Comparison of two gas chromatograph models and analysis of binary data

The overall objective of the gas chromatograph system studies is to generate fundamental design criteria and techniques to be used in the optimum design of the system. The particular tasks currently being undertaken are the comparison of two mathematical models of the chromatograph and the analysis of binary system data. The predictions of two mathematical models, an equilibrium absorption model and a non-equilibrium absorption model exhibit the same weaknesses in their inability to predict chromatogram spreading for certain systems. The analysis of binary data using the equilibrium absorption model confirms that, for the systems considered, superposition of predicted single component behaviors is a first order representation of actual binary data. Composition effects produce non-idealities which limit the rigorous validity of superposition

Analysis of chromatograph systems using orthogonal collocation

Research is generating fundamental engineering design techniques and concepts for the chromatographic separator of a chemical analysis system for an unmanned, Martian roving vehicle. A chromatograph model is developed which incorporates previously neglected transport mechanisms. The numerical technique of orthogonal collocation is studied. To establish the utility of the method, three models of increasing complexity are considered, the latter two being limiting cases of the derived model: (1) a simple, diffusion-convection model; (2) a rate of adsorption limited, inter-intraparticle model; and (3) an inter-intraparticle model with negligible mass transfer resistance

Preliminary numerical analysis of improved gas chromatograph model

A mathematical model for the gas chromatograph was developed which incorporates the heretofore neglected transport mechanisms of intraparticle diffusion and rates of adsorption. Because a closed-form analytical solution to the model does not appear realizable, techniques for the numerical solution of the model equations are being investigated. Criteria were developed for using a finite terminal boundary condition in place of an infinite boundary condition used in analytical solution techniques. The class of weighted residual methods known as orthogonal collocation is presently being investigated and appears promising

Predicting criticality and dynamic range in complex networks: effects of topology

The collective dynamics of a network of coupled excitable systems in response to an external stimulus depends on the topology of the connections in the network. Here we develop a general theoretical approach to study the effects of network topology on dynamic range, which quantifies the range of stimulus intensities resulting in distinguishable network responses. We find that the largest eigenvalue of the weighted network adjacency matrix governs the network dynamic range. Specifically, a largest eigenvalue equal to one corresponds to a critical regime with maximum dynamic range. We gain deeper insight on the effects of network topology using a nonlinear analysis in terms of additional spectral properties of the adjacency matrix. We find that homogeneous networks can reach a higher dynamic range than those with heterogeneous topology. Our analysis, confirmed by numerical simulations, generalizes previous studies in terms of the largest eigenvalue of the adjacency matrix.Comment: 4 pages, 3 figure

Effects of network topology, transmission delays, and refractoriness on the response of coupled excitable systems to a stochastic stimulus

We study the effects of network topology on the response of networks of coupled discrete excitable systems to an external stochastic stimulus. We extend recent results that characterize the response in terms of spectral properties of the adjacency matrix by allowing distributions in the transmission delays and in the number of refractory states, and by developing a nonperturbative approximation to the steady state network response. We confirm our theoretical results with numerical simulations. We find that the steady state response amplitude is inversely proportional to the duration of refractoriness, which reduces the maximum attainable dynamic range. We also find that transmission delays alter the time required to reach steady state. Importantly, neither delays nor refractoriness impact the general prediction that criticality and maximum dynamic range occur when the largest eigenvalue of the adjacency matrix is unity

Enhancing sustainability by improving plant salt tolerance through macro-and micro-algal biostimulants

