Вимірювальна техніка та метрологія. – 2016. – Випуск 77

Permanent URI for this collectionhttps://ena.lpnu.ua/handle/ntb/39773

Міжвідомчий науково-технічний збірник

Вимірювальна техніка та метрологія : міжвідомчий науково-технічний збірник / Міністерство освіти і науки України ; відповідальний редактор Б. І. Стадник. – Львів : Видавництво Львівської політехніки, 2016. – Випуск 77. – 198 c. : іл.

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Антропогенна трансформація властивостей екотонів захисного типу на шляхах залізничного транспорту
(Видавництво Львівської політехніки, 2016) Обшта, Анатолій; Сорока, Ірина; Руда, Марія; Національний університет “Львівська політехніка”; Національний лісотехнічний університет України
Подано результати досліджень щодо формування екотонів захисного типу та створення інформаційно-аналітичної системи підтримки управлінських рішень для забезпечення рівня їх функціонування, який відповідає міжнародним стандартам, що регламентують сучасні вимоги до систем захисту довкілля. Представлены результаты исследований по формированию экотонов защитного типа и созданию информационно-аналитической системы поддержки управленческих решений для обеспечения уровня их функционирования, который соответствует международным стандартам, регламентирующим современные требования к системам защиты окружающей среды. The influence of rail transport on the environment creates many problems as it includes violation of the stability of natural landscapes transport infrastructure through the development of erosion and landslides; air pollution by exhaust gases; permanent increase in oil pollution of earth, lead, blowing products and shedding of bulk cargo (coal, ore, cement). Along with the benefits offered by the railway transport, there arise accute lssues of environmental safety during its use, which is caused by its negative and even destructive impacts on the environment. Sanitation methods provide for mandatory monitoring of the environment. The object of study is the quality of protective ecotones of the Lviv Railway. The forest shelterbelts, investigated in the railway sections Lviv – Sambir, Lviv – Ivano-Frankivsk, Lviv – Rava-Ruska, Lviv – Kovel, Lviv – Krasne, Lviv – Mostyska, Lviv – Stryi, Stryi – Mukachevo, and Ivano-Frankivsk – Chernivtsi, are mainly double-row ones (except natural forests growing along the railway lines) of 200 m in width on both sides of the track. The species composition of the stands is characterized by its diversity depending on forest site type. The trees are often top-drying, from the side of the railway tracks they have windfirm and dense crowns. The undergrowth is suppressed by snow drifts. The protective ecotones are characterized by the distribution of precipitation, soil moisture, and productivity of the adjacent agricultural lands. As a result, a kind of parademe system is formed along the Lviv Railway lines,consortium, that significantly differs from natural one due to overlapping ecological niches. This consortium has much in common with conserved (ecological) corridors because the integrated assessement shows increasing species diversity of agrosystem flora by 17 – 73%, entomofauna – by 27 – 62.5%, zoofauna – by a factor of 2.7 times. According to the field studies, we have classified the protective ecotones of the Lviv Railway by characteristics of profile, i.e. the structure and composition of plantations by their origin. Full-profile protective ecotones are plantations where the structure of shelterbelts (ecotones) can be clearly seen, they can be found in all sections of the Lviv Railway where the protective forest plantations were artificially created. Predominantly, they consist of one or, less common, three strips. Ecotone is formed at the boundary of two different anthropogenic tracts in a railway precinct. Across the study sections of the railway lines, only mixed stands were observed, no pure stands were found. A field study of ties between morphology and function of cumulative and ecosystem engineer; statistical methods investigated the potential protective effect of ecotones Lviv railway. The complex and differentiation characteristics of cumulative function of protective ecotones depends on the morphology and composition of forest communities –edificator. In the structure of vegetation in the consortium of protective ecotones, there is a significant amount of synanthropic and acclimatized species. Active processes are currently observed of human-induced changes in primary stands to form natural-anthropogenic stands in a wider array. The aggregate of protective ecotones at the Lviv Railway is functioning as a single system or forest reclamation complex that serves as the ecological framework where elements and subsystems interact providing a synergistic effect. Proceeding from the necessity of shifting to landscape-ecological principles of management and ensuring the maximum possible protective effect, the creation of a system of protective ecotones is one of the most innovative ways of ensuring ecosystem sustainability, in particular, enhancing their buffering capacity due to partial renewal of forest ecosystems as an integral component of natural landscape, which will provide for environmental safety on railway lines using only natural mechanisms of environmental protection. Method of investigation of environmental safety in railway transport is of great polyfunctional importance as this enables, on the basis of the landscape-ecological methods, to form consortiums of protective ecotones that will provide the maximum spatial-temporal efficacy.
Дослідження термометричного матеріалу HF1-хErxNiSn
(Видавництво Львівської політехніки, 2016) Крайовський, Володимир; Національний університет “Львівська політехніка”
