Retarding Influence Research Articles

Estimation of the influence of wood-fire retardants on fire behavior of some types of wood construction materials

In this paper the effect of fire front on the surface of wood samples (pine, aspen and larch) was considered to estimate the effect of different wood-fire retardants. Infrared thermography was used as a diagnostic method. Modern methods of IR-diagnostics and the use of thermal imagers eliminate the need for a large number of thermocouples which perturb the investigated medium during measurements. At the same time, a much better resolution in space and time can be obtained using infrared diagnostics. The surface temperature distribution was obtained for the test wood samples after exposure to a fire front that was modeled using pine needles. The ignition probability was estimated for the chosen experimental parameters for each kind of wood. In the infrared region the sample surface characteristics were recorded using a thermal imager JADE J530SB with a 2.5 − 2.7 micron optical filter that allowed measuring a temperature within the range of 500 − 850 K. In order to record a temperature within the range of 293 − 550 K, the recording was conducted without a filter. The fire hazard characteristics of wood after fire retardant treatment showed a significant reduction in the surface temperature and the resistance to fire for the chosen parameters of the experiment compared to the same untreated samples.

Influence of Interaction Retardation and Radiation Reaction on the Fano Resonance Efficiency in the System of Nanoparticles

The system of metallic nanospheroids in the field of monochromatic light wave under conditions of manifestation of the Fano resonance is considered. The dimensions of the nanospheroids are much smaller than the wavelength of the incident radiation, but distances between them can be arbitrary. An analysis is made of the influence of the interparticle interaction and the reaction field on the inhomogeneity of the energy distribution of the collective oscillations of electrons in the system (the Fano resonance efficiency). It is shown that both the retardation and the reaction field contribute to an increase in the resonance efficiency.

Effect of novel intumescent flame retardant on mechanical and flame retardant properties of continuous glass fibre reinforced polypropylene composites

In this study, the influence of a novel intumescent flame retardant (IFR) on the mode I interlaminar fracture toughness and flame retardant properties of continuous glass fibre reinforced polypropylene (CGF/PP) composites is presented. The novel IFR system that consists of ammonium polyphosphate/poly (ethanediamine-1, 3, 5 triazine-o-4-amion-2, 2, 6, 6- tetramentylniperidine) (APP/PETAT) was introduced into the CGF/PP unidirectional prepregs (UD) composites by hot-melt impregnation process. Double cantilever beam (DCB) tests were performed to evaluate the mode I interlaminar fracture toughness (GIC) by using modified beam theory (MBT). It was found from the experimental results that compared to the neat CGF/PP composite, the mode I fracture toughness initiation toughness (GIC init.) and propagation toughness (GIC prop.) of CGF/PP/12.5 wt% IFR composites were increased by an average of 99.7% and 119.11% respectively. Meanwhile, samples with 12.5 wt% IFR could self-extinguish with an oxygen concentration of 32.4% and exhibit lower fire spread speed in UL-94 test. Furthermore, the peak of heat release rate (PHRR), total heat release (THR), fire performance index (FPI), and mass loss rate (MLR) tests indicated that IFR could dramatically enhance the flame retardancy of the composites.

Effect of the modifier on the thermophysical properties of fireproof ethylene-vinyl acetate copolymer composition materials

The object of research is the thermophysical processes of fireproof composite materials: ethylene-vinyl acetate copolymer, which contain fire retardant fillers and a modifier. In order to ensure the incombustibility performance, polymer compositions have a high degree of filling up to 60 % by weight. A copolymer of ethylene with vinyl acetate is used as a polymer matrix. Inorganic fillers-flame retardants are aluminum oxide trihydrate with an average particle diameter of 1.5 μm and 3.0 μm, magnesium oxide dihydrate with an average particle diameter of 3.0 μm and 3.7 μm and hydromagnesite with an average particle diameter of 1.4 μm. One of the most problematic places is the process of processing such compositions.Aminosilane is used as a modifier. Using the method of thermogravimetric analysis and TGA/DSC differential scanning calorimetry, the melting and decomposition temperatures, the crystallinity degree, the specific heat, and the mass loss are determined.The results show that the melting points decrease with increasing modifier content for all samples. A significant decrease in the melting point is observed when using fillers with a large average particle diameter. The temperature of the decomposition beginning increases for all polymer compositions in which the modifier is introduced. The crystallinity degree increases with increasing content of the polymer composition modifier. The specific heat capacity of all polymer compositions increases with an increase in the amount of modifier. This is due to the influence of fillers-flame retardants and modifier on the formation of the structure of polymer compositions.This makes it possible to reduce the melting point by 1.2–16.2 degrees, depending on the chemical composition and dispersion of the flame retardant fillers in the presence of a modifier. The crystallinity degree increases and the specific heat capacity increases with an increase in the modifier content. The decomposition beginning temperature of polymer compositions increases significantly from 20 to 45 degrees.The results will be useful in the development of fireproof formulations of polymer compositions for cable products, taking into account their thermal characteristics.

