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AHEAD OF PRINT

Tom 9 (2022): Zeszyt 2 (July 2022)

Tom 9 (2022): Zeszyt 1 (March 2022)

Tom 8 (2021): Zeszyt 3 (November 2021)

Tom 8 (2021): Zeszyt 2 (July 2021)

Tom 8 (2021): Zeszyt 1 (March 2021)

Tom 7 (2020): Zeszyt 3 (November 2020)

Tom 7 (2020): Zeszyt 2 (July 2020)

Tom 7 (2020): Zeszyt 1 (March 2020)

Tom 6 (2019): Zeszyt 2 (December 2019)

Tom 6 (2019): Zeszyt 1 (March 2019)

Tom 5 (2018): Zeszyt 2 (December 2018)

Tom 5 (2018): Zeszyt 1 (March 2018)

Tom 4 (2017): Zeszyt 1 (March 2017)

Tom 3 (2016): Zeszyt 1 (March 2016)

Tom 2 (2015): Zeszyt 1 (December 2015)

Informacje o czasopiśmie
Format
Czasopismo
eISSN
2603-347X
Pierwsze wydanie
15 Dec 2015
Częstotliwość wydawania
1 raz w roku
Języki
Angielski

Wyszukiwanie

Tom 4 (2017): Zeszyt 1 (March 2017)

Informacje o czasopiśmie
Format
Czasopismo
eISSN
2603-347X
Pierwsze wydanie
15 Dec 2015
Częstotliwość wydawania
1 raz w roku
Języki
Angielski

Wyszukiwanie

20 Artykułów
access type Otwarty dostęp

Editorial Note: Where Science Meets Art

Data publikacji: 09 Feb 2017
Zakres stron: 5 - 5

Abstrakt

access type Otwarty dostęp

Synthesis and properties of N-alkyl(phenyl)amido-O-methyl-1,2-alkadienephosphonates

Data publikacji: 09 Feb 2017
Zakres stron: 6 - 12

Abstrakt

Abstract

The synthesis of the titled compounds has been described. Their reactivity towards electrophilic and nucleophilic reagents has been investigated.

Słowa kluczowe

  • 1,2-alkadienephosphonates
  • 2,5-dihydro- 1,2-oxaphospholes
  • ⃞-ketophosphonates
access type Otwarty dostęp

Interaction of 1,2-Alkadienephosphonic thioesters with sulphenyl- and selenenylbromide

Data publikacji: 09 Feb 2017
Zakres stron: 13 - 18

Abstrakt

Abstract

The reactivity of thioesters of 1,2-alkadienephosphonic acids toward sidphenyl- and selenenyl bromides has been investigated.

Słowa kluczowe

  • 1,2-aikadienephosphonates
  • phenylsulphenyl bromide
  • phenylselenenyl bromide
access type Otwarty dostęp

Evolutions and equilibrium parameters of foam films from individual solutions of Bovine serum albumin, n-dodecyl-β-D-maltoside and from their mixed solutions

Data publikacji: 09 Feb 2017
Zakres stron: 19 - 28

Abstrakt

Abstract

The evolutions of thinning of films from individual solutions of BSA, C12G2 and from their mixed solutions with molar ratios 1:1, 1:7.5, 1:50 and 1:100 with pH = 4.9 were recorded by modified (with video camera) interferometric method. Based on them the stages through which the film goes from its formation to the equilibrium state were distinguished. It was shown that: (i) the difference between the kinetic of drainage of films stabilized by high and low molecular surfactants is drastic; (ii) only the change of the pH solution under or above isoelectric point strongly retards the film drainage; (iii) the transition of the kinetic of thinning of films from mixed solutions from a kinetic typical for high molecular substances towards a kinetic for low substances depends on the molar ratio between the components in the solution. From the picture of film corresponding to its equilibrium state the type of film was determined. From the analysis of this picture the equilibrium thickness and contact angle were calculated. It was found that the criterion for Newtonium black films (based on the values of film thickness and contact angle) is not directly applicable for films from protein solutions or mixed solutions with the participation of proteins.

Słowa kluczowe

  • Bovine Serum Albumin (BSA)
  • n-dodecyl - β -D maltoside (C12G2)
  • mixed BSA/ C12G2 solutions
  • film evolution
  • equilibrium thickness
  • contact angle.
access type Otwarty dostęp

Descriptor Fingerprints and Their Application to Red Wine Clustering and Discrimination

Data publikacji: 09 Feb 2017
Zakres stron: 29 - 33

Abstrakt

Abstract

The investigation was performed to test the potentials of the fingerprint clustering algorithm for a set of 1599 red wines in relation to some wine properties, comprised in the notion “wine quality”. We have obtained a distribution of the wines into different clusters as a result. Each cluster was composed of wine-objects with similar values of laboratory parameters and with a wine quality certificate. A correlation between the. quality of wines (a sensory taste factor) and the phisicochemical descriptors (laboratory analytical test results data) was observed and analyzed.

