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  Numarul 2/2019

Volumul 10 (2019), Nr. 2

Stabilization of Expansive Soil With Coal slurry and Fly Ash
Dadi Hamza, Berga Abdelmadjid, Khelifi Abdelghafour

Due to its great risk on buildings, improving the characteristics of expansive soil is a large concern in the field of civil engineering. On an other hand, valuing of industrial waste has become an urgent need to reduce the damage on both of the public health and the environment. The aim of this study is to evaluate the utility of Coal slurry and fly ash located in Bechar, Algeria on expansive soil stabilization. There is many researches use fly ash as stabilizer, in contrast of coal slurry. In the present work, the mixture of bentonite and sand is stabilized by the coal slurry and fly ash. An experimental program is realized to examine the effects of coal slurry and fly ash on particle-size analysis, the free swell, swell pressure, plastic index and surface area. The soil samples are prepared with three proportions of coal sterile and fly ash (4%, 8% and 12%). The results acquired are very encouraging and they show that the effect of coal slurry and fly ash on the geo-technical properties of expansive soils is very important.

Keywords: Expansive soil, Stabilization, coal slurry, fly ash, Swell pressure.

Aspecte privind optimizarea constructiv-funcționala a unui sistem de pompa de căldura cu compresie (cu sursa de rezerva) pentru īncălzirea unei clădiri rezidențiale sau prepararea apei calde de consum
Aspects regarding the constructive optimization of a compressed heat pump system (with a backup source) for heating a residential building or the preparation of hot water
prof. Florin Iordache,Ing. Mugurel Talpiga

In this paper is presented the physical model and mathematical approach which describe the equation system used in system calibration and design optimization. The system proposed for study is built from heat pump, for energy demand delivery, together with auxiliary heating source to face in all low temperature days, when heat pump work at maximum load but the required demand by the building is higher. The paper present few of the common used systems in market for which the mathematical equation system will be proposed to come in help designers for in simulation and cost optimization. Simulation of proposed design is realized and results are delivered. The system construction, is optimized by comparison study of design and simulation data for each system type proposed. The comparison study is used for cost estimation of system and energy balance.

Keywords: heat pump system

Simularea incendiilor prin utilizarea a trei metode diferite de introducere a fluxului de căldură (HRR-Heat Release Rate)
Fire simulation by using three methods of introducing HRR (Heat Release Rate)
Marius Dorin Lulea, Vlad Iordache, Ilinca Năstase

Prezentul articol īși propune să analizeze modelarea incendiilor prin trei posibile metode de introducere a fluxului de căldură(HRR- Heat Release Rate): constant sau cu creștere și descreștere liniară sau exponențială. Īn toate cazurile cantitatea totalăde energie introdusă este aceeași. Analiza comparativă a celor trei ne-a oferit informații cu privire la efectul metodei utilizate pentru modelarea incendiilor. Urmărind cum evoluează temperatura īntr-un punct s-a concluzionat că rezultatele sunt sensibil diferite. Cele trei tipuri de sursă duc la temperaturi maxime diferite, duc la temperaturi medii diferite dar și timpi diferiți de apariție a unor temperaturi la care corpul uman este afectat.

Cuvinte cheie: flux de căldură, modelarea incendiilor, sursă de incendiu, sursă de foc

This article aims to analyze the modeling of fires by three possible methods of introducing HRR (Heat Release Rate): constant or with linear or exponential growth and decrease . In all cases the total amount of energy introduced is the same. The comparative analysis of the three methods give us information about the effect of the method we used for modeling fires. Watching how the temperature evolve to one point we concluded that the results are quite different. The three types of source lead to different maximum temperatures, lead to different average temperatures but also different times of appereance of temperatures to which the human body is irreparably affected.

