492 research outputs found
Effect of hydroxybenzoic acids antioxidants on the oxidative stability of sardine oil
The antioxidant capacities of three derivatives of hydroxybenzoic acids (Gentisic acid, protochatechuic acid and vanillic acid) in sardine oil were compared. Peroxide value, conjugated diene value, p-anisidine value and thiobarbituric acid reactive substances (TBARS) value were assessed to determine the oxidative stability provided by these substances to the sardine oil. Results showed that gentisic acid (2,5 dihydroxy benzoic acid) was the most effective of the chosen hydroxybenzoic acids in imparting oxidative stability to the sardine oil. Protochatechuic acid (3,4 dihydroxy benzoic acid) provided relatively less oxidative stability, while vanillic acid had no effect. Results from this work showed that the position of hydroxylation and methyl substitution influences the antioxidant capacity of the molecules in sardine oil. Furthermore, it was found that the extent of oxidative stability conferred by the antioxidants in lipid systems is influenced by several other physical and chemical factors as well
Screening of polymeric membranes for membrane assisted deacidification of sardine oil
The diversification in fish oil use and the need for softer processing demand new oil refining processes. In considering the advantages of membrane technology, three different membranes (polyamide (PA), polytetrafluoroethylene (PTFE) and polyethersulfone (PES)) were used in this particular study. Preliminary results in the separation of free fatty acids (FFA) from glycerides of sardine oil/ethanol mixtures using a single dead end microfiltration mode have been reported here. The influence of experimental factors like pressure and oil/ethanol ratios (w/v) on the permeate flux and the reduction of FFA (%) in the permeate was studied. PTFE membrane showed promising results in terms of residual FFA in permeate (%), % oil loss (15.12%, 5.45%) as compared to PA (20.50%, 6.66%) and PES membranes (20.60%, 8.92%). PA membrane showed a higher flux of 4.4 L/m2 /h, followed by PTFE 3.34 L/m2 /h and PES, 1.19 L/m2 /h at 3.5 bar trans-membrane pressure. These results showed that using PTFE membrane could be an ideal strategy for the membrane assisted deacidification of sardine oil using solvents
On the nature of gravitational forces
In this paper I show how the statistics of the gravitational field is changed
when the system is characterized by a non-uniform distribution of particles. I
show how the distribution functions W(dF/dt) giving the joint probability that
a test particle is subject to a force F and an associated rate of change of F
given by dF/dt, are modified by inhomogeneity. Then I calculate the first
moment of dF/dt to study the effects of inhomogenity on dynamical friction.
Finally I test, by N-Body simulations, that the theoretical W(F) and dF/dt
describes correctly the experimental data and I find that the stochastic force
distribution obtained for the evolved system is in good agreement with theory.
Moreover, I find that in an inhomogeneous background the friction force is
actually enhanced relative to the homogeneous case
The Final State of Black Strings and p-Branes, and the Gregory-Laflamme Instability
It is shown that the usual entropy argument for the Gregory-Laflamme (GL)
instability for appropriate black strings and -branes gives
surprising agreement up to a few percent. This may provide a strong support to
the GL's horizon fragmentation, which would produce the array of
higher-dimensional Schwarzschild-type's black holes finally. On the other hand,
another estimator for the size of the black hole end-state relative to the
compact dimension indicates a second order (i.e., smooth) phase transition for
some appropriate compactifications and total dimension of spacetime
wherein the entropy argument is not appropriate. In this case,
Horowitz-Maeda-type's non-uniform black strings or -branes can be the final
state of the GL instability.Comment: More emphasis on a second order phase transition. The computation
result is unchange
A unification in the theory of linearization of second order nonlinear ordinary differential equations
In this letter, we introduce a new generalized linearizing transformation
(GLT) for second order nonlinear ordinary differential equations (SNODEs). The
well known invertible point (IPT) and non-point transformations (NPT) can be
derived as sub-cases of the GLT. A wider class of nonlinear ODEs that cannot be
linearized through NPT and IPT can be linearized by this GLT. We also
illustrate how to construct GLTs and to identify the form of the linearizable
equations and propose a procedure to derive the general solution from this GLT
for the SNODEs. We demonstrate the theory with two examples which are of
contemporary interest.Comment: 8 page
Exact solutions of coupled Li\'enard-type nonlinear systems using factorization technique
General solutions of nonlinear ordinary differential equations (ODEs) are in
general difficult to find although powerful integrability techniques exist in
the literature for this purpose. It has been shown that in some scalar cases
particular solutions may be found with little effort if it is possible to
factorize the equation in terms of first order differential operators. In our
present study we use this factorization technique to address the problem of
finding solutions of a system of general two-coupled Li\'enard type nonlinear
differential equations. We describe a generic algorithm to identify specific
classes of Li\'enard type systems for which solutions may be found. We
demonstrate this method by identifying a class of two-coupled equations for
which the particular solution can be found by solving a Bernoulli equation.