Słowa kluczowe

  • similarity search
  • descriptor fingerprints
  • red wine clustering
access type Otwarty dostęp

Experimental studies on equilibrium adsorption isosteres and determination of the thermodynamic quantities of polar media on alumina Al2O3

Data publikacji: 09 Feb 2017
Zakres stron: 34 - 45

Abstrakt

Abstract

The present work is a revieif of theoretical and experimental study on the adsorption performance of the adsorbent Alumina (Al2O3) used in the adsorption system. An experimental investigation on the equilibrium adsorption isosteres at low pressure (< 1 atm) of working pairs Al2O3/H2O and Al2O3/C2H6O2 is carried out. The isovolume measurement method is adopted in the test setup to directly measure the saturated vapor pressures of working pairs at vapor-liquid equilibrium (dG=0 and dμi=0). Quantity adsorbed is determined from pressure, volume and temperature using gas law. The isosteric heat of adsorption is calculated from the slope of the plot of lnP versus 1/T different amounts of adsorbate onto adsorbent as follows: 0,01 vol% Al2O3/H2O; 0,03 vol% Al2O3/H2O; 0,1 vol% Al2O3/H2O; 0,01 vol% Al2O3/C2H6O2; 0,03 vol% Al2O3/C2H6O2; 0,1 vol% Al2O3/C2H6O2. This study shows that adsorption working pair Al2O3 C2H6O2 has better adsorption performances than those of the A2O3/H2O. Surface acidity! is a most important property! far both adsorption and catalysis and therefore is examined structure of active sites of alumina surface. Thermodynamic parameters such as isosteric heat of adsorption, isosteric enthalpy and entropy of adsorption are critical design variables in estimating the performance and predicting the mechanism of an adsorption process and are also one of the basic requirements for the characterization and optimization of an adsorption process

Słowa kluczowe

  • heterogenous acid-base catalyzer
  • surface acidity
  • polar organic solvent
  • isosteric heat of adsorption
  • isosteric enthalpy and entropy of adsorption
access type Otwarty dostęp

Allelopathic activity of Nepeta nuda L. subsp. nuda water extracts

Data publikacji: 09 Feb 2017
Zakres stron: 46 - 51

Abstrakt

Abstract

Nepeta nuda subsp. nuda is a medicinal plant growing wild in Bulgaria. Different species of Nepeta genus have been reported to possess allelopathic potential. The present study was conducted to observe its phytotoxic effects on T. aestivum and C. sativus L. seeds in laboratory conditions. Nepeta water extracts (NWE) prepared from aerial parts of plants at concentrations 2, 4, 6, 8, 10, 12 and 14 g/l were tested. The rate of seed germination, the root and shoot length, fresh and dry weight of seedlings were observed after treatment with NWE. As a control served seeds treated with distilled water. Germination was not affected, but NWE showed deterioration in seedling growth. Roots were more affected than shoots. The fresh and dry weights were reduced upon treatment with the extracts tested. These negative effects were dose-dependent. The overall results indicate presence of water soluble allelochemicals in Nepeta nuda subsp. nuda.

Słowa kluczowe

  • Nepeta nuda subsp. nuda
  • allelopathy
  • root and shoot growth inhibition
  • fresh and dry weight
access type Otwarty dostęp

Covalent immobilization of rabbit-antiaflatoxin-antibodies onto the poly-acrylamideacrylonitrile as well as hybrid material UREASIL and developing an optical immunosensor

Data publikacji: 09 Feb 2017
Zakres stron: 52 - 56

Abstrakt

Abstract

The aim of this work is to describe a covalent immobilization of antibodies onto the poly- acrylamide-acrylonitrile or hybrid material UREASIL and creation of optical immunosensor for determination of aflatoxin Bl. For this purpose, mouse-anti-aflatoxin B1 antibodies with oxidized carbohydrate moieties were covalently immobilized on the membranes of polyacrylamide- polyacrylonitrile copolymer, as well as the hybrid material UREASIL. To determine the affinity> binding of the immobilized antibody with afatoxin Bl was used "sandwich" method. Associated with the immobilized antibody sought ingredients interact with a surplus of secondary’ signal antibodies. The described method has been developed as a model system, which can easily be applied for the determination of aflatoxins in samples of different origin. To the best of our knowledge, this is the first study to show that in the establishment of biosensor was used hybrid material UREASIL.

Słowa kluczowe

  • aflatoxin B1
  • immunosensor
  • optical Biosensor
  • immobilization
  • antibody
access type Otwarty dostęp

Mazer’s theory application in Bi4Ge3O12:V

Data publikacji: 09 Feb 2017
Zakres stron: 57 - 60

Abstrakt

Abstract

The recent development of coherent light amplifiers and oscillators, now generally referred to as optical masers “or lasers,” has made feasible a host of new uses and applications of electromagnetic wave energy in the optical portion of the spectrum. Furthermore, the high degree of monochromaticity obtainable from an optical maser makes it a useful tool for spectroscopic investigations as well as for stimulating various types of chemical and physical reactions. The effect of vanadium doping transforms Bi4Ge3O12 single crystals into optical maser. This result can be observed after thermoluminescence at 556 nm.

Słowa kluczowe

  • optical maser
  • vanadium doping
  • Shrödinger’s time-dependent equation
access type Otwarty dostęp

Electronic setup for fluorescence emission measurements and long-time constant-temperature maintenance of Single-Walled Carbon Nano-Tubes in water solutions

Data publikacji: 09 Feb 2017
Zakres stron: 61 - 69

Abstrakt

Abstract

In our previous research we have observed that the fluorescence emission from water solutions of Single-Walled Carbon Nano-Tubes (SWCNT), excited by a laser with a wavelength of 830nm, diminishes with the time. We have already proved that such a fading is a function of the storage time and the storage temperature. In order to study the emission of the SWCNT as a function of these two parameters we have designed and realized a special measurement compartment with a cuvette holder where the SWCNT solutions can be measured and stored at a fixed constant temperature for periods of time as long as several weeks. To maintain the measurement setup under a constant temperature we have designed special experimental setup based on two Peltier cells with electronic temperature control.

