The acoustic performance of floors plays a primary role in the total quality rating of a residential building. The sound insulation of lightweight frame floors, which are increasingly being used in housing, depends on a number of factors and technical details. In effect, the sound transmission scheme is distinctly more complicated than in the case of homogeneous massive partitions. The aim of the study was to develop effective insulating layers of lightweight floors intended for use in residential buildings. The floor system should satisfy legal requirements in terms of airborne and impact sound insulation. The research was based on laboratory measurements taken in a standard test facility. Ten different models of wood and metal floors were considered. The acoustic performance of their basic structure was insufficient; however, the application of effective floating floors and suspended ceilings improved it greatly and succeeded in potential meeting requirements and satisfying most inha... [more]

This paper aims at investigating the production of high quality briquettes from olive mill solid waste (OMSW) mixed with corn starch as a binder for energy production. For this purpose, different mass percentages of OMSW and binder were considered; 100%-0%, 90%-10%, 85%-15%, and 70%-30%, respectively. The briquetting process of the raw mixtures was carried out based on high pressures. Physico-chemical and mechanical characterizations were performed in order to select the best conditions for the briquettes production. It was observed that during the densification process, the optimal applied pressure increases notably the unit density, the bulk density, and the compressive strength. Mechanical characterization shows that the prepared sample with 15% of corn starch shows the best mechanical properties. Moreover, the corn starch binder affects quietly the high heating value (HHV) which increases from 16.36 MJ/Kg for the 100%-0% sample to 16.92 MJ/Kg for the 85%-15% sample. In addition, th... [more]

Biogas upgrading is a key operation for transforming raw biogas into valuable biomethane that can be used as fuel or transported through pipelines. Pressure swing adsorption (PSA) is one possible technique that can be used for upgrading. ZSM-5 with high silica/aluminum (Si/Al) ratio has a reasonable CO2/CH4 selectivity and an almost linear CO2 adsorption isotherm, which can reduce power consumption. Extrusion of zeolites uses Al-based binders which can result in a denaturation and in a decrease of Si/Al ratio, promoting a steeper CO2 isotherm and also impacting the water adsorption. In this work, we have extruded a ZSM-5 (with a Si/Al = 200) using only silica-based binder. Different samples were obtained using different extrusion paste compositions and operating conditions and their textural properties characterized. The mechanical strength of the samples as well as the CO2, CH4, and H2O adsorption equilibrium isotherms at 303−343 K were measured. Our results show that it is possible t... [more]

Latent heat thermal energy storage (LHTES) using phase change materials (PCM) is one of the most promising ways for thermal energy storage (TES), especially in lightweight buildings. However, accurate control of the phase transition of PCM is not easy to predict. For example, neglecting the hysteresis or the effect of the speed of phase change processes reduces the accuracy of simulations of TES. In this paper, the authors propose a new software module for EnergyPlus™ that aims to simulate the hysteresis of PCMs during the phase change. The new module is tested by comparing simulation results with experimental tests done in a climatic chamber. A strong consistency between experimental and simulation results was obtained, while a discrepancy error of less than 1% was obtained. Moreover, in real conditions, as a result of quick temperature changes, only a partial phase transformation of the material is often observed. The new model also allows the consideration of the case with partial p... [more]

The impact of using different nanostructured carbon materials (carbon nanofibers, carbon nanotubes, graphene oxide and activated carbon) as a support for Mo2C-based catalysts on the hydrodeoxygenation (HDO) of guaiacol was studied. To optimise the catalyst preparation by carbothermal hydrogen reduction (CHR), a thermogravimetric study was conducted to select the optimum CHR temperature for each carbon material, considering both the crystal size of the resulting β-Mo2C particles and the extent of the support gasification. Subsequently, catalysts were prepared in a fixed bed reactor at the optimum temperature. Catalyst characterization evidenced the differences in the catalyst morphology as compared to those prepared in the thermogravimetric study. The HDO results demonstrated that the carbon nanofiber-based catalyst was the one with the best catalytic performance. This behaviour was attributed to the high thermal stability of this support, which prevented its gasification and promoted a... [more]

