Fire extinguishing properties of novel ferrocene/surfynol 465 dispersions

This paper reports a novel fire-extinguishing agent: an aqueous dispersion of fine ferrocene particles. In this study, the ferrocene–water–surfactant dispersions were prepared to optimize the gas-phase concentration of ferrocene, and their ability to extinguish heptane fires was examined. The fire-extinguishing efficiency was characterized by three parameters: the ferrocene concentration in the dispersion (0–175 ppm), the surfactant used, and the ferrocene particle size (d₅₀=10.4, 11.4, 21.5, and 68.8 μm). The results indicated that (1) the ferrocene (d₅₀=10.4 mm)–water–surfynol 465 dispersion is the most stable among the dispersions tested, (2) the ferrocene–water–surfynol 465 dispersions have an optimal value of ferrocene concentration regarding the extinguishing time, and (3) in the ferrocene particle size range of 10.4–21.5 μm, the minimum extinguishing time of the ferrocene–water–surfynol 465 dispersions is remarkably shorter (1.2 s) than those observed when using a conventional wet chemical agent (45 wt% aqueous solution of potassium carbonate, 12.9 s).     

The effect of thiosemicarbazide on corrosion resistance of steel reinforcement in concrete

This study describes a laboratory investigation of the influence of thiosemicarbazide (TSC) on the corrosion of reinforcing steel and the compressive strength of concrete. The effect of TSC on the corrosion resistance of steel reinforced concrete was evaluated by carrying out electrochemical tests in NaCl and NaCl + TSC solutions for 60 days. Polarisation resistance (R_p) values of TSC added reinforced concrete were much higher than those without TSC. Similarly, AC impedance spectra revealed that the resistance of TSC mixed electrodes were also quite higher than those without. The compressive strength of concrete specimens containing TSC was measured and an increase of 20–25% was observed.     

A study on improvement of durability of reinforced concrete structures mixed with Natural Inorganic Minerals

As a fundamental study on the corrosion resistance of reinforced concrete structures using Natural Inorganic Minerals exposed to carbonation environment. The test specimens were concrete(W/C = 60%) with Natural Inorganic Minerals content of 0% and 10%. Accelerated arbonation and autoclave corrosion accelerated curing were then conducted with them. The corrosion resistance of steel in concrete with Natural Inorganic Minerals content of 0% and 10% was examined by corrosion form, half-cell potential, polarization resistance, corrosion area and weight loss after 24 h of autoclave corrosion accelerated curing.The results of the study showed that as for steel in concrete with Natural Inorganic Minerals content of 10%, the corrosion resistance was more excellent than steel in concrete with Natural Inorganic Minerals content of 0%.     

Long-term bond performance of GFRP bars in concrete under temperature ranging from 20 °C to 80 °C

Eighty pull-out specimens were used to study the effect of temperature ranging from 20 °C to 80 °C in dry environment on bond properties between Glass Fiber Reinforced Polymer (GFRP) bars and concrete. The pullout-test specimens were subjected during 4 and 8 months to high temperatures up to 80 °C and then compared to untreated specimens (20 °C). Experimental results showed no significant reduction on bond strength for temperatures up to 60 °C. However, a maximum of 14% reduction of the bond strength was observed for 80 °C temperature after 8 months of thermal loading. For treated specimens, the coefficient β in the CMR model, which predicts the bond–stress–displacement behavior, seems to be dependant with the temperature.     

Bonding strength of wood materials bonded with different adhesive after aging test

In this study, it is aimed to describe the effects of adhesives (PVAc, Desmodur-VTKA and phenol formaldehyde) on Uludag fir (Abies Bornmüllerina M.) and Oriental beech (Fagus Orientalis Lipsky) cut tangentially and exposed to heating tests (40, 60, and 80 °C) and heating duration (30, 60 and 90 days) and controls. Consequently, when compared to control samples, the highest decrease of 26.2% in average with Oriental beech and 18.5% in average with Uludag fir was obtained with the samples bonded with D-VTKA adhesive kept for 90 days. At high temperatures phenol formaldehyde adhesives can be advised as the building material used for long terms.     

