incubation in physiological buffer, could be generated on the surface. Dry and swollen thicknesses of the stable surface-attached film measured from AFM experiments revealed a swelling factor of 1.7. Furthermore, the AFM morphology image showed a homogenous polymer film with an average roughness of 30 nm. Protein adsorption test revealed that the resulting surface-attached PEOXA-based hydrogel film on PMMA substrate hinders BSA adsorption to the same extent as the reference system generated from benzophenone-bearing poly(dimethylacrylamide) (PDMAA).

STRUCTURAL, FUNCTIONAL PROPERTIES AND IN VITRO DIGESTIBILIGY OF MAIZE STARCH UNDER HEAT-MOISTURE AND ATMOSPHERIC-COLD PLASMA TREATMENTS

Maize starch is one of an important material which widely using in food applications and other industries. However, natural properties of raw starch can not be suitable for processed foods. So, the modification of starch is very important. In this study, heat-moisture and atmospheric cold argon-plasma treatments were applied in maize starch; then, structural, fuctional properties and digestibility of modified starch was investigated. Raw starch was heated at 20, 25 and 30% of moisture content. Subsequently, sample was treated under argon-plasma environment at fixed paramentes (137,5 V; 1.0 A for 10 min). Sample was investigated degree of cross-linking, degree of relative crystallinity (DRC), degree of hydrolysis using alpha-amylase, in vitro digestibility, changes in the hydration properties such as water absorbance index, swelling factor and water solubility index. Results show that degree of cross-linking, DRC, resistant starch of samples significantly increase under heat-moisture and plasma treatments; especially, sample of 20% heat-moisture contains 3-folded to 10-folded increase comparing to raw starch base on with or without pre-boiling process. Furthermore, water absorbance index and swelling factor decrease but water solubility index increase under plasma treatment.

Computational Characterization of Ultrathin Polymer Membranes in Liquids

Polymer membranes are ubiquitously utilized in a wide variety of technological applications; thus, the characterization and fundamental understanding of their properties in relevant working environment are indispensable. In this study, we develop a methodology to computationally characterize the microscopic structures and properties of polymer membranes in liquids by integrating atomistic simulations and two characteristic lengths; the characteristic lengths are proposed from the concept of Gibbs dividing surface. The methodology is illustrated for the swelling of an ultrathin polymer of intrinsic microporosity (PIM-1) membrane in different solvents (acetone, acetonitrile, methanol, ethanol, and water). Specifically, the swelling dynamics is examined by time-dependent solvent content and radius of gyration in the membrane inner layer. The simulated swelling factors are found to agree well with available experimental data. In the five solvents, the predicted swelling degrees follow the experimentally measu...

Aberrant expression of the innate restriction factor bone marrow stromal antigen-2 in primary Sjögren's syndrome

ObjectiveThe objective of this study was to analyze bone marrow stromal antigen-2 (BST-2) levels in labial glands, total peripheral blood mononuclear cells (PBMCs) and PBMC subpopulations from primary Sjögren's syndrome (pSS) patients and determine the correlation between BST-2 expression and clinical characteristics. Materials and methodsPBMC subsets were positively separated using magnetic microbeads. BST-2 mRNA levels in labial glands, total PBMCs and PBMC subsets of 30 pSS and 30 healthy control (HC) subjects were investigated using real-time polymerase chain reaction (RT-PCR). Distribution of BST-2-positive cells in the labial glands was assessed by immunohistochemistry. ResultsBST-2 was significantly increased in pSS labial glands and was positively correlated with the VAS value for parotid gland swelling and rheumatoid factor and β2-microglobulin serum levels. BST-2 levels were statistically different between pSS patients with positive and negative expression of anti-SSA antibody. Positive focal infiltrating lymphocytes and adjacent ductal epithelial cells were observed in labial glands from pSS patients, while there were a few scattered positive ductal epithelial cells in controls. BST-2 was also up-regulated in CD19+ B cells and the remaining CD4-CD8-CD19- PBMCs. ConclusionBST-2 was aberrantly expressed in pSS patients, and expression in labial glands was positively correlated with important clinical characteristics; thus, it may be a potential biomarker of pSS activity.