Słowa kluczowe

  • SWCNT
  • Single Walled Carbon Nanotubes
  • fluorescence
  • Peltier cell
access type Otwarty dostęp

Fish Lipids as a Valuable Source of Polyunsaturated Fatty Acids

Data publikacji: 09 Feb 2017
Zakres stron: 70 - 75

Abstrakt

Abstract

This article presents information about omega-3 (h-3) and omega-6 (n-6) polyunsaturated fatty acid (PUFA) contents in a broad range of commercially important fish species available on Bulgarian fish markets. The aim is to raise consumers’ awareness and encourage them to eat fish. Fish species from the Black Sea coast have relatively high proportion of n-3 PUFAs, of which more than 80% is by EPf (eicosapentaenoic acid, C 20:5 n-3) and DHA (docosahexaenoic acid, C 22:6 n-3). Extensive epidemiological studies show that fish consumption is inversely associated with the incidence of cardiovascular diseases (CVD), stroke and the functioning of the brain. About 0.5 g of omega-3 (EPA+DHA) a day or two savings of oily fish a week are required to reduce the risk of death from CVD. PUFAs needs should be satisfied not only with food additives but with fish lipids containing food.

Słowa kluczowe

  • omega-3
  • omega-6
  • Black Sea fish
  • health benefits
access type Otwarty dostęp

Nutritional status in short-term overtraining boxers

Data publikacji: 09 Feb 2017
Zakres stron: 76 - 83

Abstrakt

Abstract

The diet is essential to the recovery process in athletes, especially those undergoing intensive training. The continuous imbalance between loading and recovery leads to development of overtraining syndrome. The purpose of this study was to establish the changes in the nutritional status of short-term overtrained athletes. Twelve boxers from the team of National Spoils Academy Sofia, Bulgaria during their preparation for the National Championship 2016 were studied. The measurements were conducted three times.in the beginning of preparation (T1), 22 days later (2) and 10 days after (32 days after first measurement), in the beginning of the recovery period, one week prior the competition (T3).The measurements included basic anthropometric data, overtraining questionnaire RESTO-Sport and nutrition questionnaire, plasma concentration of testosterone and cortisol.On the data of dietary survey the percent proportion and the amount of daily consumed proteins, fats and carbohydrates were defined and the energy intake of the tested athletes was calculated. According to the RESTO-Sport a significant decrease in the ratio stress/recovery was observed in the period with the heaviest training load T2, and an increase was estimated in the pre­competition recovery period T3. It was found a typical for the overtraining syndrome decrease in the concentration of testosterone and the ratio of testosterone/cortisol in T3. In some respondents a reduction in carbohydrates and proteins intake was observed in T2 and especially in T3, which correlates with the hormonal changes. In this work the diet changes was discussed as a possible consequence and/or a cause of the overtraining syndrome.

Słowa kluczowe

  • cortisol
  • nutrition
  • overtraining
  • sports
  • testosterone
access type Otwarty dostęp

Diagnosis of the socionic temperament of personality and creating a psychological portrait of the Western European SPA and wellness tourists in Bulgaria

Data publikacji: 09 Feb 2017
Zakres stron: 84 - 88

Abstrakt

Abstract

Human personality is a set of psychological characteristics that distinguishes it from others. However people can be classified as congenital personality types, interactions that are precisely defined. The aim of this article is to characterize the socionic temperament and psychological profile of the spa and wellness tourists in Bulgaria. The study is based on a survey of 460 tourists who visited Bulgarian spa centers in the summer and autumn of 2015.

Słowa kluczowe

  • spa and wellness
  • western European tourists
  • socionic temperament
  • psychological profile
access type Otwarty dostęp

Morphostructure of the Sakar and Strandzha Mountains

Data publikacji: 09 Feb 2017
Zakres stron: 89 - 93

Abstrakt

Abstract

The Sakar and Strandzha Mountains are disposed in the South-East end of the Balkan Peninsula (on the both sides of the Bulgarian-Turkish boundary). They belong to the southeastern margin of the Bulgarian continental microplate. They are limit from North Thracian morphostructural zone to the North, the East Thracian morphostructural zone to the South and the Rhodopean morphostructural zone to the West. The observed mountain territory builds the Sakar-Strandzha morphostructural zone. It is divided by Sakar Dervent and Strandzha morphostructural areas. Every of them include morphostructural regions. They are composed by numerous Late Pleistocene-Holocene dome-like morphostructures. The relics from the Post Early Pleistocene concentric morphostructures are distributed in the entire zone. They were determined some archer and concentric Holocene mountain morphostructures.

The regional seismic activity (during the last 50 years) outlines three parts of the Sakar-Strandzha morphostructural zone. The western one - the Sakar part is moderate seismic active. The centred - Dervent part is practically seismic „calm“. The eastern one- Strandzha part show a very intensive seismicity. It can by given right in a future (after the necessary investigations) to divide the zone in three areas.