Keywords: Heat Release Rate, fire modeling, CFD

Aspecte privind predicția coroziunii electrozilor de pămāntare īn solul municipiului Timișoara Partea I. Măsurători
Aspects regarding the prediction of earth electrode corrosion in the soil of Timişoara municipality. Part I. Measurements
Ștefan PAVEL, Ioan-Bogdan PASCU, Bogdan-Ovidiu ȚĂRANU, Oana-Alexandra GRAD, Romeo NEGREA

Predicția coroziunii electrozilor de pămāntare instalați īn solul din orașul Timișoara

Cuvinte cheie: sol, electrod de īmpămāntare, coroziune, predicție

Corrosion prediction of galvanized steel ground electrodes in the soil of Timisoara

Keywords: soil, earth electrode, corrosion, prediction

Optimizarea salvării persoanelor īn caz de incendiu, din construcții, prin modelarea competențelor specifice
Optimizing rescue of people in the event of fire in construction by shaping specific skills
Conf.univ.dr.ing. Aurel Trofin

Organizarea apărării īmpotriva incendiilor īn contextul legislației actuale, presupune identificarea resurselor financiare la nivelul fiecărei instituții sau operator economic pentru achiziționarea de echipamente de protecție, formarea inițială a echipelor de primă intervenție și realizarea unor antrenamente specifice, necesare salvării angajaților īn cazul producerii unor incendii sau explozii. Pentru a avea succes īn astfel de situații, salvatorii de pe locul de muncă trebuie să dobāndească competențe specifice, iar antrenamentele periodice trebuie organizate īn condiții cāt mai apropiate de condițiile reale.

Cuvinte cheie: salvator, competențe, antrenament, intervenție, incendiu.

The organization of fire protection in the context of current legislation involves identifying the financial resources at each institution or economic operator for the purchase of protective equipment, initial training of first-intervention teams and specific instructions needed to save employees in the event of fires or explosions . In order to succeed in such situations, rescuers from work must acquire certain skills, and training sessions must be organized in conditions as close as possible to real conditions.

Keywords: rescuer, skills, training, intervention, fire.

Comportamentul termic neliniar, in regim nestationar, al peretilor din blocuri de material poros
Non-linear non-linear thermal behavior of porous block walls
prof. Florin Iordache

Lucrarea contine o analiza a comportarii in regim termic dinamic al peretilor alcatuiti din blocuri de tip BCA. Peretii despart o incinta in care are loc un incendiu care evolueaza dupa curba standard de temperatura de mediul de mediul exterior caracterizat de o temperatura de aproximativ 20o C. Peretele este alcatuit din 2 zone diferite din punct de vedere al proprietatilor si anume zona de camp (zona centrala a blocurilor de tip BCA) si zona de rost dintre blocurile de BCA, unde materialul este mortar adeziv pentru zidirea blocurilor. In lucrare se prezinta mai intai, la modul general, bazele teoretice care guverneaza procesul neliniar de transfer termic in regim nestationar in peretele din blocuri de tip BCA si se descrie pe scurt tehnica de simulare automata de urmarire a dezvoltarii procesului de transfer termic in masa peretelui. Rezultatele obtinute sunt prezentate defalcate atat tabelar cat si grafic pentru a putea avea o imagine sintetica asupra acestora.

Cuvinte cheie: pereti blocuri BCA, transfer termic

The paper contains an analysis of the dynamic thermal behavior of the walls made of BCA type blocks. The walls separate a room where a fire occurs that evolves after the standard ambient temperature curve of the outdoor environment characterized by a temperature of about 20o C. The wall is made up of two different areas in terms of properties, namely the field area (the central area of the blocks) and the area between the blocks, where the material is adhesive mortar for building blocks. The paper presents the theoretical bases that govern the non-linear thermal transfer non-stationary process in the wall of BCA blocks and briefly describes the automatic simulation technique for monitoring the development of the heat transfer process in the mass of the wall. The results obtained are presented tabularly and graphically so that you can have a synthetic image on them.

Keywords: BCA block walls, thermal transfer

The effect of nature the granulate on the evolution of the thermal conductivity of an resin concrete exposed to high temperatures

The knowledge of the thermal conductivity properties of concrete is essential in studying the behavior of concrete at high temperatures. This knowledge is so essential to feed the thermal behavior patterns and correctly simulate the temperature field developing in a concrete element in any type of heating. In this context, this work aims to follow the influence of the nature of the granulate on the evolution of the thermal conductivity of epoxy-based concretes. The experimental results obtained show that the mineralogical nature of the granulate great affects the conductivity of the concrete.