Cell permeable HMGB1-binding heptamer peptide ameliorates neurovascular complications associated with thrombolytic therapy in rats with transient ischemic stroke

BackgroundBlood–brain barrier (BBB) breakdown and inflammatory responses are the major causes of tissue-type plasminogen activator (tPA)-induced hemorrhagic transformation (HT), while high-mobility group box 1 (HMGB1) exacerbates inflammatory damage to BBB during the process of brain ischemia/reperfusion. This study aimed to investigate the change of HMGB1 after thrombolytic therapy and whether blocking HMGB1 could ameliorate the neurovasculature complications secondary to tPA treatment in stroke rats.MethodsSera from acute stroke patients and rats with thrombolytic therapy were collected to investigate HMGB1 secretion. Male Sprague-Dawley rats with 2 h or 4.5 h middle cerebral artery occlusion were continuously infused with tPA followed by administration of membrane permeable HMGB1-binding heptamer peptide (HBHP). The mortality rate, neurological score, HT, brain swelling, BBB permeability, and inflammatory factors were determined.ResultsThe results revealed that HMGB1 levels were elevated in both stroke patients and rats after tPA treatment. Blocking HMGB1 signaling by HBHP in the rat model of 4.5 h brain ischemia significantly attenuated tPA-related complications, including mortality rate, the degree of hemorrhage, brain swelling, neurological deficits, BBB impairment, microglia activation, and the expressions of inflammatory cytokines.ConclusionstPA treatment might induce HMGB1 secretion while blocking HMGB1 with HBHP could markedly reduce the risk of thrombolysis-associated brain hemorrhage and mortality through attenuating BBB damage and inflammatory reactions. These results indicate that HMGB1 may potentiate the risk of HT in tPA administration and that blocking HMGB1 signaling would be helpful in preventing complications brought by thrombolysis in ischemic stroke.Trial registrationhttp://www.chictr.org.cn. Unique identifier: ChiCTR-OOC-16010052. Registered 30 November 2016.

Acoustic investigation of CO2 mass transfer into oil phase for vapor extraction process under reservoir conditions

Generally, researchers to study mass transfer of gas phase into liquid use pressure decay method, visual cell or pendant drop technique. Despite available data about CO2 solubility in oil, there are limited methods which allow to study interactions between fluids. In this paper, a newly developed acoustic pulse-echo (APE) technique was applied to measure oil volume expansion factors in the presence of carbon dioxide in a pressure range of 2–6 MPa at a temperature of 297 K to cover most practical cases of interest for the vapor extraction process. With the APE technique, a wave is emitted from a piezoelectric transducer, and its reflection from the boundary is detected at a later time. As CO2 becomes soluble in the oil, the boundary between the fluids moves upward, thus affecting the travel time of the reflected wave from the fluid interface. Since volume changes are registered, the expansion factor can be evaluated. The experimental results show that the oil swelling factor increases with pressure; this clearly indicates that there are certain correlations between the oil swelling factor and the solubility of an oil-solvent system. The evidence for the validity of the acoustic technique was provided by comparing measured values with literature data. Compared to other investigatory approaches, the main advantage of this newly developed method is its ability to provide highly accurate swelling factor values for CO2/oil system. The method developed in this study can be serviceable for further and more complex investigations on gas-EOR experiments.

A New Application of the Differential Quadrature Element-Incremental Method in Moving-Boundary Problems

Diffusion of solvent gas in heavy oil and bitumen is essential in solvent-based heavy oil recovery. The pressure decay technique used for prediction of gas diffusion coefficient in heavy oil ignores the role of changes in gas compressibility factor and oil swelling. In this work, a numerical approach is proposed to model gas diffusion in bitumen from pressure decay data which includes all complexities due to oil swelling and gas compressibility factor. The proposed model was solved using differential quadrature element-incremental method. Results showed that changes in gas compressibility factor and swelling factor are significant and cannot be overlooked while interpreting pressure decay data. For diffusion of gas in bitumen, swelling was more significant at upper sub-layers adjacent to the gas phase. Also, swelling is more pronounced in the upper bitumen layers in contact with gas and stabilizes at later times when the gas concentration reaches equilibrium at the interface.

Modeling and optimization of dough recipe for breadsticks

During the work, the authors studied the combined effect of non-traditional raw materials on indicators of quality breadsticks, mathematical methods of experiment planning were applied. The main factors chosen were the dosages of flaxseed flour and grape seed oil. The output parameters were the swelling factor of the products and their strength. Optimization of the formulation composition of the dough for bread sticks was carried out by experimental- statistical methods. As a result of the experiment, mathematical models were constructed in the form of regression equations, adequately describing the process of studies. The statistical processing of the experimental data was carried out by the criteria of Student, Cochran and Fisher (with a confidence probability of 0.95). A mathematical interpretation of the regression equations was given. Optimization of the formulation of the dough for bread sticks was carried out by the method of uncertain Lagrange multipliers. The rational values of the factors were determined: the dosage of flaxseed flour - 14.22% and grape seed oil - 7.8%, ensuring the production of products with the best combination of swelling ratio and strength. On the basis of the data obtained, a recipe and a method for the production of breadsticks "Idea" were proposed (TU (Russian Technical Specifications) 9117-443-02068106-2017).

