Diferite tipuri de fibre pot fi folosite pentru a genera o îmbunătățire a comportării mecanice a betonului armat dispers. Însă gradul în care aceasta se produce, depinde si de anumite caracteristici ale secțiunii elementului structural. În această lucrare sunt studiate efectele adăugării fibrelor în funcție de geometria secțiunii nearmate transversal, dar și de cantitatea de armătură longitudinală asupra rezistenței la moment încovoietor și forță tăietoare. Rezultatele arată o creștere semnificativă a momentelor capabile pentru un dozaj mare de fibre si armări longitudinale limitate, dar si o creștere semnificativă a forței tăietoare capabile pentru un dozaj mare, independent de cantitatea de armătură longitudinală.

Cuvinte Cheie: beton armat dispers, moment încovoietor, forță tăietoare, rezistență

Different types of fibers can be used to improve the mechanical behavior of steel fiber reinforced concrete. However, the degree to which this occurs also depends on certain characteristics of the structural element section. This paper studies the effects of adding fibers on the bending moment and shear force resistance depending on the geometry of the transversely unreinforced section, but also on the amount of longitudinal reinforcement. The results show a significant increase of the resisting moments for a high fiber content and reduced longitudinal reinforcement, but also a significant increase of the resisting shear force for a high fiber content, regardless of the amount of longitudinal reinforcement

Keywords: fiber reinfored concrete, bending moment, shear force, strength,

Road pavements in Nigeria and other developing regions are often faced with premature failures due to suboptimal asphalt mix designs, particularly related to bitumen content (5%, 6%, 7% and 8%) as this affects the mechanical and durability properties of asphalt used for flexible pavement construction. Laboratory tests, including penetration, ductility, viscosity, flash and fire points, Marshall Stability, flow, bulk density, air voids and drying shrinkage tests were conducted. The results indicate that an optimum bitumen content of approximately 6.67% provides the best balance of stability, density and durability. Higher contents lead to excessive deformation and rutting, while lower contents result in inadequate cohesion and strength. These findings highlight the importance of adequate mix design to enhance pavement performance and longevity in similar conditions

Keywords: bitumen content, asphalt, flexible pavement, Marshall Stability, optimum

The article aims to present in general terms a concept that can be applied to streamline the cooling and hot water preparation processes in buildings located near surface water sources. The proposed solutions use logical principles, available equipment and are economically accessible from the point of view of cost-benefit analysis.

Keywords: energy efficiency, free cooling, hot water, water-water heat pump

Recent advancements in material research and technological innovations in the processing of raw materials for concrete production, combined with global shifts and the pursuit of sustainability, have prompted increased interest in the development of novel concrete mixtures. Despite several decades of intensive research in concrete technology, the practical implementation of these advancements remains relatively limited. This paper reviews existing testing methods and synthesizes the most relevant findings, while emphasizing the specific contributions and limitations of each study.

Keywords: engineered cementitious composites, mechanical properties, sustainability

This article presents a preliminary evaluation of a low-cost solar drying system, built entirely from recycled materials and tested for marine biomass applications. The experiment was set up using an air solar collector constructed from a reused window frame and a drying chamber housed inside a repurposed refrigerator. Tests were conducted on commercial wakame (Undaria pinnatifida) under forced convection, using a solar simulator with 2.0 kW halogen lamps. After 3.75 hours of system operation, a 47.2% reduction in mass was observed, from 477.7 g to 252.3 g. The recycled collector raised the drying air temperature by about 14...15°C above ambient, with a peak of 33.9°C and an air velocity of 0.5...0.6 m/s. The results show that the system is promising, but insulation and airflow need improvement to increase even further the drying air temperature

Keywords: solar drying, TSC, recycled materials, algae, energy efficiency

Variable refrigerant flow systems offer significant advantages over traditional air conditioning systems. They enable individual temperature control for each indoor unit, providing superior comfort compared to the uniform settings of conventional systems. VRF optimizes energy efficiency by adjusting the refrigerant flow according to overall demand, thus preventing excessive energy consumption. Due to their scalability and easier integration into modern buildings, VRF systems represent a highly efficient and adaptable solution for contemporary climate control.

