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es effets synergiques antimicrobiens et antioxydants du café (Coffea spp.) et du galanga (Alpinia galanga) : de l’usage traditionnel à la preuve scientifique
(2026) Chohra ferielle; Bouderwa fedwa; Hamed djahira
This study aims to evaluate the antioxidant, antimicrobial, and synergistic effects of
methanolic extracts from Coffea arabica and Alpinia galanga in order to scientifically
validate their traditional use. The extracts were obtained by maceration in a methanol/water
mixture (80:20) and subsequently characterized in terms of extraction yield, phenolic
composition, and biological activities. Extraction yields were 5.90% for C. arabica and 1.16%
for A. galanga. Phytochemical analysis revealed high levels of total polyphenols (233.07 mg
GAE/g for C. arabica and 383.84 mg GAE/g for A. galanga) and flavonoids (16.36 ± 3.85 mg
QE/g and 50.90 mg QE/g, respectively). Antioxidant activity assessed using the DPPH assay,
demonstrated significant radical scavenging capacity, with IC₅₀ values of 372.54 µg/mL for C.
arabica and 72.21 ± 1.78 µg/mL for A. galanga. Antimicrobial activity was evaluated using
the agar well diffusion method and determination of minimum inhibitory concentration (MIC)
against several pathogenic strains, including Staphylococcus aureus, Escherichia coli,
Pseudomonas aeruginosa, Bacillus cereus, and Candida albicans. The results showed notable
inhibitory activity, with inhibition zones reaching up to 25 mm for A. galanga and MIC
values varying depending on the strain. The synergistic effect, evaluated using the
checkerboard method, revealed total synergy (FICI ≤ 0.5) against certain strains, particularly
Klebsiella pneumoniae, as well as partial synergy or antagonism depending on the
microorganism. The combination of extracts significantly reduced MIC values. In conclusion,
these extracts exhibit promising biological properties and a significant synergistic potential
for pharmaceutical, food, and cosmetic applications.
Thermal optimization of hollow clay brick integrated with phase change materials
(2026) ZEHOUANI Zahra Assala; NEHARI Taieb; BOUNIF Abdelhamid
Lightweight construction materials are increasingly adopted in high-rise and super-
high-rise buildings due to their structural efficiency, ease of construction, and reduced
structural mass. However, the extensive use of such materials is often associated with low
thermal inertia, which adversely affects the thermal performance of building envelopes. The
reduced capacity to store and release heat leads to pronounced indoor temperature fluctuations,
increased peak cooling and heating demands, and a consequent deterioration of indoor thermal
comfort, especially in regions with extreme climatic conditions. In hot-dry climates, where
buildings are subjected to high solar radiation and large diurnal temperature variations, the
limitations of lightweight walls become even more critical. Under these conditions,
conventional lightweight building envelopes exhibit limited ability to attenuate heat transfer
and delay thermal peaks, resulting in elevated reliance on mechanical air-conditioning and
heating systems. This increased dependency not only raises energy consumption but also
contributes to higher operational costs and environmental impacts. To overcome these
challenges, the integration of phase change materials (PCMs) into building components has
emerged as a promising passive thermal regulation strategy. When incorporated into building
bricks, PCMs significantly enhance the thermal energy storage capacity of lightweight walls,
thereby improving the thermal inertia of the wall system.
Within this context, the present research investigates the thermal optimization of
lightweight hollow clay brick walls through the integration of PCMs under real climatic
conditions representative of hot-dry regions. A novel brick configuration incorporating two
different PCMs in a double-layer arrangement is proposed to enhance thermal energy storage
and improve dynamic thermal performance. The study adopts a transient numerical
methodology based on Computational Fluid Dynamics (CFD), incorporating phase-change
heat transfer models developed and validated using ANSYS Fluent. The thermal behavior of
the proposed double-PCM layer brick is systematically analyzed and compared with
conventional air-filled bricks and single-PCM layer configurations. Key performance
indicators, including indoor temperature evolution, heat flux, decrement factor, and time lag,
are used to quantify thermal performance improvements. The results demonstrate that the
double-PCM layer configuration significantly outperforms conventional and single-PCM
solutions by reducing peak indoor temperatures, attenuating indoor heat flux, and enhancing
time lag, thereby improving indoor thermal comfort and reducing cooling energy demand.
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Furthermore, a comprehensive parametric investigation is conducted to assess the influence of
PCM layer thickness and positioning on thermal performance. The findings indicate that
positioning the PCM with a higher melting temperature on the exterior side and the PCM with
a lower melting temperature on the interior side, with equal layer thicknesses, yields the
optimal thermal response. This configuration maximizes heat storage efficiency and effectively
shifts thermal loads away from peak outdoor temperature periods.
Overall, this thesis provides a detailed numerical framework and practical design
guidelines for the integration of multi-layer PCM systems into lightweight building envelopes.
The outcomes contribute to the development of energy-efficient and climate-responsive
building materials, offering effective solutions for reducing cooling energy consumption and
improving thermal comfort in buildings located in hot-dry climatic zones.
العلاج النسقي اﻷسري
(جامعة عين تموشنت بلحاج بوشعيب, 2026) قلعي, تسورية أمال
TRAVAUX PRATIQUES DE CHIMIE
(جامعة عين تموشنت بلحاج بوشعيب, 2025) SEDIRI, Khaldia
السلطات الإدارية المستقلة
(جامعة عين تموشنت بلحاج بوشعيب, 2026) لعلام, محمد مهدي