The paper presents the results of an investigation into thin single- and triple-layer ZrO2-Sc2O3-based electrolytes prepared using the tape-casting technique in combination with promising electrodes based on La2NiO4+δ and Ni-Ce0.8Sm0.2O2-δ materials. It is shown that pressing and joint sintering of single electrolyte layers allows multilayer structures to be obtained that are free of defects at the layer interface. Electrical conductivity measurements of a triple-layer electrolyte carried out in longitudinal and transverse directions with both direct and alternating current showed resistance of the interface between the layers on the total resistance of the electrolyte to be minimal. Long-term tests have shown that the greatest degradation in resistance over time occurs in the case of an electrolyte with a tetragonal structure. Symmetrical electrochemical cells with electrodes fabricated using a screen-printing method were examined by means of electrochemical impedance spectroscopy. Th... [more]

In carbon storage activities, and in shale oil and gas extraction (SOGE) with carbon dioxide (CO2) as stimulation fluid, CO2 comes into contact with shale rock and its pore fluid. As a reactive fluid, the injected CO2 displays a large potential to modify the shale’s chemical, physical, and mechanical properties, which need to be well studied and documented. The state of the art on shale−CO2 interactions published in several review articles does not exhaust all aspects of these interactions, such as changes in the mechanical, petrophysical, or petrochemical properties of shales. This review paper presents a characterization of shale rocks and reviews their possible interaction mechanisms with different phases of CO2. The effects of these interactions on petrophysical, chemical and mechanical properties are highlighted. In addition, a novel experimental approach is presented, developed and used by our team to investigate mechanical properties by exposing shale to different saturation flu... [more]

The need for the development of new, advanced building materials increases every year, especially due to the necessary diminution of energy performance for building structures and for building production itself (including the production of building materials). Along with the energy performance problems in construction, the issue of CO2 emission associated with building and the production of building materials is also important. In the field of advanced thermal insulation materials, vacuum insulation panels (VIPs) give the best results. However, their high-energy performance and material consumption present a problem. This work represents an initial part of the development of alternative insulators, based on agricultural and textile industry waste usable in the production of VIP. This article recapitulates basic knowledge regarding key thermal insulation properties of developed insulators and their fire reactions, which impact possible usage in building structures.

Geopolymers are considered to alternatives to Portland cement, providing an opportunity to exploit aluminosilicate wastes or co-products with promising performances in the construction sector. This research is aimed at investigating the strength of fly-ash-geopolymers of different ages. The effect of granulated blast furnace slag (GGBFS) as a partial replacement of fly ash (FA) on the tensile (ft) and compressive strength (fc), as well as the modulus of elasticity, is investigated. The main advantage of the developed geopolymer mixes containing GGBFS is their ability to set and harden at room temperature with no need for heating to obtain binding properties, reducing the energy consumption of their production processes. This procedure presents a huge advantage over binders requiring heat curing, constituting a significant energy savings and reduction of CO2 emissions. It is found that the development of strength strongly depends on the ratio of fly-ash to granulated blast furnace slag.... [more]

With many emerging applications such as chemical reactions and ultrasound therapy, acoustic cavitation plays a vital role in having improved energy efficiency. For example, acoustic cavitation results in substantial enhancement in the rates of various chemical reactions. In this regard, an applied acoustic field within a medium generates acoustic streaming, where cavitation bubbles appear due to preexisting dissolved gas in the working fluid. Upon cavitation inception, bubbles can undergo subsequent growth and collapse. During the last decade, the studies on the effects of different parameters on acoustic cavitation such as applied ultrasound frequency and power have been conducted. The bubble growth and collapse mechanisms and their distribution within the medium have been classified. Yet, more research is necessary to understand the complex mechanism of multi-bubble behavior under an applied acoustic field. Various parameters affecting acoustic cavitation such as surface roughness of... [more]

This study investigates how the petrographic features of Klepa Nafpaktias sandstones affect their behavior in construction applications such as concrete, in environmental applications such as energy storage as well as whether they are suitable for the above uses. For achieving this goal, sandstones (ten samples) were collected in order to study their petrographic characteristics using petrographic microscope and GIS software, as well as their basic physical, mechanical and physicochemical properties were also examined. Concrete specimens (C25/30) were made according to international standards including the investigated aggregate rocks in various grain sizes. Various sandstones were tested and classified in three district groups according to their physicomechanical features as well as to their petrographic and microtopographic characteristics. Concrete strength’s results determined the samples into three groups which are in accordance with their initial classification which was relative... [more]