Słowa kluczowe

  • morphostructural writs
  • morphostructural generations
  • mountain morphostructures
access type Otwarty dostęp

Geomorphology of outflow part Batova river valley

Data publikacji: 09 Feb 2017
Zakres stron: 94 - 99

Abstrakt

Abstract

Firths are geomoiphological and hydrological sites typical for flat, neutral coast of no tidal sea basins. There in the greatest extend is preserved the geological column of the correlative Pleistocene- Holocene sediments. They make possible to reveal the Quaternary evolution of the contact zone „land-sea“. Firths are one of the most reliable indicators for the Quaternary Earth crust movements.

Along the Black Sea coast most widely are developed the firths in the north - west and the west periphery, where they form a classic firth type coast.

This report examines the results of complex studies of Batova river firth, located (developed) on the North Bulgarian Black Sea coast.

Słowa kluczowe

  • firth (liman)
  • coastline
  • neutral type of coast
  • Quaternary movements
access type Otwarty dostęp

The Impact of Environmental Factors on the Amount of Nitrates and Nitrites in Different Types of Soils and Ways of Their Utilization

Data publikacji: 09 Feb 2017
Zakres stron: 100 - 105

Abstrakt

Abstract

Despite the last decade considerable advances in the study of nitrate and nitrite pollution of soil, there are still some gaps in research related to neglecting or ignoring the role of soil in the food chain and its effects on upper trophic units. The article presents the results of a study on the impact of air and soil humidity and temperature, as well as soil type and utilization on the amount of nitrates and nitrites in the soil solution at the end of vegetation period. It was proved that statistically significant impact on the amounts of residual nitrate and nitrite ions was caused by the temperature and moisture of soil, its type, and the specific properties of the crops grown.

Słowa kluczowe

  • nitrates
  • nitrites
  • pollution of soils
  • soil types
access type Otwarty dostęp

The regional approach and regional studies method in the process of geography teaching

Data publikacji: 09 Feb 2017
Zakres stron: 106 - 117

Abstrakt

Abstract

We define the regional approach as a manner of relations among the global trends of development of the “Society-man-nature” system and the local differentiating level of knowledge. Conditionally, interactions interlace under the influence of the character of Geography as a science, education, approaches, goals and teaching methods.

Global, national and local development differentiates in three concentric circles at the level of knowledge. It is determined as a conception of modern, complex and effective mechanism for young people, through which knowledge develops in regional historical and cultural perspective; self-consciousness for socio-economic and cultural integration is formed as a part of the. historical-geographical image of the native land. This way an attitude to the. native land is formed as a connecting construct between patriotism to the motherland and the same in global aspect.

The possibility for integration and cooperation of the educative geographical content with all the local historical-geographical, regional, profession orientating, artistic, municipal and district institutions, is outlined.

Contemporary geographical education appears to be a powerful and indispensable mechanism for organization of human sciences, while the regional approach and the application of the regional studies method stimulate and motivate the development and realization of optimal capacities for direct connection with the local structures and environments.

Słowa kluczowe

  • geography
  • teaching
  • education
  • methods
  • didactics
  • approach
access type Otwarty dostęp

Implementing Interactive Teaching Methods for 9th Grade Organic Chemistry Classes

Data publikacji: 09 Feb 2017
Zakres stron: 118 - 123

Abstrakt

Abstract

One of the main challenges facing the current educational system is creating conditions suitable for academic skill development that allow students to navigate and adapt to today’s modern society, such as locating relevant information quickly as well as effectively utilizing innovations. We can achieve this objective by using interactive teaching methods. These methods take into account the contemporary issues and changing priorities - from the general content building for the courses to independent, student-centered cognitive activities.

The propose of this paper is to present tested and proven interactive methods for Grade 9Organic Chemistry classes. These methods significantly improve the quality of teaching and the students’ interest in the subject.

Słowa kluczowe

  • teacher training
  • organic chemistry
  • interactive methods
access type Otwarty dostęp

Expectations of the Educational Reform of High School Geography

Data publikacji: 09 Feb 2017
Zakres stron: 124 - 132

Abstrakt

Abstract

The study is an attempt to present the latest developments in legislation for implementation of the reform in geographic education in secondary school. Through conducted survey has been taken into account the views and expectations of teachers of Geography and Economics in terms of the new law, a framework curriculum, State educational standards and curricula. Expectations of educational reform are formulated as positive and negative sides. Referred to a recommendation for overcoming some of the problems were identified.

Słowa kluczowe

  • educational reform
  • school geographical education
access type Otwarty dostęp

Climate Change, Risks and Natural Resources didactic issues of educational content geography of Bulgaria and the world in 9th and 10th grade

Data publikacji: 09 Feb 2017
Zakres stron: 133 - 141

Abstrakt

Abstract

The purpose of this paper is to follow “Climate change, risks and Natural Resources“ in the curriculum of Geography of Bulgaria and the world in 9th and 10th grade and to interpret some didactic aspects.

Analysis of key themes, concepts and categories related to the environment, events and approaches to environmental protection and the environmentally sound development of sectors of the economy is didikticheski targeted. Considering the emergence and development of geo-ecological issues, their scope and their importance to the environment, systematize some species and some approaches to solving them.