Keywords: resin concrete, the granulate, high temperature, thermal conductivity

Studiul calității aerului īn mediile urbane din Romānia
The study of air quality in urban areas from Romania
Mihai Dima, Vlad Iordache

Avānd īn vedere că īn ultimi ani poluarea aerului este considerată una dintre cele mai complexe și grave probleme cauzate de civilizație, aceasta avand un impact masiv asupra sănătății oamenilor, dorim să evidențiem gradul de poluare īn mediile urbane din Romānia. Această lucrare s-a concentrat pe monitorizarea concentrațiilor poluanților precum, NOx, O3, și PM10 pe durata lunii Septembrie 2018. Rezultatele aratăcă s-au īnregistrat foarte multe depășiri ale limitei anuale. Sunt prezentate de asemenea sub formă de grafice valorile minime și maxime ale concentrațiilor poluanților și care oraș este cel mai afectat dintre cele studiate.

Cuvinte cheie: Calitatea aerului, Zone urbane, Compuși gazoși,PM10

Given that in recent years air pollution is considered to be one of the most complex and serious problems caused by civilization, which has a massive impact on human health, we want to highlight the degree of pollution in urban environments in Romania. This conclusion focused on the monitoring of pollutant concentrations such as NOx, O3 and PM10 during September 2018. The results show that there have been many exceedances of the annual limit. It is also presented the diagram of the minimum and maximum values of the pollutant concentrations and which is the most affected city of the studied ones.

Keywords: Air quality, Urban areas, Gaseous compounds, PM10

Mărirea eficienței energetice la sistemele electroenergetice eoliene funcționānd la viteze ale vāntului variabile īn timp Partea a I-a
Increasing energy efficiency in wind power systems operating at variable wind speeds over time. Part I
Lucian CRIȘAN, Simona POPA-ALBU, Meda Alexandra LAZĂR, Daniel BREBENARIU, Cristian MURĂRESCU, Marius DUDU, Ioan BORZA, Marius BABESCU

Īn prezenta lucrare, se propune o metodă de mărire a eficienței energetice la un sistem electroenergetic eolian, SEE, format dintr-o turbină de vānt, TV și un generator sincron cu magneți permanenți, GSMP, la viteze ale vāntului variabile semnificativ īn timp. Valoarea maximă a puterii TV, PTV(ω), se obține la funcționarea la viteza unghiulară mecanică, VUM, optimă, ωOPTIM, a cărei valoare depinde direct proporțional de viteza vāntului. Energie electrică obținută, īn intervalul de timp t, de la un SEE depinde de cele 2 mărimi funcționale de bază: 1) valorile vitezei vāntului, V, īn intervalul de timp t și 2) valorile VUM, ω, respectiv variația sa īn timp. Problema fundamentală īn realizarea unei eficiențe energetice maxime, la momentul de timp t, este corelarea valorii VUM curente, ω, cu valoarea vitezei vāntului de la momentul de timp respectiv. Prin măsurarea a două mărimi de bază: viteza vāntului V și VUM curentă, ω, se analizează posibilitatea captării unei energii eoliene maxime la SEE din locația MinAna-zona Dobrogea. Pentru a realiza o funcționare īn punctul de putere maximă, MPP, trebuie ca VUM curentă să fie ωOPTIM.

Cuvinte cheie: Sistem eolian, viteze ale vāntului variabile īn timp, modele matematice ale TV şi GSMP, viteza unghiulară mecanică, viteza vāntului, energie electrică debitată, puterea TV, puterea GSMP, inerție mecanică, ecuația momentului cinetic, simulări īn Scientific WordPlace, eficiența energetică.

This paper proposes a method of increasing the energy efficiency of a wind power system, SEE, consisting of a wind turbine, TV and a synchronous synchronous generator with permanent magnets, GSMP, at variable wind speeds over time. The maximum power of TV, PTV (ω), is obtained when operating at the mechanical angular velocity, VUM, optimum, ωOPTIM, the value of which depends directly on the wind speed. Electricity obtained over time t from an EEA depends on the two basic functional sizes: 1) Wind velocity values, V, in the time interval Δt, and 2) VUM, ω, respectively its variation over time. The fundamental problem in achieving the maximum energy efficiency at time t is to correlate the current VUM value ω with the value of the wind speed at that time. By measuring two basic sizes: wind speed V and current VUM, ω, the possibility of capturing a maximum wind energy in the EEA from the MinAna-Dobrogea area is analyzed. To perform at the MPP maximum power point, the current VUM must be OPTIM

Keywords: wind system, variable speed wind speeds, mathematical models of TV and GSMP, mechanical angular speed, wind speed, power consumption, TV power, GSMP power, mechanical inertia, kinetic momentum equation, Scientific WordPlace simulations, energy.

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