Algal biomass, extracts, or derivatives have long been considered a valuable material to bring benefits to humans and cultivated plants. In the last decades, it became evident that algal formulations can induce multiple effects on crops (including an increase in biomass, yield, and quality), and that algal extracts contain a series of bioactive compounds and signaling molecules, in addition to mineral and organic nutrients. The need to reduce the non-renewable chemical input in agriculture has recently prompted an increase in the use of algal extracts as a plant biostimulant, also because of their ability to promote plant growth in suboptimal conditions such as saline environments is beneficial. In this article, we discuss some research areas that are critical for the implementation in agriculture of macro-and microalgae extracts as plant biostimulants. Specifically, we provide an overview of current knowledge and achievements about extraction methods, compositions, and action mechanisms of algal extracts, focusing on salt-stress tolerance. We also outline current limitations and possible research avenues. We conclude that the comparison and the integration of knowledge on the molecular and physiological response of plants to salt and to algal extracts should also guide the extraction procedures and application methods. The effects of algal biostimulants have been mainly investigated from an applied perspective, and the exploitation of different scientific disciplines is still much needed for the development of new sustainable strategies to increase crop tolerance to salt stress

The transfer of technology from R&D laboratory to industry

The functions of National Research Development Corporation of UK relating to transfer of technology have been stated in the paper. In this connection the programme of work followed by the industry and government sponsored R&D Laboratories of UK the problems encountered, the suggested solutions and the case studies of NRDC have been enumerated. (Mr. P.A. Woodrow, B.Sc, A.I.M., Chief of Production Technology, National Research Development Corporation, U.K.

Nutritional, metabolic and genetic profiling of 'Cerato' and 'Curniciello' bean landraces from Caserta, Southern Italy

Italy represents a territory rich in common bean landraces, most of which have not yet been characterized. Therefore, the proximal composition and metabolic profiles (fatty acid composition, total and free amino acids) as well as total polyphenols and antioxidant capacities of both 'Cerato' and 'Curniciello' dry beans, cultivated in Caserta's rural areas (Southern Italy) were evaluated, in comparison with other local known dry beans. 'Cerato' dry beans have a lower content of crude proteins (21.18 vs 23.41 g/100 g), lipids (1.27 vs 2.08 g/100 g) and total amino acids (16.01 vs. 17.89 g/100 g) with respect to 'Curniciello' dry beans, considering the average values of two different harvest years (2020-2021), although slight statistical differences were found when the two harvest years were analysed separately. Two essential fatty acids (n-6 linoleic and n-3 alpha-linolenic) and oleic acid were the most abundant fatty acids in both dry beans, (similar to 90% of the total). Subsequently, the trypsin and chymotrypsin inhibitory activities in raw and boiled (2 h) dry beans, as well as the a-amylase and a-glucosidase inhibitory activities were investigated, considering their capability to reduce crude protein and carbohydrates intake and assimilation. In addition, AFLP analysis of two landraces shows different polymorphic patterns useful for their authentication and traceability. Overall, our data provide a starting point for promoting the cultivation and consumption of 'Cerato' and 'Curniciello' dry beans, thus contributing to the preservation of local culinary traditions and Italian biodiversity

Habitat Quality Influences Migratory Strategy of Female White Tailed Deer

Partial migration is a life history strategy that is common for ungulate species living in seasonal environments.  One factor that influences the decision to migrate by ungulates is access to high quality habitat.  We evaluated the influence of access to winter habitat of high quality on the probability of an individual migrating, seasonal habitat use between and within migratory and resident classes of deer, and the effects of this decision on the survival of female white-tailed deer.  We radio-collared 67 female white-tailed deer (Odocoileu virginianus) in 2012 and 2013. The odds of being a migrant increased as home range size increased and decreased as proportion of cropland within home range in winter increased.  The habitat with the highest relative probability of use in winter for residents was pasture (1.00, SD = 0.01) and for migrants was riparian (0.73, SD = 0.39). In summer both groups had the highest relative probability of using pasture (resident = 0.96, SD = 0.15; migrant = 0.99, SD = 0.08).  We integrated the migration probability and survival models to estimate annual and seasonal survival rates of migrants and residents. We found no difference between the annual and seasonal rates of survival for the different migration strategies.  Our results indicate that access to habitat of high quality may be a strong influence on a female white-tailed deer’s decision to migrate.  We suggest the presence of partial migration in a population may be a response to competition for high quality habitat