Geography education in grade 9 and 10 involves acquiring knowledge, developing skills and composing behaviors of objective perception and assessment of the reality of globed, regional and local aspect.

The emerging consumer and individualistic culture snowballing globalization, are increasingly occurring global warming, declining biodiversity form new realities which education must respond appropriately.

The objective, consistency, accessibility and relevance in real terms are meaningful, logical accents. Whether and how reproduced in the study of Geography of Bulgaria and the world is the subject of research study in this report.

Geoecological structuring of topics, concepts and categories can be done in different signs. In terms of their scope are local, national or regional, and global. Matter and interdisciplinary approach, which is to reveal the unity of the “man-society-nature” to clarify the complexity of their character with a view to forming a harmonious personality with high Geoecological consciousness and culture, and the activities carried out in their study.

20 Artykułów
access type Otwarty dostęp

Editorial Note: Where Science Meets Art

Data publikacji: 09 Feb 2017
Zakres stron: 5 - 5

Abstrakt

access type Otwarty dostęp

Synthesis and properties of N-alkyl(phenyl)amido-O-methyl-1,2-alkadienephosphonates

Data publikacji: 09 Feb 2017
Zakres stron: 6 - 12

Abstrakt

Abstract

The synthesis of the titled compounds has been described. Their reactivity towards electrophilic and nucleophilic reagents has been investigated.

Słowa kluczowe

  • 1,2-alkadienephosphonates
  • 2,5-dihydro- 1,2-oxaphospholes
  • ⃞-ketophosphonates
access type Otwarty dostęp

Interaction of 1,2-Alkadienephosphonic thioesters with sulphenyl- and selenenylbromide

Data publikacji: 09 Feb 2017
Zakres stron: 13 - 18

Abstrakt

Abstract

The reactivity of thioesters of 1,2-alkadienephosphonic acids toward sidphenyl- and selenenyl bromides has been investigated.

Słowa kluczowe

  • 1,2-aikadienephosphonates
  • phenylsulphenyl bromide
  • phenylselenenyl bromide
access type Otwarty dostęp

Evolutions and equilibrium parameters of foam films from individual solutions of Bovine serum albumin, n-dodecyl-β-D-maltoside and from their mixed solutions

Data publikacji: 09 Feb 2017
Zakres stron: 19 - 28

Abstrakt

Abstract

The evolutions of thinning of films from individual solutions of BSA, C12G2 and from their mixed solutions with molar ratios 1:1, 1:7.5, 1:50 and 1:100 with pH = 4.9 were recorded by modified (with video camera) interferometric method. Based on them the stages through which the film goes from its formation to the equilibrium state were distinguished. It was shown that: (i) the difference between the kinetic of drainage of films stabilized by high and low molecular surfactants is drastic; (ii) only the change of the pH solution under or above isoelectric point strongly retards the film drainage; (iii) the transition of the kinetic of thinning of films from mixed solutions from a kinetic typical for high molecular substances towards a kinetic for low substances depends on the molar ratio between the components in the solution. From the picture of film corresponding to its equilibrium state the type of film was determined. From the analysis of this picture the equilibrium thickness and contact angle were calculated. It was found that the criterion for Newtonium black films (based on the values of film thickness and contact angle) is not directly applicable for films from protein solutions or mixed solutions with the participation of proteins.

Słowa kluczowe

  • Bovine Serum Albumin (BSA)
  • n-dodecyl - β -D maltoside (C12G2)
  • mixed BSA/ C12G2 solutions
  • film evolution
  • equilibrium thickness
  • contact angle.
access type Otwarty dostęp

Descriptor Fingerprints and Their Application to Red Wine Clustering and Discrimination

Data publikacji: 09 Feb 2017
Zakres stron: 29 - 33

Abstrakt

Abstract

The investigation was performed to test the potentials of the fingerprint clustering algorithm for a set of 1599 red wines in relation to some wine properties, comprised in the notion “wine quality”. We have obtained a distribution of the wines into different clusters as a result. Each cluster was composed of wine-objects with similar values of laboratory parameters and with a wine quality certificate. A correlation between the. quality of wines (a sensory taste factor) and the phisicochemical descriptors (laboratory analytical test results data) was observed and analyzed.

Słowa kluczowe

  • similarity search
  • descriptor fingerprints
  • red wine clustering
access type Otwarty dostęp

Experimental studies on equilibrium adsorption isosteres and determination of the thermodynamic quantities of polar media on alumina Al2O3

Data publikacji: 09 Feb 2017
Zakres stron: 34 - 45

Abstrakt

Abstract

The present work is a revieif of theoretical and experimental study on the adsorption performance of the adsorbent Alumina (Al2O3) used in the adsorption system. An experimental investigation on the equilibrium adsorption isosteres at low pressure (< 1 atm) of working pairs Al2O3/H2O and Al2O3/C2H6O2 is carried out. The isovolume measurement method is adopted in the test setup to directly measure the saturated vapor pressures of working pairs at vapor-liquid equilibrium (dG=0 and dμi=0). Quantity adsorbed is determined from pressure, volume and temperature using gas law. The isosteric heat of adsorption is calculated from the slope of the plot of lnP versus 1/T different amounts of adsorbate onto adsorbent as follows: 0,01 vol% Al2O3/H2O; 0,03 vol% Al2O3/H2O; 0,1 vol% Al2O3/H2O; 0,01 vol% Al2O3/C2H6O2; 0,03 vol% Al2O3/C2H6O2; 0,1 vol% Al2O3/C2H6O2. This study shows that adsorption working pair Al2O3 C2H6O2 has better adsorption performances than those of the A2O3/H2O. Surface acidity! is a most important property! far both adsorption and catalysis and therefore is examined structure of active sites of alumina surface. Thermodynamic parameters such as isosteric heat of adsorption, isosteric enthalpy and entropy of adsorption are critical design variables in estimating the performance and predicting the mechanism of an adsorption process and are also one of the basic requirements for the characterization and optimization of an adsorption process