The abundant reserve of shale gas in Sichuan Basin has become a significant natural gas component in China. To achieve efficient development of shale gas, it is necessary to analyze the stress state, pore pressure, and reservoir mechanical properties such that an accurate geomechanical model can be established. In this paper, Six wells of Neijiang-Dazu and North Rongchang (NDNR) Block were thoroughly investigated to establish the geomechanical model for the study area. The well log analysis was performed to derive the in-situ stresses and pore pressure while the stress polygon was applied to constrain the value of the maximum horizontal principal stress. Image and caliper data, mini-frac test and laboratory rock mechanics test results were used to calibrate the geomechanical model. The model was further validated by comparing the model prediction against the actual wellbore failure observed in the field. It was found that it is associated with the strike-slip (SS) stress regime; the or... [more]

In this study, lignin with fine structures and facile enzymatic saccharifying residue were successively dissociated based on the lignin-first biomass deconstruction strategy. In the lignin-first process, aldehyde-protected lignin fractions were firstly isolated by acid-catalyzed dioxane extraction in the presence of formaldehyde (FA) and acetaldehyde (AA) and then analyzed by advanced nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC). The optimized hydrogenolysis of the extracted lignin (LFA and LAA) resulted in a high yield (42.57% and 33.00%) of lignin monomers with high product selectivity (mainly 2,6-dimethoxy-4-propylphenol) (39.93% and 46.61%). Moreover, the cellulose-rich residues were saccharified into fermentable glucose for bioethanol production. The glucose yield of the substrate (RAA) reached to 75.12%, which was significantly higher than that (15.4%) of the substrate (RFA). In short, the lignin-first biomass deconstruction by adding AA i... [more]

The paper presents the results of tests of the shear strength of the ash−slag mixture taken from the landfill located in Kraków (Poland) and the interfacial friction resistance at the contact between the ash−slag mixture and woven or nonwoven geotextiles. The tests were carried out in a direct shear apparatus on samples with and without water saturation. The samples for testing were formed in the apparatus box at the optimum moisture by compacting them to IS = 0.90 and 1.00. The test results reveal that the shear strength parameters of the ash-slag mixture were large. It was stated the significant influence of the compaction, the growth of which has resulted in an increase in the angle of internal friction (from 7% to 9%) and cohesion (from 60% to 97%). Whereas the saturation of the samples reduced the shear strength parameters (from 4% to 6%, of the internal friction angle and 30% to 43% of cohesion). The values of the interfacial friction resistance at the contact between the ash−sla... [more]

In search of guaranteeing global energy requirements, waste from different agricultural, forestry and industrial sources is presented as a renewable and sustainable energy source. The manufacture of solid fuels from biomass based on the densification of this to improve its mechanical and energy properties is one of the mechanisms of viable energy production from the technical-economic point of view. The biomass mixture is one of the topics currently researched, in which various factors can affect the final behavior of the briquettes. In this research the influence on the mechanical properties of briquettes obtained from the mixture between two biomasses is studied: rice husk and pine sawdust. A mixed factorial experimental factorial design is used, in which the process temperature, the proportion of the rice husk biomass over the total mass, and the compaction time are defined as experimental factors. Experimental statistical models are obtained that partially explain the behavior of s... [more]

The enzymatic hydrolysis of cellulose from biomass feedstock in the sugar-based biorefinery chain is penalized by enzyme cost and difficulty to approach the theoretical maximum cellulose conversion degree. As a consequence, the process is currently investigated to identify the best operating conditions with reference to each biomass feedstock. The present work reports an investigation regarding the enzymatic hydrolysis of apple pomace (AP). AP is an agro-food waste largely available in Europe that might be exploited as a sugar source for biorefinery purposes. A biomass pre-treatment step was required before the enzymatic hydrolysis to make available polysaccharides chains to the biocatalyst. The AP samples were pre-treated through alkaline (NaOH), acid (HCl), and enzymatic (laccase) delignification processes to investigate the effect of lignin content and polysaccharides composition on enzymatic hydrolysis. Enzymatic hydrolysis tests were carried out using a commercial cocktail (Cellic... [more]