Досліджено енергетичні, кінетичні та магнітні характеристики термометричного матеріалу Hf1-xErxNiSn у діапазонах T = 80÷400 K, x=0÷0.10 за напруженості магнітного поля H £10 кГс. Показано, що характеристики Hf1-xErxNiSn чутливі до зміни температури і він може бути основою для виготовлення чутливих елементів термоперетворювачів. Исследованы энергетические, кинетические и магнитные характеристики термометрического материала Hf1-xErxNiSn в диапазонах: T = 80÷400 K, x=0÷0.10 при напряженности магнитного поля H £ 10 кГс. Показано, что характеристики Hf1-xErxNiSn чувствительны к изменениям температуры и он может быть основой для изготовления чувствительных элементов термопреобразователей. The electron energy state, magnetic and transport characteristics of of thermometric materials Hf1-xErxNiSn were investigated in the T = 80÷400 K temperature range and at charge carriers concentration from x=01÷0.10 and H £ 10 kGs. The material Hf1-xErxNiSn is sensitive to the temperature change and could be used as the basis for the sensitive thermoelectric devices. We investigated the crystal structure, electron density of states (DOS) and the kinetic and energy characteristics of n-HfNiSn heavily doped with the Er impurity. Samples were synthesized at the laboratory of the Institute of Physical Chemistry, Vienna University. The Hf1-xErxNiSn crystal-lattice periods were determined by X-ray analysis with the use of the Full-prof software. We employed a data array obtained by the powder method using a Guinier-Huber image plate system. The chemical and phase compositions of the samples were determined using a Ziess Supra 55VP scanning electron microscope and an EMPA energy dispersive X-ray analyzer. The electronic structure was calculated by the Korringa–Kohn–Rostoker (KKR) technique in the coherent potential approximation (CPA) and local density approximation (LDA), as well as the full-potential linearized plane wave (FP-LAPW) method within density functional theory (DFT). In the calculations, we used experimental values of the lattice constant on a k grid 10×10×10 in size and the Moruzzi–Janak–Williams exchange-correlation potential parametrization. The width of the contoured energy window was 16 eV. The number of energy values for DOS calculations was 1000. To predict the behavior of the Fermi level, band gap, and electrokinetic characteristics of n-HfNiSn doped with Eratoms, the electron density distribution (DOS) was calculated. The calculated results pretending to be adequate to experimental studies should account for complete information on the semiconductor’s crystalline structure. To obtain more accurate results, we calculated the DOS for almost all possible cases of the mutual substitution of atoms at sites of the HfNiSn unit cell. Shows the result most consistent with experimental data. It was found that the disordered structure (Hf1-xNix)NiSn, x = 0.01, of the HfNiSn compound is most probable. We note that the same result was obtained from structural studies of HfNiSn. The partial (to 1 at %) substitution of Hf atoms with Ni atoms generates donor-type structural defects in the crystal, and the Fermi level is in the band gap which becomes narrower. It was also found that the minimum in the dependence of variations in the DOS at the Fermi level (DOSF(x)) for the disordered structure (Hf1-xNix)NiSn of the HfNiSn compound corresponds to the (Hf0.99Ni0.01)NiSn composition. In this semiconductor model, the Fermi level is in the band gap which is εg ≈ 282 meV. The same question arises when analyzing the behavior of the dependences (x) and (x) in Hf1-xErxNiSn. For example, the (x) variation in the concentration range 0.02 ≤ x ≤ 0.10 shows that the modulation amplitude of the continuous energy bands of Hf1-xErxNiSn HDCSs increases. Indeed, the activation energies (x) increase from (x = 0.05) = 38.3 meV to (x) (x = 0.07) = 59.2 meV. As we already noted, such behavior is possible only when compensating electrons appear in the p-type semiconductor due to the ionization of donors whose appearance was not initially assumed. In Hf1-xErxNiSn samples, x > 0.05, the decrease in (x) indicates a decrease in the modulation amplitude of the continuous energy bands, which is possible only when the degree of compensation of Hf1-xErxNiSn decreases due to a decrease or termination of the generation of donor-type structural defects. Thus, the initial assumption that n-ZrNiSn doping with Er atoms by substituting Hf atoms is accompanied by the generation of only donor-type structural defects in the crystal does not allow consistent explanation of the behavior of the energy characteristics of Hf1-xErxNiSn HDCS. The variations in the activation energy of hopping conduction (x) and the modulation amplitude of the continuous energy bands (x) unambiguously prove the existence of a donor source in Hf1-xErxNiSn. Further, we will identify the possible mechanism for the appearance of donors. The series of studies on the crystalline structure, energy spectrum, and electro-kinetic parameters of the n-HfNiSn intermetallic semiconductor heavily doped with the Er impurity allowed determination of the variation in the degree of compensation of the semiconductor due to the generation of both structural defects of donor nature during the substitution of Hf atoms with Er atoms and defects of donor nature during the partial substitution of Ni sites with Snatoms. The n-HfNiSn crystalline structure is disordered, and the Hf site can be occupied by Ni to ~1 at %, which generates structural defects of donor nature in the semiconductor and explains the mechanism of its “a priori doping with donors”. The mechanism of the degree of compensation of the semiconductor as the result of the crystal structure transformation during doping, leading to the generation of structural defects of donor nature was established. The results of the electronic structure calculation are in agreement with experimental data and the Hf1-xErxNiSn semiconductor is a promising thermoelectric material. The results are discussed in the framework of the heavily doped and compensated semiconductor model by Shklovsky–Efros.