Kinetic characterization of saponified domestic lipid residues aerobic biodegradation

As the sanitary landfill dumping of the lipidic residues are now prohibited by French legislation, new treatment ways such as biodegradation or incineration have to be developed. This work carried out on domestic grease demonstrates the effect of their saponification on their aerobic biodegradation. The composition of the lipidic residues mixture used in this work and collected from a wastewater plant was characterized (70% dry matter, 90% HEM, 80% of free and esterified fatty acids, 20% of other lipidic materials, DCO/lipids=2.4). Both the solubilization of grease (apparent CMC=0.7 g HEM/l) and their micellization by saponification highly enhanced the rate of grease degradation by an activated sludge. This pointed out that the elimination reaction was controlled by the grease transfer from lipidic phase to cell. During batch culture (X₀=1.8 g MLSS/l, S₀=3.5 g HEM/l), the degradation rate was more than 0.2 g HEM/l/h and the removal yield was 60% for HEM, namely 70% for fatty acids and 40% for unsaponifiable compounds. This low removal yield could be linked to the high foaming onset which did not allow the biological degradation reaction to continue.     

Turbidity changes caused by collapse of cyanobacterial gas vesicles in water pumped from lake Kinneret into the Israeli national water carrier

The cyanobacterium Aphanizomenon ovalisporum Forti appeared in Lake Kinneret for the first time in the summer and autumn of 1994 and reappeared in 1995–1997. In 1994 it formed a large bloom (6000 filaments ml⁻¹) that caused high turbidity (up to 7 NTU), which is attributed mainly to light scattering by gas vesicles. When lake water was pumped into the high-pressure pipe (2.5 MPa) of the Israeli National Water Carrier (INWC) the turbidity of the water decreased by 65%, the Aphanizomenon filaments lost their buoyancy and some filaments fragmented. Application of 0.6 MPa pressure to cultures of the Lake Kinneret strain of A. ovalisporum in a pressure nephelometer caused collapse of all gas vesicles; the turbidity decreased by 80% and all of the filaments sedimented. The mean critical collapse pressure of the gas vesicles (p_c) was 0.58±0.02 MPa (with cells suspended in hypertonic sucrose solution), the apparent mean critical collapse pressure (p_a) was 0.27±0.02 MPa (with cells suspended in culture medium) and the mean turgor pressure (p_t) was 0.33±0.02 MPa. The value of p_a is lower than the pressures in any of the five high-pressure pipes (0.6–2.5 MPa) along the INWC. It is concluded that gas vesicle collapse caused the observed decrease in turbidity in the system. The combined physical, chemical and biological treatments given in the INWC system resulted in a 99.9% decrease in the A. ovalisporum biomass.     

Effects of impregnation with Imersol-aqua on the modulus of elasticity in bending of laminated wood materials

The aim of this study was to investigate the impacts of impregnation with Imersol-aqua on the modulus of elasticity in bending (MOE) of some laminated wood materials. For this aim, oriental beech (Fagus orientalis Lipsky), oak (Quercus petrea Liebl.), Scotch pine (Pinus sylvestris Lipsky), oriental spruce (Picea orientalis Lipsky) and Uludağ fir (Abies bornmülleriana Lipsky) wood materials impregnated with Imersol-aqua according to ASTM D 1413-99 and producers’ definition. Laminated wood samples were produced from impregnated wood materials according to TS EN 386 in the five ply form (4 mm each) from oriental beech, oak, Scotch pine, Uludağ fir and oriental spruce wood by using Desmodur-VTKA adhesive. The MOE values were measured according to TS EN 408. Consequently, the MOE of impregnated + laminated (I + L_W) softwoods, pine, spruce and fir increased, respectively by 8.07%, 2.62% and 2.45% whereas the MOE of laminated + laminated hardwoods, beech and oak decreased, respectively by 5.06% and 4.37% with respect to laminated control samples (L_W). Considering the interaction of wood type and process, the MOE was obtained from laminated oriental beech, whereas the lowest was found for impregnated Uludağ fir. In consequence, in the massive construction and furniture elements that the MOE after the impregnation and lamination (I + L_W) is of great concern, oriental beech and Scotch pine materials could be recommended.     