Increasing energy prices make space heating more expensive every year in The Organisation for Economic Co-operation and Development (OECD) member countries. Thermochemical heat storage systems (THSS) can be used to reduce residential energy consumption for space heating and to control humidity. Utilizing compressed thermochemical pellets as heat storage materials is a way to increase volumetric energy storage capacity and to improve the performance of the THSS. In this work, expanded natural graphite (ENG), activated carbon (AC), strontium bromide, and magnesium sulphate were mixed in different mass ratios and compressed under applied pressures in a range of 0.77 to 5.2 kN⋅mm−2 to form composite pellets with a diameter of 12 and 25 mm, respectively, and a thickness from 1.5 to 25 mm. These pellets were characterized using thermogravimetric analysis and differential scanning calorimetry. Cyclic tests of hydration at 20 °C and dehydration at 85 °C were conducted to investigate changes in... [more]

Recycled polylactic acid (PLAr) was reinforced with treated nanocellulosic hemp fibers for biocomposite fabrication. Cellulosic fibers were extracted from hemp fibers chemically and treated enzymatically. Treated nanocellulosic fibers (NCF) were analyzed by Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Biocomposite fabrication was done with PLAr and three concentrations of treated NCF (0.1%, 0.25%, and 1% (v/v)) and then studied for thermal stability and mechanical properties. Increased thermal stability was observed with increasing NCF concentrations. The highest value for Young’s modulus was for PLAr + 0.25% (v/v) NCF (250.28 ± 5.47 MPa), which was significantly increased compared to PLAr (p = 0.022). There was a significant decrease in the tensile stress at break point for PLAr + 0.25% (v/v) NCF and PLAr + 1% (v/v) NCF as compared to control (p = 0.006 and 0.002, respectively). No significant difference was observed between treatments... [more]

This study introduces a new framework to quantify the wettability of powdered carbonate rock from existing correlations between zeta potential and contact angle. The new framework has the potential to be faster and cheaper than conventional approaches and could increase confidence in surface wetting quantification, since the results are insensitive to the inherent heterogeneity of rock surfaces. The obtained results from experiments were used to develop a set of equations for determining the carbonate rock contact angle from streaming potential data. The equations were validated for the evaluation of changes in the wettability of carbonate rock using different stearic acid oily solutions. The contact angles calculated from the proposed equations were then compared with measured values on the calcite surface. The results show that the proposed framework was able to quantify the wettability of carbonate rock with an acceptable range of error of about 4%−14%.

Detailed insight into electrochemical reaction mechanisms and rate limiting steps is crucial for targeted optimization of solid oxide fuel cell (SOFC) electrodes, especially for new materials and processing techniques, such as Ni/Gd-doped ceria (GDC) cermet anodes in metal-supported cells. Here, we present a comprehensive model that describes the impedance of porous cermet electrodes according to a transmission line circuit. We exemplify the validity of the model on electrolyte-supported symmetrical model cells with two equal Ni/Ce0.9Gd0.1O1.95-δ anodes. These anodes exhibit a remarkably low polarization resistance of less than 0.1 Ωcm2 at 750 °C and OCV, and metal-supported cells with equally prepared anodes achieve excellent power density of >2 W/cm2 at 700 °C. With the transmission line impedance model, it is possible to separate and quantify the individual contributions to the polarization resistance, such as oxygen ion transport across the YSZ-GDC interface, ionic conductivity wit... [more]