Keywords: Variable, efficiency, systems, refrigerant

The European Commission's (EC) policy to phase out fossil fuels from the energy system has forced the reconfiguration of electricity systems (ESS) as a result of the large-scale introduction of renewable energy systems (RES). Achieving these objectives while ensuring energy security must lead to a balanced energy mix capable of ensuring an energy price that can be borne by end consumers, a goal that can be achieved by installing energy storage systems

Keywords: storage, energy, wind, photovoltaic, RES, energy securyty, cost

Tendința actuală de a reduce emisiile de gaz cu efect de seră prin creșterea eficienței consumului de combustibil fosil implică utilizarea materialelor mai ușoare în construcția clădirilor, cu amprenta de carbon mai redusă, comparabil cu materialele aplicate în prezent în mod obișnuit. Compozitele preparate din fibre vegetale constituie o soluție viabilă pentru atingerea acestui obiectiv. Precursorii adoptați pentru producerea compozitului geopolimeric au fost cenușa zburătoare, zgura de furnal granulată și cenușa cojilor de orez, ca materiale aluminosilicatice cu proprietăți de cementare, la care au fost adăugate fibre de cânepă cu rolul major de armare a compozitului. Rezultatele au arătat creșterea rezistenței la compresiune și încovoiere.

Cuvinte Cheie: fibră vegetală, compozit geopolimeric, armătură, rezistență, fibră de cânepă.

The current trend to decrease greenhouse gas emissions through increasing the efficiency of fossil fuel consumption implies the use of lighter materials in building construction, with a lower carbon footprint compared to materials commonly applied in the present. Composites prepared from vegetable fibres constitute a viable solution to reach this objective. The precursors adopted for the production of the geopolymer composite were fly ash, granulated blast furnace slag, and rice husk ash, as aluminasilicate materials with cementitious properties, to which hemp fibres were added with a major role in reinforcing the composite. Results showed increasing the compression and flexure strength.

Keywords: vegetable fibre, geopolymer composite, reinforcement, strength, hemp fibre

The main source of energy loss within water supply systems is found within the loss of water from within said systems.Understanding the reasons for these losses and taking the proper steps in curtailing their occurence while also reinforcing the reliability of the systems will ensure not only the optimal operational regime for the system but also increase the energy economy.

Keywords: water losses, water supply systems, energy consumption

Lucrarea prezintă o analiză comparativă între producția estimată și cea reală a unui sistem fotovoltaic rezidențial instalat pe o locuință unifamilială. Scopul este evaluarea acurateței simulărilor realizate cu ajutorul software-urilor PV*Syst și PVGIS, utilizând diverse baze de date climatice. Sistemul analizat are o putere instalată de 6.56 kWp și este echipat cu panouri monocristaline și un invertor on-grid. Prin compararea rezultatelor simulate cu datele reale înregistrate lunar, se evidențiază diferențele dintre performanța estimată și cea observată în exploatare. Rezultatele subliniază importanța validării simulărilor prin măsurători practice și relevanța alegerii corecte a datelor meteorologice pentru dimensionarea corectă a unui sistem fotovoltaic și estimarea rentabilității investiției.

Cuvinte Cheie: sistem fotovoltaic rezidențial, simulare, energie regenerabilă

This paper provides a comparative analysis of the estimated versus actual energy production of a residential photovoltaic system installed on a single-family home. The aim is to assess the accuracy of simulations conducted using PV*Syst and PVGIS software, using different climatic data sources. The system under study has a total installed capacity of 6.56 kWp and it is equipped with monocrystalline panels and an ongrid inverter. By comparing the simulated results with real data recorded monthly, the differences between the estimated and observed performance during operation are highlighted. The findings emphasize the importance of validating simulations through practical measurements and the relevance of selecting appropriate meteorological data for accurately sizing a photovoltaic system and estimating the return on investment.

Keywords: residential photovoltaic system, simulation, renewable energy

Lucrarea analizează impactul Programului EcoVoucher asupra dezvoltării durabile a sectorului energetic din Republica Moldova. Lansat în noiembrie 2023 cu sprijinul PNUD (Programul Națiunilor Unite pentru Dezvoltare) Moldova si finanțat de Uniunea Europenea, prin intermediul fostei Agenții pentru Eficiență Energetică, actualul Centru Național de Energie Durabilă (CNED), programul a avut drept scop sprijinirea gospodăriilor vulnerabile în procesul de înlocuire a echipamentelor electrocasnice vechi cu unele moderne, eficiente energetic. În etapa pilot, desfășurată între octombrie 2023 și iulie 2024, au fost distribuite 198.685 de vouchere, dintre care 39.084 au fost valorificate, ceea ce a generat economii anuale de circa 1,6 milioane kWh sau 7 milioane lei, contribuind la reducerea emisiilor cu peste 830 kg CO₂ anual. Ulterior, programul a fost preluat complet de către CNED , care în 2024 a emis 17.305 vouchere, dintre care 7.223 au fost utilizate, obținându-se economii suplimentare de 1,5 milioane kWh sau 6,6 milioane lei, contribuind la reducerea de emisii cu 789,6 kg CO₂ anual.