Mechanistic-empirical mixture design for hot mix asphalt pavement recycling

Mixture design of six asphalt mixtures containing Reclaimed Asphalt Pavement (RAP) were evaluated by using a mechanistic-empirical approach. The testing methodology involved determination of the key mechanical properties and durability of wearing course and base course materials containing RAP at three different levels of addition (i.e. 10%, 30% and 50%), manufactured to a supplied specification, and the rheological properties of binder used in, and recovered from, these materials. In order to optimise both rutting and fatigue resistance, the recycled mixtures were manufactured by using 80/100 pen virgin bitumen (which is one grade softer than the 60/70 pen bitumen conventionally used for the respective parent asphalt materials), with or without added rejuvenating oil. This paper demonstrates that the asphalt mixtures containing RAP performed at least similar to, or better than, that of conventional asphalt materials.     

Influence of fine tailings on polyester mortar properties

The purpose of this study is to examine the basic properties of polyester mortars using a fine tailings (FT) from an abandoned mine as a filler. FT with sizes of 10–69 μm is obtained through the centrifugal separation of tailing (TA), and tested for such basic properties, as particle shape, fineness of size distribution, liquid resin absorption, and heavy metal leaching. Polyester mortars with FT and ground calcium carbonate (GC) are prepared with various filler-(filler + binder) ratios and replacements of GC with FT, and tested for working life, flexural and compressive strengths, and chemical corrosion resistance. As a result, FT has almost the same properties as GC in terms of particle shape, fineness of size and liquid resin absorption. The working life of polyester mortars is prolonged with an increased filler-(filler + binder) ratio and replacement of GC with FT. From the vantagepoint of the strength development of the polyester mortars with FT, it is recommended that the filler-(filler + binder) ratio and replacement of GC with FT should be controlled at 50% or less. Mass and strength changes are generally lower in mortars containing FT than in those containing GC in all chemical solutions.     

Investigation of effects of aggregate size on the fracture behavior of high performance concrete by acoustic emission

As an important component of concrete, aggregate has a significantly influence the fracture behavior of high performance concrete. In this paper, the effects of aggregate size distribution on the fracture properties of high performance concretes with strength ranging from 50 MPa to 80 MPa were investigated under three-point-bending tests. Acoustic emission (AE) technique with three-dimensional orientation feature was applied to study the effect of maximum aggregate size (d_max) on fracture properties and the facture process zone (FPZ) at the crack tip. The results showed that the fracture energy of concrete increased with the increase of d_max. The larger the size of the aggregate, the more significant the deflection of propagating crack and the greater the FPZ can form. That AE hits had a very good relation indicating its potential to measure inner damage of concrete during cracking.     