Influence of growth retardant and inorganic fertilizers on vegetative growth of Chrysanthemum (Dendranthema grandiflora Ramat)

An experimental field vegetative growth parameters observation was recorded on the influence of growth retardant (CCC) and Inorganic fertilizers (NPK) on vegetative growth of Chrysanthemum cv. Birbal Sahni. To investigate the optimum concentrations of Chlormequat chloride (CCC) with three levels C1, C2 and C3 i.e.1000 ppm, 5000 ppm and 10000 ppm and also three increasing levels of inorganic fertilizers (NPK) i.e. NPK1 (100 kg N2 + 60 kg P2O5 + 40 kg K2O/ha), NPK2 (150 kg N2 +120 kg P2O5 + 80 kg K2O/ha) and NPK3 (200 kg N2 + 180 kg P2O5 + 120 kg K2O/ha) appreciably improved the vegetative growth of chrysanthemum. Minimum plant height (cm) were recorded at concentration of cycocel C2 (5000 ppm) while, maximum plant height (cm) with amount of NPK3 (200 kg N2 + 180 kg P2O5 + 120 kg K2O/ha) spread (cm), maximum plant spread (cm), diameter of main stem (cm), number of leaves, number of branches/plant and flower weight/plant (g) were recorded with a beneficially concentration at 5000 ppm of CCC and N3(200 kg N2 + 180 kg P2O5 + 120 kg K2O/ha) amount of inorganic fertilizers. However, combined application C2+NPK3 of CCC and NPK significantly affected the above characters of chrysanthemum cv. Birbal Sahni.

Influence of phenylphosphonic amide on rheological, mechanical and flammable properties of carbon fiber/RTM6 composites

Abstract The aim of this work was to study the influence of a high efficient halogen-free phenylphosphonic amide flame retardant (FP1) to epoxy resin (brand name RTM6) on the rheological, mechanical and water absorption properties of the carbon fiber/RTM6 epoxy composite (CFR). With a 8 wt% loading FP1 in RMT6, the processing of CFR/FP1 was able to use the equal condition with that of CFR since the viscosity of RTM6 was maintained at a similar level in the minimum viscosity temperature region. The addition of FP1 showed negligible impacts on the interlayer share strength (ILSS) and in-plane share strength (IPSS) of CFR. The interfacial strength between RTM6 matrix and carbon fiber was decreased due to the impact of FP1 on cross-linking density and polarity of RTM6. The flame retardant efficiency of FP1 showed difference in presence of carbon fiber or not in RTM6. RTM6/FP1 (8 wt%) had a LOI value of 38%, achieved a V-0 rating at thickness of 3.2 mm in UL 94 test and showed 60% reduction in peak of heat release rate. RTM6/carbon fiber/FP1 (8 wt%) had a LOI of 43%, while it showed reduced performance in UL 94 and cone calorimeter tests.

Effect of Chemical Reaction and Heat Absorption on MHD Nanoliquid Flow Past a Stretching Sheet in the Presence of a Transverse Magnetic Field

In this paper, authors investigate homogeneous-heterogeneous chemical reaction and heat absorption effects on a two-dimensional steady hydromagnetic Newtonian nanoliquid flow along a continuously stretching sheet. The flow field is subjected to a uniform magnetic field acting in a direction perpendicular to the direction of nanoliquid flow. A mathematical model of the physical problem is presented involving nonlinear partial differential equations with appropriate boundary conditions. These equations are then transformed into nonlinear ordinary differential equations using a suitable similarity transformation. Finally, approximate solutions of the transformed equations are obtained using the spectral quasi-linearization method. Results of fluid velocity, fluid temperature, and species concentration are depicted graphically, while the values of skin friction and Nusselt number are presented in tabular form. Fluid flow models of this kind find applications in catalytic reactors involving chemical reactions, insulation systems, and in heat exchangers. The applied magnetic field has a retarding influence on the nanofluid velocity and species concentration, while it does not have any significant effect on the nanofluid temperature. The homogeneous and heterogeneous reactions tend to decrease the species concentration.