Słowa kluczowe

  • heterogenous acid-base catalyzer
  • surface acidity
  • polar organic solvent
  • isosteric heat of adsorption
  • isosteric enthalpy and entropy of adsorption
access type Otwarty dostęp

Allelopathic activity of Nepeta nuda L. subsp. nuda water extracts

Data publikacji: 09 Feb 2017
Zakres stron: 46 - 51

Abstrakt

Abstract

Nepeta nuda subsp. nuda is a medicinal plant growing wild in Bulgaria. Different species of Nepeta genus have been reported to possess allelopathic potential. The present study was conducted to observe its phytotoxic effects on T. aestivum and C. sativus L. seeds in laboratory conditions. Nepeta water extracts (NWE) prepared from aerial parts of plants at concentrations 2, 4, 6, 8, 10, 12 and 14 g/l were tested. The rate of seed germination, the root and shoot length, fresh and dry weight of seedlings were observed after treatment with NWE. As a control served seeds treated with distilled water. Germination was not affected, but NWE showed deterioration in seedling growth. Roots were more affected than shoots. The fresh and dry weights were reduced upon treatment with the extracts tested. These negative effects were dose-dependent. The overall results indicate presence of water soluble allelochemicals in Nepeta nuda subsp. nuda.

Słowa kluczowe

  • Nepeta nuda subsp. nuda
  • allelopathy
  • root and shoot growth inhibition
  • fresh and dry weight
access type Otwarty dostęp

Covalent immobilization of rabbit-antiaflatoxin-antibodies onto the poly-acrylamideacrylonitrile as well as hybrid material UREASIL and developing an optical immunosensor

Data publikacji: 09 Feb 2017
Zakres stron: 52 - 56

Abstrakt

Abstract

The aim of this work is to describe a covalent immobilization of antibodies onto the poly- acrylamide-acrylonitrile or hybrid material UREASIL and creation of optical immunosensor for determination of aflatoxin Bl. For this purpose, mouse-anti-aflatoxin B1 antibodies with oxidized carbohydrate moieties were covalently immobilized on the membranes of polyacrylamide- polyacrylonitrile copolymer, as well as the hybrid material UREASIL. To determine the affinity> binding of the immobilized antibody with afatoxin Bl was used "sandwich" method. Associated with the immobilized antibody sought ingredients interact with a surplus of secondary’ signal antibodies. The described method has been developed as a model system, which can easily be applied for the determination of aflatoxins in samples of different origin. To the best of our knowledge, this is the first study to show that in the establishment of biosensor was used hybrid material UREASIL.

Słowa kluczowe

  • aflatoxin B1
  • immunosensor
  • optical Biosensor
  • immobilization
  • antibody
access type Otwarty dostęp

Mazer’s theory application in Bi4Ge3O12:V

Data publikacji: 09 Feb 2017
Zakres stron: 57 - 60

Abstrakt

Abstract

The recent development of coherent light amplifiers and oscillators, now generally referred to as optical masers “or lasers,” has made feasible a host of new uses and applications of electromagnetic wave energy in the optical portion of the spectrum. Furthermore, the high degree of monochromaticity obtainable from an optical maser makes it a useful tool for spectroscopic investigations as well as for stimulating various types of chemical and physical reactions. The effect of vanadium doping transforms Bi4Ge3O12 single crystals into optical maser. This result can be observed after thermoluminescence at 556 nm.

Słowa kluczowe

  • optical maser
  • vanadium doping
  • Shrödinger’s time-dependent equation
access type Otwarty dostęp

Electronic setup for fluorescence emission measurements and long-time constant-temperature maintenance of Single-Walled Carbon Nano-Tubes in water solutions

Data publikacji: 09 Feb 2017
Zakres stron: 61 - 69

Abstrakt

Abstract

In our previous research we have observed that the fluorescence emission from water solutions of Single-Walled Carbon Nano-Tubes (SWCNT), excited by a laser with a wavelength of 830nm, diminishes with the time. We have already proved that such a fading is a function of the storage time and the storage temperature. In order to study the emission of the SWCNT as a function of these two parameters we have designed and realized a special measurement compartment with a cuvette holder where the SWCNT solutions can be measured and stored at a fixed constant temperature for periods of time as long as several weeks. To maintain the measurement setup under a constant temperature we have designed special experimental setup based on two Peltier cells with electronic temperature control.

