Evaluation of Contemporary Environmental Condition of River Basins in Southern Pre-Caspian Areas of Azerbaijan

Southern Pre-Caspian areas of the Republic of Azerbaijan have favorable geographical position as well as natural and climatic condition for dwelling, development of settlements, and industrial activity. Most areas have fertile soils and attractive landscapes. These factors facilitate human distribution in the researched area and therefore, the area is highly populated. Population are engaged mainly in areas such as farming, namely production of tea, vine, cereals, vegetable, different fruits, including citrus plants, production of foods, and also cattle- and sheep-breeding. As a result, the coastal zone and rivers experience high anthropogenic influence. This article deals with the study of anthropogenic pollution of highly-settled river basins and valleys as well as evaluation of changes going by quality of river waters in southern Pre-Caspian areas of Azerbaijan

Influence of dispersing additive on asphaltenes aggregation in model system

The work is devoted to investigation of the dispersing additive influence on asphaltenes aggregation in the asphaltenes-toluene-heptane model system by photon correlation spectroscopy method. The experimental relationship between the onset point of asphaltenes and their concentration in toluene has been obtained. The influence of model system composition on asphaltenes aggregation has been researched. The estimation of aggregative and sedimentation stability of asphaltenes in model system and system with addition of dispersing additive has been given

STRUCTURAL AND TECHNOLOGICAL PARAMETERS AFFECTING THE BIPOLAR STATIC INDUCTION TRANSISTOR (BSIT ) RESISTANCE

Aim. The aim of the study is to determine the impact of structural and technological parameters on the resistance of the bipolar static induction transistor.Methods. The paper provides a comparative analysis of the advantages of bipolar static induction transistor compared to the bipolar power transistors, MOSFETs and insulated-gate bipolar transistor (IGBT). Considered are structural and technological parameters that influence the resistance of BSIT-transistor.Result. As a result of experimental study on silicon substrates were formed test prototypes of BSIT transistor structure, are presented calculation and experimental works. Obtained are the resistance dependencies of the transistor cell on the thickness of the epitaxial film; the resistance dependencies of BSIT transistor cell on the effective gate length for different values of the impurity concentration in the epitaxial film; dependencies resistance of the transistor cell on the gate length at different values of the epitaxial film thickness; the resistance dependencies of BSIT transistor cell on the distance between the mask for the p-region and the gate; dependencies on the multiplication the cell resistance by its area on the gate length.Conclusion. When increasing the gate length (Lk) and the mask length for the p-region (lp +) in the transistor structure, the resistance decreases and the dependence of multiplication of the cell resistance by its area Q on the gate length has this case the minimum

Interband electron Raman scattering in a quantum wire in a transverse magnetic field

Electron Raman scattering (ERS) is investigated in a parabolic semiconductor quantum wire in a transverse magnetic field neglecting by phonon-assisted transitions. The ERS cross-section is calculated as a function of a frequency shift and magnetic field. The process involves an interband electronic transition and an intraband transition between quantized subbands. We analyze the differential cross-section for different scattering configurations. We study selection rules for the processes. Some singularities in the Raman spectra are found and interpreted. The scattering spectrum shows density-of-states peaks and interband matrix elements maximums and a strong resonance when scattered frequency equals to the "hybrid" frequency or confinement frequency depending on the light polarization. Numerical results are presented for a GaAs/AlGaAs quantum wire.Comment: 8 pages, 5 figure

Применение экстракорпоральных систем протезирования функций печени при острой декомпенсированной печеночной недостаточности