Experimental study on the influence of the flame retardants on the flammability of R1234yf

R1234yf has been considered as an alternative refrigerant with the low global warming potential (GWP), but it is flammable. Therefore, it is necessary to study the reduction or inhibition of flammability of R1234yf by different flame retardants. This paper mainly contributed to the influence of two kinds of flame retardants on the flammability of R1234yf. Firstly, the flammability limits of R1234yf and the mixtures of R1234yf/R227ea and R1234yf/R134a were tested out. Then the relationship between their flammability limits characteristics with the ratio of the flame retardants to R1234yf were evaluated by the fitted equations. The critical suppression ratios of R227ea/R1234yf and R134a/R1234yf were obtained. The results indicated that the inhibitory effect of R227ea on R1234yf was better than that of R134a by comparative analysis. Finally, the flame colors and flame propagation velocity characteristics of R1234yf before and after the addition flame retardants were researched and analyzed. The research achievement will be of universal guiding significance for the security application of R1234yf.

Optimal Cold-Start Control of a Gasoline Engine

This article analyzes the influence of the ignition retardation on the fuel consumption, the cumulative tailpipe hydrocarbon emissions, and the temperature inside the three-way catalytic converter in a gasoline direct injection engine operated under idling conditions. A dedicated cylinder-individual, model-based, multivariable controller was used in experiments in order to isolate the effect of the ignition retardation on the hydrocarbon emissions as much as possible. An optimal control problem for a gasoline engine at a cold-start is formulated, which is used to interpret the experimental data obtained. The corresponding goal is to minimize the fuel consumption during an initial idling phase of a fixed duration while guaranteeing that the three-way catalytic converter reaches a sufficiently high final temperature and at the same time making sure that the cumulative hydrocarbon emissions stay below a given limit. The experimental data indicates that the engine should be operated with maximum ignition retardation in order to reach any temperature inside the three-way catalytic converter as quickly as possible concurrently with minimum tailpipe emissions and with the minimum possible fuel consumption.

Optimal Cold-Start Control of a Gasoline Engine

This article analyzes the influence of the ignition retardation on the fuel consumption, the cumulative tailpipe hydrocarbon emissions, and the temperature inside the three-way catalytic converter in a gasoline direct injection engine operated under idling conditions. A dedicated cylinder-individual, model-based, multivariable controller was used in experiments in order to isolate the effect of the ignition retardation on the hydrocarbon emissions as much as possible. An optimal control problem for a gasoline engine at a cold-start is formulated, which is used to interpret the experimental data obtained. The corresponding goal is to minimize the fuel consumption during an initial idling phase of a fixed duration while guaranteeing that the three-way catalytic converter reaches a sufficiently high final temperature and at the same time making sure that the cumulative hydrocarbon emissions stay below a given limit. The experimental data indicates that the engine should be operated with maximum ignition retardation in order to reach any temperature inside the three-way catalytic converter as quickly as possible concurrently with minimum tailpipe emissions and with the minimum possible fuel consumption.

Hygrothermal behaviour of compact roofs in wood frame constructions through on-site measurements

In order to reduce the total thickness of flat roofs, compact roofs are often promoted. Having the insulation between the wooden joists, these roofs are more slender. Compact roofs are however subjected to hygrothermal risks due to internal condensation, limited drying potential or sensitivity to moisture ingress, which can affect their durability. A long-term on-site measurement on five compact roofs, exposed to real Belgian outdoor climatic conditions is performed, in order to check the robustness of the tested construction elements and the real influence of smart vapour retarders, hygroscopic insulation and the colour of the waterproofing membrane.