Enhanced ignition of biomass in presence of NOx

Accumulation of combustible biomass residues on hot surfaces of processing machineries can pose fire hazards. In addition, the presence of nitrogen oxides (NO_x) from plant equipment alters the local conditions, aggravating the propensity for low temperature ignition risks. This study presents an experimental study on a relative effect of NO_x on ignition temperature of morpholine, an important surrogate of biomass, to reveal the sensitising role of NO_x in ignition of biomass fuels and to gain mechanistic insights into the chemical aspect of this behaviour in fire. The experiments employed a flow-through tubular reactor, operated at constant pressure and residence time of 1.01 bar and 1.0 s, respectively, and coupled with a Fourier-transform infrared spectroscope. For a representative fuel-rich condition (Φ=1.25), the concentration of NO_x as small as 0.06% lowers the ignition temperature of morpholine by 150 °C, i.e., from approximately 500 °C to 350 °C. The density functional theory (DFT) calculations performed with the CBS-QB3 composite method, that comprises a complete basis set, characterised the dynamics and energies of the elementary nitration reactions. We related the observed reduction in ignition temperature to the formation of unstable nitrite and nitrate adducts, as the result of addition of NO_x species to morphyl and peroxyl radicals. Furthermore, the reaction of NO_x with low-temperature hydroperoxyl radical leads to the formation of active OH species that also propagate the ignition process. The present findings quantify the ignition behaviour of biomass under NO_x–doped atmospheres. The result is of great importance in practical applications, indicating that safe operation of wood-working plants requires avoiding trace concentration of NO_x within the vicinity of biomass residues. This can be facilitated by proper (and separate) venting of engine exhausts.     

Influence of corrosion crack patterns on the rate of crack widening of RC beams

Corrosion crack widths are often used by structural engineers in the field to predict level of steel corrosion as well as residual load-bearing capacities of corroding RC structures. This paper presents further work on this matter but with focus on corrosion crack patterns and how they affect rate of crack widening. It is based on results from a research where 17 quasi-full-scale (153 × 254 × 3000 mm) RC beams were corroded under various levels of sustained loads. The rate of widening of corrosion crack widths was found to be very much dependent on crack patterns. Deformation of cover concrete under each crack pattern was discussed. It was found that at maximum crack widths below 0.6 mm, the majority of beams exhibited nearly similar crack patterns as well as rate of widening of corrosion cracks. A mass loss of steel of 1% corresponded to a maximum crack width between 0.14 and 0.22 mm. At large crack widths (>0.6 mm), various beams exhibited very different rates of crack widening. It was shown that at crack widths above 0.6 mm, to be conservative an increase in mass loss of steel of 1% corresponded to corrosion crack widening of 0.02 mm.     

Strength correlation between individual block,prism and basic wall panel for load bearing interlocking mortarless hollow block masonry

This paper focuses on the development of the compressive strength correlation between the individual block, prism and basic wall panel for load bearing interlocking hollow mortarless blocks. The interlocking blocks used were developed by the Housing Research Centre at Universiti Putra Malaysia. The blocks consisted of stretcher, corner and half blocks. Forty individual block units from each type were tested under compression. The compressive strengths of 10 prisms assembled by stacking two stretcher blocks and two half blocks were evaluated. In addition, four wall panels each having a dimension of 1.2 × 1.2 m were assembled and tested under axial compressive loads. The results obtained were compared with those found in bonded masonry. BS 5628 Part 1:1992 were used for predicting of the compressive capacity of the bonded masonry. The interlocking mechanism, crack patterns and failure mechanism of the interlocking masonry specimens are highlighted and discussed.The correlations between the compressive strength of the interlocking masonry individual block (f_cb), prism (f_cp) and standard panel (f_cw) found in this analysis were f_cp = 0.47f_cb, f_cw = 0.83f_cp and f_cw = 0.39f_cb. Test results indicate that the interlocking mechanism and strength of the block in the load-bearing wall was satisfactory.     

Development of electrochromic evacuated advanced glazing

Electrochromic evacuated advanced glazing has been developed, combining optimum dynamic control of the solar radiation penetrating into buildings with a high degree of thermal insulation. This was achieved by the optimisation of the electrochromic device materials (electrochromic, ion storage, protective layers, transparent conductors and polymer electrolytes) and by the refinement of a sealing method for evacuated glazing. Electrochromic evacuated glazing prototypes with dimensions up to 40 cm × 40 cm have been fabricated using vacuum techniques and chemical methods. The prototypes exhibit excellent optical and thermal performance, with a contrast ratio up to 1:32 (visible dynamic transmittance range T_lum,bleached = 63% and T_lum,colored = 2%), coloration efficiency up to 92 cm²/C and mid-pane U-values as low as 0.86 W m⁻² K⁻¹. Their durability in relation to real working environmental conditions has been assessed through indoor and outdoor testing. Such a glazing can be used in building applications to improve occupant thermal comfort, contribute to a reduction in space heating and cooling loads and allow for increased areas of fenestration thereby reducing artificial lighting loads. These factors reduce the energy demand for the building and therefore contribute to the reduction of carbon dioxide emissions.     