Słowa kluczowe

  • SWCNT
  • Single Walled Carbon Nanotubes
  • fluorescence
  • Peltier cell
access type Otwarty dostęp

Fish Lipids as a Valuable Source of Polyunsaturated Fatty Acids

Data publikacji: 09 Feb 2017
Zakres stron: 70 - 75

Abstrakt

Abstract

This article presents information about omega-3 (h-3) and omega-6 (n-6) polyunsaturated fatty acid (PUFA) contents in a broad range of commercially important fish species available on Bulgarian fish markets. The aim is to raise consumers’ awareness and encourage them to eat fish. Fish species from the Black Sea coast have relatively high proportion of n-3 PUFAs, of which more than 80% is by EPf (eicosapentaenoic acid, C 20:5 n-3) and DHA (docosahexaenoic acid, C 22:6 n-3). Extensive epidemiological studies show that fish consumption is inversely associated with the incidence of cardiovascular diseases (CVD), stroke and the functioning of the brain. About 0.5 g of omega-3 (EPA+DHA) a day or two savings of oily fish a week are required to reduce the risk of death from CVD. PUFAs needs should be satisfied not only with food additives but with fish lipids containing food.

Słowa kluczowe

  • omega-3
  • omega-6
  • Black Sea fish
  • health benefits
access type Otwarty dostęp

Nutritional status in short-term overtraining boxers

Data publikacji: 09 Feb 2017
Zakres stron: 76 - 83

Abstrakt

Abstract

The diet is essential to the recovery process in athletes, especially those undergoing intensive training. The continuous imbalance between loading and recovery leads to development of overtraining syndrome. The purpose of this study was to establish the changes in the nutritional status of short-term overtrained athletes. Twelve boxers from the team of National Spoils Academy Sofia, Bulgaria during their preparation for the National Championship 2016 were studied. The measurements were conducted three times.in the beginning of preparation (T1), 22 days later (2) and 10 days after (32 days after first measurement), in the beginning of the recovery period, one week prior the competition (T3).The measurements included basic anthropometric data, overtraining questionnaire RESTO-Sport and nutrition questionnaire, plasma concentration of testosterone and cortisol.On the data of dietary survey the percent proportion and the amount of daily consumed proteins, fats and carbohydrates were defined and the energy intake of the tested athletes was calculated. According to the RESTO-Sport a significant decrease in the ratio stress/recovery was observed in the period with the heaviest training load T2, and an increase was estimated in the pre­competition recovery period T3. It was found a typical for the overtraining syndrome decrease in the concentration of testosterone and the ratio of testosterone/cortisol in T3. In some respondents a reduction in carbohydrates and proteins intake was observed in T2 and especially in T3, which correlates with the hormonal changes. In this work the diet changes was discussed as a possible consequence and/or a cause of the overtraining syndrome.

Słowa kluczowe

  • cortisol
  • nutrition
  • overtraining
  • sports
  • testosterone
access type Otwarty dostęp

Diagnosis of the socionic temperament of personality and creating a psychological portrait of the Western European SPA and wellness tourists in Bulgaria

Data publikacji: 09 Feb 2017
Zakres stron: 84 - 88

Abstrakt

Abstract

Human personality is a set of psychological characteristics that distinguishes it from others. However people can be classified as congenital personality types, interactions that are precisely defined. The aim of this article is to characterize the socionic temperament and psychological profile of the spa and wellness tourists in Bulgaria. The study is based on a survey of 460 tourists who visited Bulgarian spa centers in the summer and autumn of 2015.

Słowa kluczowe

  • spa and wellness
  • western European tourists
  • socionic temperament
  • psychological profile
access type Otwarty dostęp

Morphostructure of the Sakar and Strandzha Mountains

Data publikacji: 09 Feb 2017
Zakres stron: 89 - 93

Abstrakt

Abstract

The Sakar and Strandzha Mountains are disposed in the South-East end of the Balkan Peninsula (on the both sides of the Bulgarian-Turkish boundary). They belong to the southeastern margin of the Bulgarian continental microplate. They are limit from North Thracian morphostructural zone to the North, the East Thracian morphostructural zone to the South and the Rhodopean morphostructural zone to the West. The observed mountain territory builds the Sakar-Strandzha morphostructural zone. It is divided by Sakar Dervent and Strandzha morphostructural areas. Every of them include morphostructural regions. They are composed by numerous Late Pleistocene-Holocene dome-like morphostructures. The relics from the Post Early Pleistocene concentric morphostructures are distributed in the entire zone. They were determined some archer and concentric Holocene mountain morphostructures.

The regional seismic activity (during the last 50 years) outlines three parts of the Sakar-Strandzha morphostructural zone. The western one - the Sakar part is moderate seismic active. The centred - Dervent part is practically seismic „calm“. The eastern one- Strandzha part show a very intensive seismicity. It can by given right in a future (after the necessary investigations) to divide the zone in three areas.

Słowa kluczowe

  • morphostructural writs
  • morphostructural generations
  • mountain morphostructures
access type Otwarty dostęp

Geomorphology of outflow part Batova river valley

Data publikacji: 09 Feb 2017
Zakres stron: 94 - 99

Abstrakt

Abstract

Firths are geomoiphological and hydrological sites typical for flat, neutral coast of no tidal sea basins. There in the greatest extend is preserved the geological column of the correlative Pleistocene- Holocene sediments. They make possible to reveal the Quaternary evolution of the contact zone „land-sea“. Firths are one of the most reliable indicators for the Quaternary Earth crust movements.

Along the Black Sea coast most widely are developed the firths in the north - west and the west periphery, where they form a classic firth type coast.

