Comparative study of reactivity and agronomic effectiveness of Indian,US, African and Middle East rock phosphates for growing rice

Comparative reactivity and efficiency of eight Indian, six US, two African and one Middle East sources of rock phosphates for growing rice on laterite, red and alluvial soils under flooded conditions were evaluated in pot and laboratory experiments. When applied to moist aerobic soils, 15 days prior to flooding and transplanting rice, all the Indian sources were as poor as theno phosphate control in the three soil types, in respect of P availability in soil, grain yield response and P uptake by rice. North Carolina rock phosphate used in this study was as good as superphosphate in the laterite and red soils, but was also as poor as control in the black soil.NH₄ -citrate was found to interfere in the colorimetric determination of citrate soluble P by the vanado-molybdate colour method. A modified sulpho-molybdate-Sn Cl₂ blue colour method could successfully be used to determine 2–8µg P in the presence of 0.02 to 0.2 meq NH₄ -citrate, especially in rocks containing small amounts of citrate soluble P. All the Indian, as well as Idaho, Missouri and Tennessee rock phosphates were found to be less reactive as they contained much lower amounts of citrate extractable P in eight successive extracts as compared to North Carolina rock phosphate.The cumulative citrate soluble P of 10 rock phosphates determined experimentally in eight successive extracts was significantly correlated with their reported a₀ (length of a axis of unit apatite crystal), mole ratio of CO₃/PO₄ or weight ratio of F/P₂O₅ of rocks. In the absence of X-ray and computer facilities, these regression equations were used to calculate the a₀, CO₃/PO₄, F/P₂O₅, ACS, empirical formula and the apatite content of the unknown Indian rock samples. The Indian rock phosphates had a lower degree of CO₃ and F substitution for PO₄ in the apatite crystal, giving low ACS values and hence were less reactive. This might explain their lower efficiency for direct application for growing rice, obtained in the present experiment. These Indian rock phosphates had also lower apatite content. The use of the statistical method was limited to francolites alone. Scope for the use of this method for other unknown francolite rock phosphate samples has been discussed.     

Design of a Multibus-compatible colour graphics subsystem

Colour graphics subsystems can be used in a variety of applications such as high-end business graphics, low-end scientific computations, and for realtime display of process control diagrams. The design of such a subsystem is shown. This subsystem can be added to any Multibus-compatible microcomputer system. The use of an NEC 7220 graphics display controller chip has simplified the design to a considerable extent. CGRAM (CORE graphics on Multibus), a comprehensive subset of the CORE graphics standard package, is supported on the subsystem.     

Palliative therapy in advanced ovarian cancer: balancing patient expectations, quality of life and cost

The goals of chemotherapy for recurrent/refractory ovarian cancer are the palliation of disease-related symptoms, and improvement of quality and quantity of life. Previous studies of palliative therapy in advanced ovarian cancer have focused on surrogate measures of patient benefit rather than evaluating palliative end-points such as quality of life and clinical benefit. The impact of palliative chemotherapy on survival, quality of life and cost in advanced ovarian cancer are unknown as there have been no studies comparing palliative treatment with best supportive care. Although there is insufficient information from existing studies to determine whether palliative therapy in advanced ovarian cancer is cost-effective, there is some evidence to suggest that chemotherapy has a role in palliation of symptoms with an apparent improvement in quality of life. We relate the results of two studies. (i) A prospective study evaluating the cost of second/third-line chemotherapy as well as its effectiveness, which found the mean total cost per patient for the study period (one line of chemotherapy) was Canadian $12500. In addition, half of patients seemed to derive some palliative benefit and a quarter of patients had an objective response in their disease. (ii) A retrospective study evaluating all costs from the initiation of palliative chemotherapy until death which demonstrated a cost of Canadian $53000 per patient. Our studies demonstrate that patient expectations of palliative therapy in ovarian cancer are high and patients are willing to put up with significant toxicity for modest benefit. Although palliative therapy may be associated with high costs, even modest prolongation of survival can render such treatment cost-effective. The major cost saving associated with palliative therapy is from the reduced need for hospitalization towards the end of life. Future studies in recurrent/refractory ovarian cancer should focus on palliative end-points and include a comparison with best supportive care.     

Invariant-preserving Petri net reduction and conditions for invariant-existence

The use of invariants is an important tool for analysis of distributed and concurrent systems modeled by Petri nets. For a large practical system, the computation of desired invariants by the existing techniques is a time-consuming task. This paper proposes a theoretical foundation for simplified computation of desired invariants. We provide invariant-preserving Petri net reduction rules followed by the conditions for the existence of invariants in various well-structured nets. If an invariant exists, it can be found directly from the net structure using the formulas derived, or by applying the existing techniques on the reduced net.     