Inhibition of counterflow methane/air diffusion flame by water mist with varying mist diameter

In the present study, the effect of fine water mist on extinguishment of a methane–air counterflow diffusion flame was investigated to understand the underlying physics of fire extinguishment of highly stretched diffusion flame by water mist. Twin-fluid atomizers were used to generate polydisperse water mist of which Sauter mean diameters were 10, 20, 40, and 60 μm. When water mist is not added, the critical stretch rate at extinguishment is 439 s⁻¹ as compared to the theoretical value of 460 s⁻¹. For the case with water mist addition, when the stretch rate is small enough, almost all the water mist evaporates within the flame zone. On the other hand, for high stretch rate case, large mist droplets pass through the flame zone and can reach the stagnation plane. However, no oscillatory motion was found around the stagnation plane. Critical stretch rate at extinguishment decreases monotonously with the mass fraction of water mist independently of the mist diameter within the range of D₃₂ from 10 μm to 60 μm. On the other hand, with increase in the surface area parameter, the critical stretch rate at extinguishment decreases rapidly and becomes less sensitive at large surface area parameter, of which tendency is qualitatively in good agreement with theoretical predictions. For a constant surface area parameter, the critical stretch rate decreases with mist diameter because the mass fraction of water mist should increase in proportion to the mist diameter to keep the surface area parameter constant. When the water mist evaporates completely in the flame zone as in the present study, the mass fraction of the water mist is the dominant factor for fire extinguishment, rather than the surface area parameter. Therefore, an appropriate combination of stretch rate and water mist mass fraction should be provided to suppress effectively a given fire with a small amount of water mist.     

Impacts of impregnation chemicals on combustion properties of the laminated wood materials produced combination of beech and poplar veneers

The aim of this study was to investigate the effects of impregnation with boron compounds Borax (B_X), Boric acid (B_A), B_X + B_A, Imersol-Aqua (I_AQUA) and Timbercare-Aqua (T_AQUA) on combustion properties of the laminated wood materials produced combination of Oriental beech and poplar veneers bonded with Desmodur-VTKA (D_V) and Poly(vinyl acetate) (P_VAc) adhesives. The test samples, prepared from beech (Fagus orientalis Lipsky) and poplar (Populus nigra Lipsky) woods, were impregnated boron compounds by vacuum, I_AQUA by dipping and T_AQUA by brushing methods according to ASTM D 1413-76-99 and directions of the manufacturer. The laminated wood materials were prepared in the form of five layers, 4 mm thickness from the impregnated beech and poplar veneers according to TS EN 386. Combustion properties of samples after laminated and impregnated process were determined according to ASTM E 160-50. Considering the interaction of combustion type and impregnation materials, combustion temperature was found the highest in flame source combustion (F_SC) + T_AQUA (528.150 °C) but the lowest in without flame source combustion (WF_SC) + B_A (391.333 °C). Consequently, boron compounds and I_AQUA showed a decreasing impact on combustion properties of the laminated wood materials, produced combination of beech and poplar veneers, bonded with D_V. In consequence, impregnation with boron compounds and Imersol-Aqua of the laminated wood materials, bonded with Desmodur-VTKA, provides security for the usage of having high risk of fire.     