This report examines the results of complex studies of Batova river firth, located (developed) on the North Bulgarian Black Sea coast.

Słowa kluczowe

  • firth (liman)
  • coastline
  • neutral type of coast
  • Quaternary movements
access type Otwarty dostęp

The Impact of Environmental Factors on the Amount of Nitrates and Nitrites in Different Types of Soils and Ways of Their Utilization

Data publikacji: 09 Feb 2017
Zakres stron: 100 - 105

Abstrakt

Abstract

Despite the last decade considerable advances in the study of nitrate and nitrite pollution of soil, there are still some gaps in research related to neglecting or ignoring the role of soil in the food chain and its effects on upper trophic units. The article presents the results of a study on the impact of air and soil humidity and temperature, as well as soil type and utilization on the amount of nitrates and nitrites in the soil solution at the end of vegetation period. It was proved that statistically significant impact on the amounts of residual nitrate and nitrite ions was caused by the temperature and moisture of soil, its type, and the specific properties of the crops grown.

Słowa kluczowe

  • nitrates
  • nitrites
  • pollution of soils
  • soil types
access type Otwarty dostęp

The regional approach and regional studies method in the process of geography teaching

Data publikacji: 09 Feb 2017
Zakres stron: 106 - 117

Abstrakt

Abstract

We define the regional approach as a manner of relations among the global trends of development of the “Society-man-nature” system and the local differentiating level of knowledge. Conditionally, interactions interlace under the influence of the character of Geography as a science, education, approaches, goals and teaching methods.

Global, national and local development differentiates in three concentric circles at the level of knowledge. It is determined as a conception of modern, complex and effective mechanism for young people, through which knowledge develops in regional historical and cultural perspective; self-consciousness for socio-economic and cultural integration is formed as a part of the. historical-geographical image of the native land. This way an attitude to the. native land is formed as a connecting construct between patriotism to the motherland and the same in global aspect.

The possibility for integration and cooperation of the educative geographical content with all the local historical-geographical, regional, profession orientating, artistic, municipal and district institutions, is outlined.

Contemporary geographical education appears to be a powerful and indispensable mechanism for organization of human sciences, while the regional approach and the application of the regional studies method stimulate and motivate the development and realization of optimal capacities for direct connection with the local structures and environments.

Słowa kluczowe

  • geography
  • teaching
  • education
  • methods
  • didactics
  • approach
access type Otwarty dostęp

Implementing Interactive Teaching Methods for 9th Grade Organic Chemistry Classes

Data publikacji: 09 Feb 2017
Zakres stron: 118 - 123

Abstrakt

Abstract

One of the main challenges facing the current educational system is creating conditions suitable for academic skill development that allow students to navigate and adapt to today’s modern society, such as locating relevant information quickly as well as effectively utilizing innovations. We can achieve this objective by using interactive teaching methods. These methods take into account the contemporary issues and changing priorities - from the general content building for the courses to independent, student-centered cognitive activities.

The propose of this paper is to present tested and proven interactive methods for Grade 9Organic Chemistry classes. These methods significantly improve the quality of teaching and the students’ interest in the subject.

Słowa kluczowe

  • teacher training
  • organic chemistry
  • interactive methods
access type Otwarty dostęp

Expectations of the Educational Reform of High School Geography

Data publikacji: 09 Feb 2017
Zakres stron: 124 - 132

Abstrakt

Abstract

The study is an attempt to present the latest developments in legislation for implementation of the reform in geographic education in secondary school. Through conducted survey has been taken into account the views and expectations of teachers of Geography and Economics in terms of the new law, a framework curriculum, State educational standards and curricula. Expectations of educational reform are formulated as positive and negative sides. Referred to a recommendation for overcoming some of the problems were identified.

Słowa kluczowe

  • educational reform
  • school geographical education
access type Otwarty dostęp

Climate Change, Risks and Natural Resources didactic issues of educational content geography of Bulgaria and the world in 9th and 10th grade

Data publikacji: 09 Feb 2017
Zakres stron: 133 - 141

Abstrakt

Abstract

The purpose of this paper is to follow “Climate change, risks and Natural Resources“ in the curriculum of Geography of Bulgaria and the world in 9th and 10th grade and to interpret some didactic aspects.

Analysis of key themes, concepts and categories related to the environment, events and approaches to environmental protection and the environmentally sound development of sectors of the economy is didikticheski targeted. Considering the emergence and development of geo-ecological issues, their scope and their importance to the environment, systematize some species and some approaches to solving them.

Geography education in grade 9 and 10 involves acquiring knowledge, developing skills and composing behaviors of objective perception and assessment of the reality of globed, regional and local aspect.

The emerging consumer and individualistic culture snowballing globalization, are increasingly occurring global warming, declining biodiversity form new realities which education must respond appropriately.

The objective, consistency, accessibility and relevance in real terms are meaningful, logical accents. Whether and how reproduced in the study of Geography of Bulgaria and the world is the subject of research study in this report.

Geoecological structuring of topics, concepts and categories can be done in different signs. In terms of their scope are local, national or regional, and global. Matter and interdisciplinary approach, which is to reveal the unity of the “man-society-nature” to clarify the complexity of their character with a view to forming a harmonious personality with high Geoecological consciousness and culture, and the activities carried out in their study.

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