Heat treatment effects on extraction of roselle (Hibiscus sabdariffa L) seed oil

Fatty acid composition of roselle (Hibiscus sabdariffa L) seed oil was determined and oil extraction was optimized using RSM. Five levels of the variables, roasting duration (10, 15, 20, 25, and 30 min), and temperature (80, 90, 100, 110, and 120°C) were used. Oil yield (OY), free fatty acid (FFA), anisidine value (AV), specific gravity (SG), and stability were responses and determined using standard methods. Major fatty acids found were oleic acid (37.92%), linoleic (35.01%), palmitic (19.65%), and stearic (6.07%). Myristic (0.16), myristoleic (0.17), palmitoleic (0.56), arachidic (0.14), and eicosatrienoic (0.20) were minor fatty acids content. OY, FFA, AV, SG, and stability varied from 18 to 23%, from 0.56 to 4.11%, from 6.93 to 35.7 mg/L, from 0.90 to 0.95, and from 0.68 to 5.42%, respectively. The treatment had significant (p<0.05) effect on OY, AV, and SG. However, non‐significant effect of treatment was recorded on FFA and stability at 5% level of significance. The best desirability of 0.46 was achieved at roasting duration and temperature of 25 min and 110°C, respectively, which gave OY of 22%, initial FFA of 1.95%, AV of 31.2 mg/L, SG of 0.92, and stability of 2.67%. Practical applications: Roselle seed is a by‐product from the processing of roselle calyces. Reports from literature have shown that the seed contains about 20% edible health‐promoting oil. Research into effect of pre‐heat treatment on quality and quantity of oil extracted from roselle seed will serve as a guide in recommending optimum heating duration and temperature. The models developed in this study can be a working tool for producers of roselle oil extraction equipment and potential investors into commercial production of roselle oil. Output of this work may change the status of the seeds from a waste material to a valuable product.     

Inverted Hockey Stick Method Quantifies Price Uncertainty in Petroleum Investment Evaluation

In this paper, we present a new method for quantifying the uncertainty of economic projections due to uncertainty in future oil prices. Traditionally, the petroleum industry has employed what are known as “hockey stick” price forecasts, i.e., monotonically increasing price profiles, in economic calculations to evaluate investment opportunities. Calculations are often run using most-likely, optimistic, and pessimistic price profiles in an attempt to quantify the uncertainty in the resulting economic indicators. These conventional hockey stick methods significantly underestimate uncertainty because they do not reproduce the volatility inherent in oil prices. Stochastic methods that attempt to model price volatility have been used successfully and indicate that there is considerably more uncertainty in oil and gas development projects than has been previously recognized. However, many operators do not use stochastic methods for modeling oil prices, most likely because they require more time and effort to implement than conventional methods.

The Inverted Hockey Stick method presented herein is similar to conventional methods in that only three price realizations are run to quantify uncertainty. However, the high and low cases are designed to better capture the range of possible future price paths. Uncertainty ranges for economic indicators predicted by the new method are comparable to 70-95% probability ranges predicted by the stochastic bootstrap method, significantly greater than the 32-42% ranges predicted by conventional methods. This new method can be easily incorporated into existing economic modeling systems. Recognition of the greater uncertainty in oil and gas investment opportunities, both upside as well as downside, should improve investment decision making.     

In vitro and in vivo evaluation of sustained-release and enteric-coated microcapsules of diclofenac sodium

This work examines the release of diclofenac sodium from ethylcellulose (EC) microcapsules made up of different drug to polymer ratios. The release process was found to follow the Higuchi square root equation and not the zero-order or first order equations. However, for drug to polymer ratio of 1:1, a critical time (θ) was reached beyond which the release rate was lower than that predicted on the basis of the Higuchi square root equation. Dissolution experiments in 0.1N HCL revealed that less than 1.5% of the encapsulated drug was released in 6 h. This finding indicates the suitability of the EC microcapsules for enteric-coated preparations. The in vitro release of diclofenac sodium from microcapsules of different drug to polymer ratios was compared with that from a commercial sustained-release product. A distinct similarity between the release profile of the commercial product with that obtained for the 1:2 drug to polymer microcapsules was noted. The in vivo work included determination of the serum drug profile following oral administration of the microcapsules and the commercial product to rabbits. The obtained serum concentration time profile of the EC microcapsules exhibited a sustained-release pattern similar to the commercial product and consistent with the in vitro results.     