The Kinetics of Precipitate Dissolution in a Nickel-Base Superalloy

The effect of microstructure and soft impingement on the kinetics of static dissolution of γ′ precipitates during supersolvus solution treatment of the powder-metallurgy nickel-base superalloy LSHR were determined experimentally and interpreted in the context of a simple diffusion model. The starting material had either a fine duplex structure of γ grains and γ′ precipitates (each of which were ~2 μm in diameter) or a structure comprising ~2-μm-diameter γ′ precipitates lying within large (~15 μm) γ grains. Using a direct-resistance-heated Gleeble® machine, the temperature of each sample was first equilibrated at a fixed subsolvus temperature (at which the microstructure was also stabilized) and then quickly raised to and held for a predetermined time in the single-phase γ field. The dissolution of γ′ was found to be approximately five times as fast for the duplex structure in comparison to the kinetics for the intragranular precipitates. The results were interpreted using numerical simulations of dissolution based on the Whelan model modified to account for a distribution of precipitates (rather than a single, isolated spherical particle) and soft impingement of diffusion fields. Using independently-measured values for diffusivity, precipitate composition, and phase equilibria as input, simulation predictions showed good agreement with the observations in terms of the temporal variation of volume fraction and average particle radius. By this means, insight into the retarding influence of soft impingement and the accelerating effect of pipe diffusion (due to stored dislocations) on the rate of dissolution was obtained

Changes in the elemental composition of winter wheat plants caused by the action of Megafol and retardants

In the conditions of the field experiments conducted during the 2015–2016 vegetation seasons retardants Medax Top, 1.0 l/ha (prohexadione-Са and mepiquat-chloride), appeared more effective than Terpal, 1.5 l/ha (mepiquat-chloride and ethephon), on field plots with high-yield varieties. Foliar application of Megafol promoted the productivity of winter wheat varieties Smuglyanka and Podolyanka and reduced the negative influence of retardants on the wheat plants in the vegetation seasons which were characterized by moisture deficit. The influence of modern retardants – prohexadione-Ca + mepiquat-chloride (Medax Top) and mepiquat-chloride + etefone (Terpal, both BASF, Germany) on the accumulation of some macro- and micronutrients in winter wheat plants was determined. The assays were performed on an ICP-MS Agilent 7700x mass spectrometer (Agilent Technologies, USA) with ICP-MS Mass Hunter WorkStation. Samples of winter wheat plants were taken in the phase of flowering and grain ripening. The samples were dried, homogenized, 0.400 gof weight was dissolved in ICP-grade nitric acid in the Milestone Start D (Milestone Inc., USA). All solutions were prepared on 1st class water (18 MΩ cm–1) obtained on the Scholar-UV Nex Up 1000 (Human Corporation, Korea) water purification system. The ICP-MS Complete Standard IV-ICPMS-71A was used as the external standard, and the internal standard was Sc, both of Inorganic Ventures, USA. According to the ICP-MS results of plant samples of winter wheat of Smuglylanka and Podolanka, it has been shown that, in conditions of wheat growing on light soils of Polissya, modern compositional retardants affect the ionome of plants during vegetation, as well as change the content of inorganic elements in the grain. It was found that winter wheat of middle-stem Podolyanka type, of the intensive type, reacted more responsively to retardant treatment than the short-stem-type highly intensive Smuglyanka type. At the same time, there was an increase in the content of nutrients in winter wheat of the Podolyanka variety. It should be noted that wheat grain of the Smuglyanka variety contained a significantly higher pool of macro- and trace elements than the Podolyanka variety. It was established that the treatment of winter wheat Podolyanka varieties by mepiquat-chloride and ethephon (Terpal, 1.5 l/ha) positively influenced the accumulation of potassium, magnesium and calcium and manganese, copper and zinc in the grain. We found that foliar application of compositions of amino acids simultaneously with retardants can reduce the negative action of PGR’s on formation of the harvest in conditions of drought and influence the maintenance of composition of inorganic elements in the plants and in the grain. The composition of retardants with the content of cyclohexadione derivative (Medax Top) also significantly influenced the changes in the content of inorganic elements in plants and grains. We note the significant increase in the content of magnesium in the leaves and in grain due to the action of Medax Top. These differences in reaction of winter wheat varieties to the action of retardants of the class of cyclohexadione are important for clarifying the systems of nutrition of crops in intensive growing technologies, especially in the conditions of drought and high temperatures. Reduction in the pools of a number of inorganic elements in plants, for example iron, by the action of retardants may be due to the constraints on the entry of these elements from the poor soils of the Polissya zone and should be compensated via foliar nutrition. Also, the peculiarities of the activity of plant growth regulators have been shown to indicate a close relationship between signal systems of plants and changes in ionome.