Optimum design of stiffened cylindrical panels with constraint on the frequency in the presence of initial stresses

This paper presents the optimum design of stiffened cylindrical panels with weight as the objective function and constraints on the frequencies in the presence of initial stresses, using unconstrained minimization techniques of non-linear mathematical programming problem. The interaction between the buckling constraints and the frequency constraints in the presence of initial stresses are included in the formulation. Loss of load carrying capacity due to imperfection and due to suddenly applied loads are included in the buckling analyses. Results for cylindrical shell are obtained by setting the panel angle to 360 degrees. The relationship between the weight of the cylinder and the panel (a segment of the cylinder) is examined.     

On automated optimum design of trusses

In the course of formulating the automated design of trusses for a project, some hitherto unexplored ideas have been encountered. These ideas are developed in this article.To explore these ideas systematically, truss design for single and multiple load conditions are considered separately. In the first part the applicability of linear programming is illustrated for single load conditions to safeguard against failures by yielding, buckling, and excessive deformations. Postoptimal behaviour of the structure is also studied.In the second part nonlinear programming is used as the design tool for multiple loading conditions. In this procedure, the members are grouped, a fully utilized design is taken as the starting point, and the condensed matrix displacement method of reanalysis is adopted during optimization iterations.Practical design examples of trussed towers are given to illustrate the capabilities of the computer program developed.     

Evaluation of seismic fragility of structures—a case study

The present paper attempts to evaluate the seismic fragility for a typical elevated water-retaining structure. The structure is analysed for two cases: (i) empty tank; and (ii) tank filled with water. The various parameters that could affect the seismic structural response include material strength of concrete and reinforcing steel, effective prestress available in the tank, ductility ratio and structural damping available within the structure, normalised ground motion response spectral shape, foundation and surrounding soil parameters and the total height of water available in the tank. Based on this case study, the seismic fragility of the structure is developed. The results are presented as families of conditional probability curves plotted against peak ground acceleration (PGA) at two critical locations. The procedure adopted, incorporates the various randomness and uncertainty associated with the parameters under consideration.     

Implementation of an interactive relational graphics database

The benefits that accrue from the use of design database include (i) reduced costs of preparing data for application programs and of producing the final specification, and (ii) possibility of later usage of data stored in the database for other applications related to Computer Aided Engineering (CAE). An INTEractive Relational GRAphics Database (INTERGRAD) based on relational models has been developed to create, store, retrieve and update the data related to two dimensional drawings. INTERGRAD provides two languages, Picture Definition Language (PDL) and Picture Manipulation Language (PML). The software package has been implemented on a PDP 11/35 system under the RSX-11M version 3.1 operating system and uses the graphics facility consisting of a VT-11 graphics terminal, the DECgraphic 11 software and an input device, a lightpen.     

Effect of fiber loading and orientation on mechanical and erosion wear behaviors of glass–epoxy composites

For a composite material, its mechanical behavior and surface damage by solid particle erosion depend on many factors. One of the most important factors is the fiber content. Similarly, these properties are also greatly affected by the fiber orientation. In this work, a series of experiments were carried out to investigate the influence of fiber loading and fiber orientation on mechanical and erosion behavior of glass fiber‐reinforced epoxy composites. The composites were fabricated with three different fiber loadings (20, 30, and 40 wt%) and at four different fiber orientations (15°, 30°, 45°, and 60°). The conclusions drawn on the basis of the experimental findings are discussed, and composite with 30° fiber orientation shows better microhardness compared with other fiber orientations irrespective of fiber loading. Similar observations are also noticed for other mechanical properties of the composites, such as tensile strength, flexural strength, interlaminar shear strength, impact strength, etc. Finally, the morphology of eroded surfaces is examined using scanning electron microscopy (SEM), and possible erosion mechanisms are identified. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Physicochemical properties of lactoferrin stabilized oil-in-water emulsions: Effects of pH,salt and heating

Lactoferrin is a globular protein from bovine milk with an unusually high isoelectric point (pI > 8), which may lead to novel functional properties in foods and other products because it is cationic across a wide pH range. In this study, we investigated the influence of pH (2–9), NaCl addition (0–200 mM), CaCl₂ addition (0–200 mM), and thermal processing (30–90 °C, 20 min) on the stability of lactoferrin (LF) stabilized oil-in-water emulsions. At ambient temperature, the emulsions were stable to droplet aggregation at low pH (pH ≤ 6), but exhibited some aggregation at pH ≈ pI (pH 7–9). The thermal stability of the emulsions depended on pH, holding temperature, and thermal history. When LF-coated droplets were heated in distilled water, and then their pH was adjusted in the range 2–9, they were highly unstable to aggregation at pH 7 and 8. On the other hand, when the pH was altered in the range 2–9 first, and then they were heated, the LF-coated droplets were highly unstable to aggregation at pH ≥ 5 when heated above 50 °C. The stability of the emulsions to salt addition depended on pH and salt type, which was attributed to counter-ion binding and electrostatic screening effects. For NaCl, emulsions were stable from 0 to 200 mM at pH 3 and 9, but aggregated at ≥100 mM at pH 6. For CaCl₂, emulsions were stable from 0 to 200 mM at pH 3, but aggregated with ≥150 mM CaCl₂ at pH 6 and 9. These results have important implications for the formulation and production of emulsion-based products using lactoferrin as an emulsifier.