The effects of cobalt substitution on the thermal diffusivity of YBa2Cu3O7−δ superconductor

The thermal diffusivity κ(T) of the cobalt-substituted sintered YBCO system, YBa₂Cu_3?x Co _x O_7∮δ (x=0.0, 0.1), has been measured to, investigate, effects of atomic substitution and charge carrier concentration on the thermal diffusion processes. The thermal diffusivity was measured in the temperature range 35–300 K, using the transient-plane-source technique. The results show that, belowT _c , the κ(T) values of the doped (x=0.1), samples are lower than the corresponding values for the undoped (x=0.0) samples. This may be due to the difference in the free-charge carrier concentrations of the two samples. A decoupling between the conducting Cu?O planes as a result, of Co-doping in the chain sites may contribute to additional decrease in the thermal diffusivity of the doped sample. An attempt was made to explain the rise in the thermal diffusivity belowT _c by adopting a recent theoretical model based on the existence of weakly damped collective electron excitations of Bose type, with acoustic dispersion relation, (acoustic plasmons) inside the superconducting gap.     

Coding schemes variation and its impact on string hashing

This paper presents the results of investigating the impact of variations found in character coding schemes on the performance of string hashing. The investigation involved three types of Arabic strings (single words, personal names, and document titles) and four different Arabic coding schemes. The results were examined in three different respects: collision rates, arithmetic code redundancy, and the contribution of arithmetic redundancy to the collision rate. Two items are considered arithmetically redundant, if they have the same numerical coding value. Even though the mathematical properties of coding schemes showed some impact on the hashing results, coding scheme variation was basically reflected in the results of hashing on single dictionary words. Where a difference was noted in the rates of arithmetic redundancy, it was accompanied by different growth patterns of collision. The results seem to indicate that the arithmetic properties of the collating sequence of a given coding scheme are likely to have some impact on the performance of string hashing.     

A mathematical model of interaction of the results of different R&;D types

A three-dimensional model of exchange among different R&D types, i.e., basic articles, applied articles, and patents on inventions, has been constructed and investigated within the linear concept of innovations and equations of population dynamics. With linear functions for growth coefficients from phase variables, all eight critical points of the constructed third-order dynamic system were found.     

Thermophysical properties of fly ash–Cu hybrid nanofluid for heat transfer applications

The effect of temperature and concentration on the thermophysical properties of fly ash–copper (80% fly ash and 20% Cu by volume) water-based stable hybrid nanofluid is studied. The experiments are conducted for the volume concentration range of 0 to 0.5% in the temperature range of 30 to 60°C. The nanoparticles have been characterized by transmission electron microscopy and dynamic light scattering to determine an average nanoparticle diameter of 15 nm. The stability of nanofluid in the presence of surfactant Triton X-100 is examined with the help of zeta potential. The maximum enhancement in thermal conductivity and viscosity is 19% and 22%, respectively. The outcome of the present study showed that density, thermal conductivity, and viscosity of the hybrid nanofluid increased, whereas specific heat decreased with an increase in the nanofluid concentration. In addition, the specific heat and thermal conductivity increase, there is a decrease in density and viscosity of the hybrid nanofluid with an increase in temperature.     

Transport properties of blended sulfonated poly(styrene-isobutylene-styrene) and isopropyl phosphate membranes

This work discusses the effect of isopropyl phosphate (IP) on the transport properties of sulfonated poly(styrene-isobutylene-styrene) (SO₃H SIBS) as membranes for direct methanol fuel cell (DMFC) and chemical and biological protective clothing (CBPC) applications. The properties were determined as a function of SIBS sulfonation level (i.e., 24, 34, 49, and 84 mol %) and IP loading (i.e., 1, 3, 5, 11, and 15 wt %). A comprehensive material characterization study (e.g., FTIR, TGA, AFM, and SAXS) was performed to confirm the presence of the phosphate groups in the polymer matrix, assess the thermal stability of the proton-exchange membranes (PEMs), and understand how the unique interactions between the phosphate and sulfonic groups influenced the nanostructure of SO₃H SIBS. The transport properties, water absorption capabilities (i.e., swelling ratio, water uptake, etc.), oxidative stability, and ion-exchange capacity (IEC) were performed to evaluate the impact of IP on the properties of the resulting solvent-casted membranes. Results suggest that the morphology, thermal stability, and vapor permeability are governed by the sulfonation level, whereas the IEC, oxidative stability, water absorption capabilities, and the rest of the transport properties are dominated by the ionic content (i.e., sulfonic and phosphate groups) and their synergistic effects. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47009.