Hybrid connectionist model determines CO2\u2013oil swelling factor

In-depth understanding of interactions between crude oil and CO2 provides insight into the CO2-based enhanced oil recovery (EOR) process design and simulation. When CO2 contacts crude oil, the dissolution process takes place. This phenomenon results in the oil swelling, which depends on the temperature, pressure, and composition of the oil. The residual oil saturation in a CO2-based EOR process is inversely proportional to the oil swelling factor. Hence, it is important to estimate this influential parameter with high precision. The current study suggests the predictive model based on the least-squares support vector machine (LS-SVM) to calculate the CO2–oil swelling factor. A genetic algorithm is used to optimize hyperparameters (γ and σ2) of the LS-SVM model. This model showed a high coefficient of determination (R2 = 0.9953) and a low value for the mean-squared error (MSE = 0.0003) based on the available experimental data while estimating the CO2–oil swelling factor. It was found that LS-SVM is a straightforward and accurate method to determine the CO2–oil swelling factor with negligible uncertainty. This method can be incorporated in commercial reservoir simulators to include the effect of the CO2–oil swelling factor when adequate experimental data are not available.

Competitive Adsorption of Xylene and Toluene on Modified and Unmodified Magnesium Exchanged Bentonite Clay Mineral

Cetyltrimethylammonium bromide (CTAB) – modified and unmodified magnesium exchanged bentonite were used for the competitive adsorption of m-xylene and toluene from their aqueous solution. Infrared spectroscopy (IR, adsorption capacity and Foster swelling measurements were performed using Fourier Transform Infrared Spectrophotometer to evaluate the performance of the adsorbents. The FT-IR results indicated that the quaternary ammonium salts (Cetyltrimethylammonium bromide) were intercalated between the layers of the bentonite clay. The Foster swelling test results indicated that the affinity of CTAB occurred in the treated clay as tested in all organic solvents (diesel, kerosene, gasoline, toluene and m-xylene), with and without agitation. The result showed that modified magnesium bentonite swelled more than the unmodified and the order of the swelling factor is; m- xylene > toluene > gasoline > diesel > DPK > water. However, when the assay was performed under agitation, it yielded higher swelling capacity and all the organic solvents used in this investigation showed good compatibility after organophilization. The modified clay exhibited very high capacity of adsorption compared to unmodified samples. The m-xylene and toluene uptake follows a pseudo second order kinetics mechanism, suggesting that the rate determining step of adsorption involves the two adsorbates competitively adsorbed on the adsorbent sites. Modified magnesium bentonite has a higher percentage removal and higher adsorption capacity than raw or unmodified magnesium bentonite. These adsorbents (modified magnesium bentonite) are therefore recommended for use by water treatment and petrochemical industries for removal of hydrocarbons (m- xylene and toluene) from their waste water and effluents.

Características físicas e anatômicas da madeira de Tectona grandis L.f. aos 7 anos de idade

This work aimed at the physical and anatomical characterization of Tectona grandis wood obtained from thinning, at 7 years. Five commercially planted trees were selected and wood discs were cut in different base-top positions (0, 25, 50, 75 and 100% of the total height) for the determination of wood basic density and samples were obtained in three radial positions to fibers (length, width, diameter of lumen and wall thickness) and vessels (diameter, occupied area and frequency) dimensions. Tortoises were also cut from the basal area of the trunk and test specimens were obtained to determine wood retractability (retraction, swelling and anisotropic factor). The mean wood density found was 0.40 g.cm-3. The mean values of axial and radial retraction, volumetric retractability and anisotropic retraction factor are considerably high, indicating dimensional instability of the species. The evaluations of the physical and anatomical characteristics of wood indicated that the structures formed by the cambium have not yet reached the stabilization of their dimensions, and it is not indicated for the applications of the adult Teak wood as in the construction naval and furniture.

Genetic architecture of some agronomic traits as deciphered from diallel cross analysis of Plantago ovata Forsk

From a collection of 105 genetic stocks of Plantago sp., a 7 × 7 diallel analysis was conducted for the estimation of gene action in seven parents in Plantago ovata. Using Hayman's Graphical (Wr – Vr graphs) model we analyzed the gene action for fourteen agronomic traits. The traits – days to 50% flowering, plant height, branches per plant, panicles per plant, peduncle length, panicle length, panicle weight per plot, days to maturity, seed yield per plot, inflorescence husk yield per plot, husk yield per plot and 100 seed weight exhibited overdominance whereas, leaf area and swelling factor exhibited partial dominance. The pattern of distribution of the seven parents along the regression line deciphered the absence of recessive genes in most of the traits.