Photoelectrochemical water splitting is considered as a long-term solution for the ever-increasing energy demands. Various strategies have been employed to improve the traditional TiO2 photoanode. In this study, TiO2 nanorods were decorated by graphitic carbon nitride (C3N4) derived from different precursors such as thiourea, melamine, and a mixture of thiourea and melamine. Photoelectrochemical activity of TiO2/C3N4 photoanode can be modified by tuning the number of precursors used to synthesize C3N4. C3N4 derived from the mixture of melamine and thiourea in TiO2/C3N4 photoanode showed photocurrent density as high as 2.74 mA/cm2 at 1.23 V vs. RHE. C3N4 synthesized by thiourea showed particle-like morphology, while melamine and melamine with thiourea derived C3N4 yielded two dimensional (2D) nanosheets. Nanosheet-like C3N4 showed higher photoelectrochemical performance than that of particle-like nanostructures as specific surface area, and the redox ability of nanosheets are believed t... [more]

Herein, we report thin films’ characterizations and photovoltaic properties of an organic semiconductor zinc phthalocyanine (ZnPc). To study the former, a 100 nm thick film of ZnPc is thermally deposited on quartz glass by using vacuum thermal evaporator at 1.5 × 10−6 mbar. Surface features of the ZnPc film are studied by using scanning electron microscope (SEM) with in situ energy dispersive x-ray spectroscopy (EDS) analysis and atomic force microscope (AFM) which reveal uniform film growth, grain sizes and shapes with slight random distribution of the grains. Ultraviolet-visible (UV-vis) and Fourier Transform Infrared (FTIR) spectroscopies are carried out of the ZnPc thin films to measure its optical bandgap (1.55 eV and 3.08 eV) as well as to study chemical composition and bond-dynamics. To explore photovoltaic properties of ZnPc, an Ag/ZnPc/PEDOT:PSS/ITO cell is fabricated by spin coating a 20 nm thick film of hole transport layer (HTL)—poly-(3,4-ethylenedioxythiophene) poly(styren... [more]

This paper investigates the use of Li-LSX-zeolite catalyst over three regeneration cycles in presence of non-treated and acid pre-treated Isochrysis sp. microalgae. The spent and regenerated catalysts were characterised by surface analysis, elemental analysis (EA), SEM-EDS, and XRD to correlate their properties with the bio-oil yield and quality. The acid pre-treatment removed alkali metals, reducing gas yield in favour of bio-oil, but, at the same time, led to catalyst deactivation by fouling. Differently, the non-treated microalgae resulted in a bio-oil enriched in C and H and depleted in O, compared to the pre-treated ones, denoting higher deoxygenation activity. After 3 pyrolysis/regeneration cycles, the analyses suggest that there are no major changes on catalyst using non-treated microalgae. Regeneration at 700 °C has been shown to be able to remove most of the coke without damaging the Li-LSX zeolite structure. In summary, Li-LSX zeolite was effective in maintaining deoxygenatio... [more]

The incorporation of phase change materials (PCM) in construction components has become an alternative to reduce the effect of thermal loads in buildings with low thermal inertia. This study put together the effective heat storage capacity of an organic phase change material (O-PCM, octadecane) with the construction and production potential of Pinus radiata in Chile. The wood is impregnated with octadecane by using the Bethell method, showing that it has good retention of the impregnator, and that its size was not modified. Differential scanning calorimetry analysis (DSC) showed that the composite material could achieve fusion enthalpy values from 36 (20.8 MJ/m3) to 122 J/g (108.9 MJ/m3). The transient line heat source method used, indicated that impregnation of Pinus radiata with octadecane increases its specific heat at temperatures from 15 to 20 °C, while its thermal conductivity decreases in the radial and the tangent directions, and increases in the longitudinal direction, showing... [more]

Due to the working condition of low-voltage cabling from the mining flameproof movable substation to the loads of the mining face being poor, it is easy to cause various external mechanical damages to the cable sheaths. Furthermore, a single-phase earth leakage fault or short-circuit fault can occur when the low-voltage cable sheaths are damaged, and electric sparks caused by these faults can lead to a gas explosion. As the gas detonation time caused by the above faults is usually more than 5 ms, the high-speed interruption solid-state switch which controls the cables must cut off the current within 3 ms. This requires the action time of the solid-state switch to be less than 1 ms, and at the same time, the sampling and calculation time of the relay protection must be less than 2 ms. Based on these problems, this paper proposes the use of a high-speed solid-state circuit breaker (SSCB) topology at the neutral point of transformer, and analyzes the conduction mechanism and shut-off mech... [more]