Comparison between lighting performance of a virtual natural lighting solutions prototype and a real window based on computer simulation

This article discusses the measurement and simulation of a first generation prototype of Virtual Natural Lighting Solutions (VNLS), which are systems that can artificially provide natural lighting as well as a realistic outside view, with properties comparable to those of real windows and skylights. Examples of employing Radiance as a simulation tool to predict the lighting performance of such solutions are shown, for a particular case study of a VNLS prototype displaying variations of a simplified view of overcast, clear, and partly cloudy skies. Measurement and simulation were conducted to evaluate the illuminance distribution on workplane level. The key point of this study is to show that simulations can be used to compare an actual VNLS prototype with a hypothetical real window under the same sky scenes, which was physically not possible, since the test room was not located at the building׳s façade. It is found that the investigated prototype yields a less rapidly drop illuminance distribution and a larger average illuminance than the corresponding real window, under the overcast (52 lx compared to 28 lx) and partly cloudy (102 lx compared to 80 lx) sky scenes. Under the clear sky scene, the real window yields a larger average illuminance (97 lx) compared to the prototype (71 lx), due to the influence of direct sunlight.     

Influence of traffic force on pollutant dispersion of CO,NO and particle matter (PM2.5) measured in an urban tunnel in Changsha,China

Environmental safety issues and ventilation problems caused by the construction of urban tunnel have increasingly been attracting people’s attention. Previous studies in China have mainly focused on vehicle emissions and ventilation control technologies in road tunnels, resulting in a research gap on urban tunnel ventilation engineering design. Therefore, a detailed monitoring investigation was conducted from May 22 to June 2, 2013 in Changsha Yingpan Road Tunnel, China. The study aim was to measure the traffic characteristics, air velocity and the carbon monoxide (CO), nitrogen oxides (NO_x) and fine particulate matter (PM_2.5) concentrations in this tunnel, which has two lanes per bore and multiple ramps. Measurement results show that during the workday morning peak, the maximum traffic flow was 1560 passenger-car-unit/h per lane with vehicle speed around 33.6 km/h in the eastbound tunnel, the average air velocity was 3.07 m/s, and the proportion of the light-duty vehicles (LDV) was 97.3%. Under the traffic force (not open fan), the CO and NO average concentrations at the main tunnel outlet were 20.3 ppm and 1.65 ppm, respectively. The gas pollutant concentrations are effectively controlled within the multiple-ramps tunnel and the design air volume flow is noticeably reduced. The traffic air flow was found to provide 32.5% of the required air volume to dilute NO_x in blocked traffic condition (vehicle speed of 10 km/h). In addition, the PM_2.5 concentration is mainly affected by the value of background outside the tunnel. The result can provide a quantitative assessment method to support pollutant concentration control and contribution of requested air volume by traffic flow in urban complex structure tunnel.     

Testing of full-scale concrete bridge deck slabs reinforced with fiber-reinforced polymer (FRP) bars

This paper presents an experimental study investigating the behavior of FRP-reinforced concrete bridge deck slabs under concentrated loads. A total of eight full-scale deck slabs measuring 3000-mm long by 2500-mm wide were constructed. The test parameters were: (i) slab thickness (200, 175 and 150 mm); (ii) concrete compressive strength (35–65 MPa); (iii) bottom transverse reinforcement ratio (1.2–0.35%); and (iv) type of reinforcement (GFRP, CFRP, and steel). The slabs were supported on two parallel steel girders and were tested up to failure under monotonic single concentrated load acting on the center of each slab over a contact area of 600 × 250 mm to simulate the footprint of sustained truck wheel load (87.5 kN CL-625 truck). All deck slabs failed in punching shear. The punching capacity of the tested deck slabs ranged from 1.74 to 3.52 times the factored load (P_f) specified by the Canadian Highway Bridge Design Code (CHBDC) CAN/CSA S6-06. Besides, the ACI 440.1R-06 punching strength equation greatly underestimated the capacity of the tested slabs with an average experimental-to-predicted punching capacity ratio (V_exp/V_pred) of 3.17.