This class of equations include coupled generalization of the modified Emden
equation. We further deduce the general solution of a class of coupled ordinary
differential equations using the factorization procedure discussed in this
manuscript.Comment: Accepted for publication in J. Math. Phy
Traditional Knowledge on the Edibility of Sea urchin roe among the Fisher folk Community of the Gulf of Mannar region with a note on their Cuisine
Sea urchins are marine echinoderms and their body consists of five gonads covered by a calcareous test. The gonads of male and female sea
urchins are commonly called ‘roe’ and have been known a delicacy in several parts of the world. However in India not all the coastal community
eat the gonads of sea urchin, but fishers of a fishing village along Gulf of Mannar, have the habit of consuming the sea urchin roe for centuries. There are a variety of
sea urchin recipes viz., Risotto with Sea Urchin-Dill, and Smoked Caviar-Sea Urchin Mousse with Ginger Vinaigrette, Sea Urchin Bruschetta and Sea Urchin Linguine
available in the western world, but in India the cuisine of sea urchin roe is not well known, the present study documented for the first time on the two cooking
methods viz., Grilling and dry fry of sea urchin roe from the fisherfolk community of Gulf of Mannar region
A randomised feasibility study to investigate the impact of education and the addition of prompts on the sedentary behaviour of office workers
Abstract Background Office workers have been identified as being at risk of accumulating high amounts of sedentary time in prolonged events during work hours, which has been associated with increased risk of a number of long-term health conditions. There is some evidence that providing advice to stand at regular intervals during the working day, and using computer-based prompts, can reduce sedentary behaviour in office workers. However, evidence of effectiveness, feasibility and acceptability for these types of intervention is currently limited. Methods A 2-arm, parallel group, cluster-randomised feasibility trial to assess the acceptability of prompts to break up sedentary behaviour was conducted with office workers in a commercial bank (n = 21). Participants were assigned to an education only group (EG) or prompt and education group (PG). Both groups received education on reducing and breaking up sitting at work, and the PG also received hourly prompts, delivered by Microsoft Outlook over 10 weeks, reminding them to stand. Objective measurements of sedentary behaviour were made using activPAL monitors worn at three time points: baseline, in the last 2 weeks of the intervention period and 12 weeks after the intervention. Focus groups were conducted to explore the acceptability of the intervention and the motivations and barriers to changing sedentary behaviour. Results Randomly generated, customised prompts, delivered by Microsoft Outlook, with messages about breaking up sitting, proved to be a feasible and acceptable way of delivering prompts to office workers. Participants in both groups reduced their sitting, but changes were not maintained at follow-up. The education session seemed to increase outcome expectations of the benefits of changing sedentary behaviour and promote self-regulation of behaviour in some participants. However, low self-efficacy and a desire to conform to cultural norms were barriers to changing behaviour. Conclusions Prompts delivered by Microsoft Outlook were a feasible, low-cost way of prompting office workers to break up their sedentary behaviour, although further research is needed to determine whether this has an additional impact on sedentary behaviour, to education alone. The role of cultural norms, and promoting self-efficacy, should be considered in the design of future interventions. Trial registration This study was registered retrospectively as a clinical trial on ClinicalTrials.gov (ID no. NCT02609282 ) on 23 March 2015
Functional characterization of generalized Langevin equations
We present an exact functional formalism to deal with linear Langevin
equations with arbitrary memory kernels and driven by any noise structure
characterized through its characteristic functional. No others hypothesis are
assumed over the noise, neither the fluctuation dissipation theorem. We found
that the characteristic functional of the linear process can be expressed in
terms of noise's functional and the Green function of the deterministic
(memory-like) dissipative dynamics. This object allow us to get a procedure to
calculate all the Kolmogorov hierarchy of the non-Markov process. As examples
we have characterized through the 1-time probability a noise-induced interplay
between the dissipative dynamics and the structure of different noises.
Conditions that lead to non-Gaussian statistics and distributions with long
tails are analyzed. The introduction of arbitrary fluctuations in fractional
Langevin equations have also been pointed out
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