The aim of the study: to evaluate the efficacy of extracorporeal liver support systems in patients with acute liver failure of various etiologies.Material and methods. The study included 117 patients with acute liver failure of various etiologies. The main group consisted of 71 patients who received complex intensive therapy, including MARS-therapy and hemodiafiltration. The comparison group included 46 patients who received albumin dialysis (24 patients) and hemodiafiltration (22 patients) alone. The mean age of the patients was 34±5.6 years, the majority (56.4%) were men. Dynamic assessment of patients' severity was performed using Sequential Organ Failure Assessment (SOFA) and Model for End-Stage Liver Disease (MELD) scales.Results. A more significant reduction of SOFA and MELD scores was noted as early as by day 10 of intensive therapy in the main group with sequential use of extracorporeal liver detoxification methods — to 2.7±0.2 vs. 8.3±0.5 points (P=0.021) on SOFA and to 16.7±0.4 vs. 23.4±1.4 points (P=0.023) MELD scales. The use of a comprehensive approach to extracorporeal detoxification in acute decompensated liver failure increased the regression rate of multiple organ failure from 51.2 to 74.6% and reduced mortality from 47.8 to 25.4% (χ2=6.266; df=1; P=0.013). At the same time, the cumulative proportion of survivors depending on the type of complication within 30 days was 88.4% in the main group and 69.0% in the comparison group (χ2=4.164; df=1; P=0.042).Conclusion. A comprehensive approach to extracorporeal detoxification is highly effective, providing a more significant reduction of SOFA and MELD scores, increasing the proportion of regression of multiple organ dysfunction and reducing mortality.Цель исследования: выявить эффективность систем экстракорпоральной поддержки печени у пациентов с острой печеночной недостаточностью различного генеза.Материал и методы. В исследование включили 117 пациентов с острой печеночной недостаточностью различного генеза. Основную группу составили 71 пациент, которые получали комплексную интенсивную терапию, включая применение MARS-терапии и гемодиафильтрацию. В группу сравнения включили 46 пациентов, которым применены изолированно альбуминовый диализ — 24 пациента и гемодиафильтрация — 22 пациента. Средний возраст пациентов составил 34±5,6 лет, большинство (56,4%) были мужчины. Динамическую оценку тяжести состояния пациентов проводили по оценочным шкалам Sequential Organ Failure Assessment (SOFA) и Model for End-Stage Liver Disease (MELD).Результаты. Более существенное снижение показателей по шкалам SOFA и MELD отмечено уже к 10 суткам интенсивной терапии в основной группе при последовательном использовании методов экстракорпоральной детоксикации печени по шкале SOFA — до 2,7±0,2 против 8,3±0,5 баллов (p=0,021) и MELD — до 16,7±0,4 против 23,4±1,4 баллов (p=0,023). Применение комплексного подхода к экстракорпоральной детоксикации при острой декомпенсированной печеночной недостаточности позволило увеличить долю регресса полиорганной недостаточности с 51,2 до 74,6%, сократить летальность с 47,8 до 25,4% (χ2=6,266; df=1; p=0,013). При этом кумулятивная доля выживших в зависимости от типа осложнения в сроки до 30 суток составила при 88,4% — в основной группе и 69,0% — в группе сравнения (χ2=4,164; df=1; p=0,042).Заключение. Комплексный подход к экстракорпоральной детоксикации имеет высокую эффективность, обеспечивая более существенное снижение баллов по шкалам SOFA и MELD, позволяет увеличить долю регресса полиорганной дисфункции и сократить летальность

MODELING OF THERMOELECTRIC SYSTEM FOR LOCAL THERMAL EFFECTS ON HUMAN FOREARM ZONE

In this paper we consider a model of the thermoelectric system for the thermal effect on the human forearm. The model is implemented on the basis of numerical solution of differentialequations of heat conduction for bodies of complex configuration. Two-dimensional and onedimensional graphs of the temperature change in different zones of the object of exposure aregiven

On a factorization of second order elliptic operators and applications

We show that given a nonvanishing particular solution of the equation (divpgrad+q)u=0 (1) the corresponding differential operator can be factorized into a product of two first order operators. The factorization allows us to reduce the equation (1) to a first order equation which in a two-dimensional case is the Vekua equation of a special form. Under quite general conditions on the coefficients p and q we obtain an algorithm which allows us to construct in explicit form the positive formal powers (solutions of the Vekua equation generalizing the usual powers of the variable z). This result means that under quite general conditions one can construct an infinite system of exact solutions of (1) explicitly, and moreover, at least when p and q are real valued this system will be complete in ker(divpgrad+q) in the sense that any solution of (1) in a simply connected domain can be represented as an infinite series of obtained exact solutions which converges uniformly on any compact subset of . Finally we give a similar factorization of the operator (divpgrad+q) in a multidimensional case and obtain a natural generalization of the Vekua equation which is related to second order operators in a similar way as its two-dimensional prototype does

Investigation of conduction band structure, electron scattering mechanisms and phase transitions in indium selenide by means of transport measurements under pressure

In this work we report on Hall effect, resistivity and thermopower measurements in n-type indium selenide at room temperature under either hydrostatic and quasi-hydrostatic pressure. Up to 40 kbar (= 4 GPa), the decrease of carrier concentration as the pressure increases is explained through the existence of a subsidiary minimum in the conduction band. This minimum shifts towards lower energies under pressure, with a pressure coefficient of about -105 meV/GPa, and its related impurity level traps electrons as it reaches the band gap and approaches the Fermi level. The pressure value at which the electron trapping starts is shown to depend on the electron concentration at ambient pressure and the dimensionality of the electron gas. At low pressures the electron mobility increases under pressure for both 3D and 2D electrons, the increase rate being higher for 2D electrons, which is shown to be coherent with previous scattering mechanisms models. The phase transition from the semiconductor layered phase to the metallic sodium cloride phase is observed as a drop in resistivity around 105 kbar, but above 40 kbar a sharp nonreversible increase of the carrier concentration is observed, which is attributed to the formation of donor defects as precursors of the phase transition.Comment: 18 pages, Latex, 10 postscript figure