The Influence of Vanadium on Ferrite and Bainite Formation in a Medium Carbon Steel

The influence of vanadium additions on transformation kinetics has been investigated in a medium carbon forging steel. Using dilatometry to track transformation during continuous cooling or isothermal transformation, the impact of vanadium on both ferrite-pearlite and bainite has been quantified. Transmission electron microscopy and atom probe tomography have been used to establish whether vanadium was present in solid solution, or as clusters and precipitates. The results show that vanadium in solid solution has a pronounced retarding influence on ferrite-pearlite formation and that, unlike in the case of niobium, this effect can be exploited even during relatively slow cooling. The influence on bainite transformation was found to depend on temperature; an explanation in terms of the effect of vanadium on heterogeneous nucleation is tentatively proposed.

Electrokinetically induced thermofluidic transport of power-law fluids under the influence of superimposed magnetic field

This paper presents a theoretical analysis of non-Newtonian (power-law obeying) fluid in a narrow confinement subjected to the combined consequences of interfacial electrokinetics, rheology, and superimposed magnetic field. We devote special attention on the exploitation of magnetic field and power-law exponent, in the development of induced streaming potential and thermofluidic energy transfer characteristics over small scales. In an effort to do so, going beyond the Debye-Hückel limit, we first derive an expression for streaming potential by invoking the consequences of strong EDL (electrical double layer) interactions in the narrow fluidic passage and finite conductance of the Stern layer. In particular, we solve thermal energy transport equation with an illustrative case of classical uniform wall heat flux boundary and considering the volumetric heat generation effects due to viscous dissipation as well as Joule heating. Our results demonstrate that the applied magnetic field imparts a retarding influence on the induced streaming potential development, whereas, it results in enhancement of heat transfer rate. Moreover, additional influences of power law index show reduction in heat transfer as well as the streaming potential magnitude. We unveil the optimal combinations of power law index and the magnetic field which lead to the minimization of the global total entropy generation in the system. We believe that theoretical results presented in this research will be useful in the development of novel narrow fluidic energy efficient devices under electrokinetic modulation.

Тhe influence of retardants on the reduction of growth rate and the preservation of viability of sterile cultures

Тhe influence of retardants on the reduction of growth rate and the preservation of viability of sterile cultures

Influence of halloysite nanotubes and intumescent flame retardant on mechanical and thermal properties of 80/20 (wt/wt) PP/ABS blend and their composites in the presence of dual compatibilizer

Halloysite nanotubes (HNTs) and intumescent flame retardant (IFR)-filled 80/20 (wt/wt) polypropylene/acrylonitrile–butadiene–styrene (PP/ABS) blend and their composites in the presence of dual compatibilizer have been prepared using twin screw extruder followed by injection molding. There exists the formation of α- and β-form of PP crystals in addition to enhancement in crystallinity of PP phase by an addition of HNTs and IFR in 80/20 (wt/wt) PP/ABS blend and their composites in the presence of dual compatibilizer. In addition, scanning electron microscopy (SEM) reveals the formation of matrix-droplet morphology, and the dispersion of HNTs and IFR in 80/20 (wt/wt) PP/ABS blend and its composites in the presence of dual compatibilizer results in a refinement in matrix-droplet morphology. This has resulted in an enhancement in tensile and impact properties of HNTs- and IFR-filled 80/20 (wt/wt) PP/ABS blend and their composites in the presence of dual compatibilizer. Thermal stability also increases by an addition of HNTs and IFR in 80/20 (wt/wt) PP/ABS blend and their composites in the presence of dual compatibilizer due to formation of intumescent char.

