105 research outputs found
STUDY OF FATTY ACID COMPOSITION OF MILK FOR CHEESE PRODUCTION
The article shows that the studied samples of raw milk in terms of composition (mass fraction of fat, protein, lactose and milk solids-not-fat) met the criteria of suitability for cheese, and its physic-chemical properties (titratable acidity, density, freezing point) were within acceptable limits. Moreover, rennet sample corresponded to the first and second classes. It was proved that the number of spores of lactating fermenting microorganisms met the requirements for milk for the production of any kind of cheese. It was established that the fatty acid composition of raw cow’s milk used to produce cheeses at various enterprises varied significantly. The data indicate the variability of the content of all groups of fatty acids — low molecular weight, saturated, monounsaturated and polyunsaturated. As a result of gas chromatography studies using the chromatographic complex «Chromos GX-1000» with a flame ionization detector and a CP 88 quartz capillary column — Sil 88 for FAME100 m × 0.25 mm × 0.2 µm, it was found that the largest absolute fluctuations were for saturated (± 7.03 % of the average value) and monounsaturated fatty acids (± 3.77 % of the average value). Absolute fluctuations in the group of low molecular weight fatty acids amounted to ± 2.62 %, and in the group of polyunsaturated — ± 1.02 % of the average value. The calculation of the relative deviation showed that the most varied groups were the ones of low molecular weight fatty acids (± 28.40 rel.%) and polyunsaturated fatty acids (± 25.11 rel.%). At the same time, a relatively high content of certain fatty acids: myristoleic, palmitic, palmitoleic and low levels of stearic and oleic fatty acids, was revealed in individual milk samples.The article shows that the studied samples of raw milk in terms of composition (mass fraction of fat, protein, lactose and milk solids-not-fat) met the criteria of suitability for cheese, and its physic-chemical properties (titratable acidity, density, freezing point) were within acceptable limits. Moreover, rennet sample corresponded to the first and second classes. It was proved that the number of spores of lactating fermenting microorganisms met the requirements for milk for the production of any kind of cheese. It was established that the fatty acid composition of raw cow’s milk used to produce cheeses at various enterprises varied significantly. The data indicate the variability of the content of all groups of fatty acids — low molecular weight, saturated, monounsaturated and polyunsaturated. As a result of gas chromatography studies using the chromatographic complex «Chromos GX-1000» with a flame ionization detector and a CP 88 quartz capillary column — Sil 88 for FAME100 m × 0.25 mm × 0.2 µm, it was found that the largest absolute fluctuations were for saturated (± 7.03 % of the average value) and monounsaturated fatty acids (± 3.77 % of the average value). Absolute fluctuations in the group of low molecular weight fatty acids amounted to ± 2.62 %, and in the group of polyunsaturated — ± 1.02 % of the average value. The calculation of the relative deviation showed that the most varied groups were the ones of low molecular weight fatty acids (± 28.40 rel.%) and polyunsaturated fatty acids (± 25.11 rel.%). At the same time, a relatively high content of certain fatty acids: myristoleic, palmitic, palmitoleic and low levels of stearic and oleic fatty acids, was revealed in individual milk samples
Improved approximation algorithm for k-level UFL with penalties, a simplistic view on randomizing the scaling parameter
The state of the art in approximation algorithms for facility location
problems are complicated combinations of various techniques. In particular, the
currently best 1.488-approximation algorithm for the uncapacitated facility
location (UFL) problem by Shi Li is presented as a result of a non-trivial
randomization of a certain scaling parameter in the LP-rounding algorithm by
Chudak and Shmoys combined with a primal-dual algorithm of Jain et al. In this
paper we first give a simple interpretation of this randomization process in
terms of solving an aux- iliary (factor revealing) LP. Then, armed with this
simple view point, Abstract. we exercise the randomization on a more
complicated algorithm for the k-level version of the problem with penalties in
which the planner has the option to pay a penalty instead of connecting chosen
clients, which results in an improved approximation algorithm
Synthesis and application of cobalt and polyoxomolybdatecontaining alumina systems
The work is devoted to the synthesis and study of the activity of cobalt and polyoxomolybdate-containing alumina catalyst. The synthesized catalytic system was characterized using the following analysis methods: scanning electron microscopy, x-ray phase analysis, x-ray diffraction analysis, IR spectroscopy. It was found that the CoMo/Al[2]O[3] system is active in the hydrodesulfurization reaction of model raw materials
Composition of Initiated Cracking Products of High-sulfur Natural Bitumen
The analysis of the cracking products of bitumen Karmalskoye deposits (the content of fractions boiling up to 200 °C 6,7% wt.) has been performed. The influence of power plant coal ash microspheres on orientation of cracking bitumen components is stated. Bitumen cracking leads to significant yields of gas and coke for more than 20% wt. and destructions of all components. The initiated bitumen cracking in the presence of 10% microspheres at cracking temperature 450 °C leads to reduction of gas and coke yields and increase in fractions of ibp (initial boiling point) –360 °C at 10% wt. in comparison with products of the thermal bitumen cracking. The analysis of composition and amount of sulfur compounds in initial bitumen and the cracking products in the various conditions has shown that the thermal cracking leads to increased homologues benzothiophene contents due to partial destruction of resins, and to decrease in the content of homologues dibenzothiophene