Cuvinte Cheie: Sectorul energetic, programe, EcoVoucher, dezvoltare durabilă, eficiență energetică.

The paper analyzes the impact of the EcoVoucher Program on the sustainable development of the energy sector in the Republic of Moldova. Launched in November 2023 with the support of UNDP (United Nations Development Programme) Moldova and funded by the European Union, through the former Energy Efficiency Agency-now the National Center for Sustainable Energy (CNED) -the program aimed to support vulnerable households in replacing old household appliances with modern, energy-efficient ones. During the pilot stage, carried out between October 2023 and July 2024, a total of 198,685 vouchers were distributed, of which 39,084 were redeemed, resulting in annual energy savings of approximately 1.6 million kWh or 7 million MDL, and contributing to a reduction of over 830 kg of CO₂ emissions annually. Subsequently, the program was fully taken over by CNED, which in 2024 issued 17,305 vouchers, of which 7,223 were used, achieving additional savings of 1.5 million kWh or 6.6 million MDL, and contributing to a reduction of 789.6 kg of CO₂ emissions annually.

Keywords: Energy sector, programs, EcoVoucher, sustainable development, energy efficiency.

Articolul prezintă realizarea și analiza unei simulări de evacuare pentru nivelul parter al unei clădiri destinate conferințelor și evenimentelor, folosind modelarea geometrică în SketchUp și simularea comportamentului ocupanților în Pathfinder. Au fost definite 31 de încăperi, 41 de uși (11 de evacuare), și o populație compusă din 524–526 ocupanți, incluși cu profiluri variabile privind viteză, comportament și dimensiuni antropometrice. Au fost analizate trei scenarii: evacuare normală, evacuare cu persoane cu dizabilități și blocarea unei uși, respectiv scenariu sever cu 7 uși blocate. Rezultatele indică creșteri ale timpului de evacuare până la 121,8 s și apariția zonelor de congestie cauzate de distribuția neuniformă și restrângerea căilor de evacuare. Studiul evidențiază importanța redundanței căilor de evacuare, configurării optime a mobilierului și asistenței pentru persoane vulnerabile.

Cuvinte Cheie: simulare evacuare, Pathfinder, SketchUp, securitate la incendiu comportament ocupanți, flux de persoane

The article presents the development and analysis of an evacuation simulation for the ground floor of a building intended for conferences and events, using geometric modeling in SketchUp and occupant behavior simulation in Pathfinder. A total of 31 rooms and 41 doors (11 used as evacuation exits) were defined, along with a population of 524–526 occupants, assigned with variable profiles regarding speed, behavior, and anthropometric dimensions. Three scenarios were analyzed: normal evacuation, evacuation including persons with disabilities and one blocked exit, and a severe scenario with seven exits unavailable. The results show increases in evacuation time up to 121.8 seconds and the occurrence of congestion zones caused by uneven occupant distribution and reduced evacuation paths. The study highlights the importance of redundancy in evacuation routes, optimal furniture arrangement, and assistance for vulnerable individuals.

Keywords: evacuation simulation, Pathfinder, SketchUp, fire safety, occupant behavior, people flow.

Articolul prezintă propuneri de eficientizare energetică a sistemelor complexe de încălzire/răcire și preparare apă caldă de consum prin conceptualizarea a două sisteme pentru testarea și gestionarea eficientă din punct de vedere energetic aplicate unui ansamblu mixt format din două pompe de căldură de tip apă-apă, respectiv aer-apă.

Cuvinte Cheie: încălzire/răcire, pompe de căldură, eficientizare energetică

The article presents proposals for energy efficiency of complex heating/cooling and domestic hot water systems by conceptualizing two systems for energy-efficient testing and management applied to a mixed ensemble consisting of two water-to-water and air-to-water heat pumps, respectively.

Keywords: heating/cooling, heat pumps, energy efficiency

The article presents quantitative and qualitative aspects of lighting, its influence on activities carried out in educational and health spaces, and the impact of artificial lighting through its effects, especially blue light, on health.

Keywords: artificial lighting, blue light, LED, health