Репозиториум на ХТМУ-София

Добре дошли в официалния електронен репозиториум на ХТМУ-София.

Изследователското хранилище на университета е с отворен достъп и изследванията и научните резултати, включени тук, са избрани и депозирани от библиотеката, отделните университетски звена и изследователски центрове в ХТМУ-София.

Хранилището съдържа:

  • електронни дисертации и научни публикации, включително статии, доклади от конференции, работни документи и някои изследователски монографии;
  • материали и публикации, свързани с университета при изпълнение на научни проекти.

Предоставя се пълно текстово съдържание за всички научни публикации в хранилището и, когато е възможно, за електронни дисертации.

Отвореният достъп осигурява възможно най-широкото разпространение и въздействие на постигнатите резултати на научните колективи в ХТМУ и допринася за нарастващия обем от научноизследователска литература, свободно достъпна онлайн.

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SYNTHESIS AND PHOTOSTABILITY OF SOME NEW 1,8-NAPHTHALIMIDE DERIVATIVES AS COLOUR MONOMERS FOR FLUORESCENT POLYMERS
(2025-09-03) Miladinova P.M.
Two new polymerizable 1,8-naphthalimide fluorophores containing a residue of a glycine or β-alanine in C-4 position of the naphthalimide ring have been synthesized. Their copolymers with methyl methacrylate were obtained. The colour coordinates of the prepared polymer have been determined. The photostability of the dyes and copolymers in dimethylformamide has been investigated and an increase in the photostability of dyes included in polymer with about 25-30 % was observed. The photostability of the polymer films obtained with copolymers and polymethyl methacrylate dyed “in mass” with the synthesized dyes has been determined by a change of colour coordinates and reflectance during the radiation with UV light. Results obtained lead to the conclusion that the dyes have good photostability and can be applied both as fluorescent dyes for dyeing of polymer materials “in mass” and as colour fluorescent monomers for obtaining of fluorescent polymers.
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FEASIBILITY STUDY INTO THE POSSIBILITY OF MANGANESE ORE ENRICHMENT WASTE USE FOR SORBENT MATERIAL DEVELOPMENT
(2026-01-01) Kalymbet A.; Kubekova S.; Kapralova V.; Lavrova S.
This study explores the synthesis of sorption-active phosphate materials from manganese ore enrichment tailings of the Zhairem deposit. The initial tailings, predominantly composed of calcite (76.4 %), quartz (16.4 %), and braunite, were characterized by XRD and EPMA. Acid-thermal treatment with phosphoric acid followed by calcination at 200-800°C yielded calcium - manganese phosphate materials. Phase transformations were monitored via XRD, showing formation of crystalline phosphates at 200-600°C and a glassy phase at 800°C. The product synthesized at 600°C demonstrated the lowest water solubility (9.91 %), highest pore volume (0.175 cm3 g-1), and optimal sorption capacity for Ni2+ (0.2934 mg-eq g-1), which increased to 0.4697 mg-eq g-1 after 0.4 wt. % of HCl activation. The enhanced performance is attributed to the formation of low-solubility polyphosphates and well-developed porous structures. SEM confirmed porous morphology at 600°C and denser, glassy structure at 800°C. The synthesized material showed no toxic elements such as Pb, Cd, or As, making it suitable for environmental applications. The findings indicate that Zhairem tailings are a promising raw material for producing effective sorbents for heavy metal removal, especially after acid activation. The optimal product is the calcium-manganese phosphate synthesized at 600°C.
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Modelling and numerical simulation of fire in a coffee storage hall
(2021-11-22) Krumov K.; Penkova N.; Mladenov B.; Stoyanov Y.
An approach for modelling of fire in halls at solid materials burning, based on gas phase combustion models in ANSYS/CFX, is proposed. The models are suitable for quick prediction of the flue gases distribution and thermal loads on the building envelopes at a design stage. They was applied for numerical simulation of such processes in a coffee storage hall at different fire positions and forced anti-smoke ventilation. The thermal, fluid flow and concentration field were obtained at the modelled scenarios. Maximal thermal loads on the building envelopes are established at the case of fire near their non-streamlined parts.
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Modelling and numerical simulation of the heat transfer and natural ventilation in storage halls
(2020-11-18) Penkova N.; Krumov K.; Mladenov B.; Stoyanov Y.
An algorithm for modelling of the heat transfer in storage halls at different combinations of open doors and smoke vents is developed. The models allow numerical simulations of velocity, pressure and temperature fields in the halls in cases of transient and steady state conditions, taking into account the indoor buoyancy, heat sources, heat transfer through the building envelopes and outdoor wind pressures. The models are solved numerically via finite volume method in order to estimate the necessity of additional heating at a design stage of a courier logistic storage hall, situated in the temperate climate zone, at the hardest winter conditions of the region. Recommendations about the organization of the heating and the cargo input are done based on the analyses of the fluid flow and thermal fields at the modelled scenarios.
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Performance of diffusion absorption refrigerators at variable power input
(2024-01-01) Stoyanov Y.; Penkova N.; Krumov K.
Absorption refrigerators have been used in recent decades for utilization of waste or solar energy to produce heat or cold for industrial purposes or to condition the microclimate in buildings. Although these units are designed at nominal power input in the generator, they can also operate at variable parameters of the heat source, which is possible in the real situations. An experimental determination of the operating range and the performance of a diffusion absorption refrigerator at heat pump and refrigeration mode were carried out in the present study. The results are useful for predicting the efficiency and the effectiveness of such systems at variable heat source capacities.