Composition of Pre-ozonated High-Sulfur Natural Bitumen Cracking Products
The results analysis of fractional and material composition of the cracking products of Ashalchinskoye and Karmalskoye bitumen deposits was presented in this work. The effect of bitumen ozone-oxygen mixture pretreatment followed by cracking on thermolysis processes was investigated. It was shown that molecules of resins and asphaltenes containing large amounts of aliphatic fragments in its structure readily undergo thermal decomposition to form additional distillate fractions. Low content of aliphatic fragments leads to aromatization of the naphthenic cycles in the molecule of resins and asphaltenes, the thermal degradation reactions proceed in high yields of gas and coke
Constrained Non-Monotone Submodular Maximization: Offline and Secretary Algorithms
Constrained submodular maximization problems have long been studied, with
near-optimal results known under a variety of constraints when the submodular
function is monotone. The case of non-monotone submodular maximization is less
understood: the first approximation algorithms even for the unconstrainted
setting were given by Feige et al. (FOCS '07). More recently, Lee et al. (STOC
'09, APPROX '09) show how to approximately maximize non-monotone submodular
functions when the constraints are given by the intersection of p matroid
constraints; their algorithm is based on local-search procedures that consider
p-swaps, and hence the running time may be n^Omega(p), implying their algorithm
is polynomial-time only for constantly many matroids. In this paper, we give
algorithms that work for p-independence systems (which generalize constraints
given by the intersection of p matroids), where the running time is poly(n,p).
Our algorithm essentially reduces the non-monotone maximization problem to
multiple runs of the greedy algorithm previously used in the monotone case.
Our idea of using existing algorithms for monotone functions to solve the
non-monotone case also works for maximizing a submodular function with respect
to a knapsack constraint: we get a simple greedy-based constant-factor
approximation for this problem.
With these simpler algorithms, we are able to adapt our approach to
constrained non-monotone submodular maximization to the (online) secretary
setting, where elements arrive one at a time in random order, and the algorithm
must make irrevocable decisions about whether or not to select each element as
it arrives. We give constant approximations in this secretary setting when the
algorithm is constrained subject to a uniform matroid or a partition matroid,
and give an O(log k) approximation when it is constrained by a general matroid
of rank k.Comment: In the Proceedings of WINE 201
Strategic Priorities of Municipal Development Based on Identifying the Interests of Stakeholders: Methodological Approaches and Practical Implementation
The formation of documents for strategic planning of socio-economic development is the most important task of regional and municipal governments. It can be stated that strategic planning processes have been launched throughout the country and the process of forming these documents is active at both the regional and municipal levels. However, the issues of determining, studying, and taking into account the views of interested parties when forming the goals and priorities of socio-economic development of administrative-territorial entities require methodological support and recommendations for practical implementation. In this article, an attempt is made to reveal methodological approaches and solve issues of practical implementation of identifying the interests of stakeholders on the example of a specific municipality.The proposed material is an example of determining and scientifically substantiating the strategic priorities of a municipality on identifying the interests of stakeholders.The study of the processes of formation and determination of strategic priorities for the development of a municipality based on the identification of the interests of all interested parties should become the task of further research
Experimental demonstration of near-infrared negative-index metamaterials
Metal-based negative refractive-index materials have been extensively studied in the microwave region. However, negative-index metamaterials have not been realized at near-IR or visible frequencies due to difficulties of fabrication and to the generally poor optical properties of metals at these wavelengths. In this Letter, we report the first fabrication and experimental verification of a transversely structured metal-dielectricmetal multilayer exhibiting a negative refractive index around 2 mu m. Both the amplitude and the phase of the transmission and reflection were measured experimentally, and are in good agreement with a rigorous coupled wave analysis
Review on uranium in soil: levels, migration
The problems of radioactive contamination of biosphere with the 238U in recent years have attracted a large number of experts in various fields of knowledge. Natural radionuclides are an integral part of the biosphere. They are concentrated everywhere: in rocks, in soil, water, air and food. Various types of phosphorus fertilizers and other natural ameliorants used in agriculture are also an additional source of heavy natural radionuclides. The review describes the behaviour and migration of 238U in biosphere, which depend on various factors acting simultaneously. It is noted that the behaviour of 238U in the soil depends on the forms of its presence in it and the physical and chemical properties of the soil. The processes of sorption and desorption of 238U by different soil types are significant indicators
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