Features of gas exchange and use of reserve substances in pumpkin seedlings in conditions of skoto- and photomorphogenesis under the influence of gibberellin and chlormequat-chloride

We investigated the effect of gibberellin and the antigibberellic agent chlormequat-chloride on gas exchange and use of reserve substances in pumpkin seedlings during germination in the light and in the dark. We established that an artificial strengthening or growth inhibition of pumpkin seedlings in conditions of skotomorphogenesis caused an increase in of respiration intensity. Gibberellin treatment increased the proportion of assimilation processes in carbon dioxide gas exchange of seedlings, and growth inhibition by retardant caused an increase in respiratory costs when the nutrition type switches in the light from heterotrophic to autotrophic. The formation by seedlings of the demand for reserve assimilates from cotyledons was largely determined by change of activity of subapical meristems, which is manifested in the acceleration of seed germination, enhancing of histogenesis for the actions of gibberellin and in the weakening of these processes under the influence of retardants. Reserve substances used both oil and nitrogen-containing compounds. The content of protein nitrogen in pumpkin cotyledons decreased more in the light than in the dark, moreover growth inhibition by the retardant slowed down and growth increase by gibberellin accelerated this process both in conditions of photomorphogenesis and skotomorphogenesis.

Influence of retardation and acceleration of setting time on the efficiency of water defluoridation by calcined gypsum

Fluoride ion (F−) removal technologies from water (defluoridation) suffer from cost and/or efficiency drawbacks. The hugely available low-cost calcined gypsum (plaster of paris) represents a material of choice, especially in the developing countries. Partially soluble calcined gypsum introduces Ca2+ and SO4 2− into the water. In this work, the influence of tartaric acid, paracetamol, polyvinyl alcohol and Zn/Al layered double hydroxide additives (either retarders or accelerators) on defluoridation of water by calcined gypsum was studied. These additives act as retarders to the calcined gypsum setting and, hence, delay or disturb the crystallization of gypsum, offering the time for the crystallization of fluoro-compounds containing calcium, fluoride, phosphate and silicate. The more retarded the setting time, the more the Ca2+ is introduced in the solution, and hence, the more efficient the defluoridation process. The values of ΔG 0 are negative for all additives, indicating the spontaneity of the fluoride removal process. The results of X-ray diffraction, Fourier transform infrared and scanning electron microscopy of the produced gypsum supported this interpretation.

Применение огнезащитных пропиточных композиций для снижения пожарной опасности деревянных конструкций с различными сроками эксплуатации

The article presents the results of a study on the development of fire-retardant impregnating compositions for reducing fire hazard of protecting wooden structures (WS) of different lifespan. Basic scientific notion in the present work, connected with the possibility of influence of fire retardants (fire retardants) on the formation of coal residue, its structure and properties within the first minutes of fire exposure with the aim of reducing fire hazard properties of WS is not only at the initial stage, but maintaining the thermal stability and the cohesiveness of WS in conditions of prolonged fire. The results of the study using thermal analysis showed that during the development and application of fire retardants for wood long life the defining characteristics are speed and the heat of oxidation of the coal residue. This is due to the specific behavior of the long-term operation wood under fire conditions. Designed compounds effectively reduce these characteristics. So the heat of coal oxidation residue for long - term operation wood (81 years) with the composition containing dimetilfosfit and modifying additives, is reduced to 1.27 times in comparison with coal modern wood. It is shown that with increasing period of operation of WS up to 200 years, the effectiveness of this flame retardant in the reduction of the characteristics of thermal analysis is preserved. It is determined that the flame retardants can have an impact on the formation of coal residue, its structure and properties and also to reduce heat effect (20-80 °C) throughout the experiment and intensity of WS charring (1.07-1.29 times) in the conditions of fire tests according to GOST 30403-2012, despite a small amount of flame retardant in the surface layer of the structure. The effectiveness of flame retardants is also evident in the reduction of ignition time by WS in standard temperature conditions of a fire. Fire-retardant treatment of WS compounds allows to increase the resistance of structures to flammability to 1.4-1.8 times. Mechanism of fire retardant effect is evident in change of main phases of wood thermal decomposition as well as in impact on the structure and properties of formed coal layer and it’s oxidizing capacity and heat effect in term of WS fire testing. This is extremely important because these characteristics are closely interrelated with the extent of thermal damage, charring, and the intensity of heat dissipation WS, which determine ultimately their fire danger and fire resistance.