A Novel Method for Calcium Carbonate Deposition in Wood That Increases Carbon Dioxide Concentration and Fire Resistance

In this study, a novel method for calcium carbonate deposition in wood that increases carbon dioxide concentration and fire resistance is proposed. The method promoted the mineralization of radiata pine wood microstructure with calcium carbonate by using a process consisting in the vacuum impregnation of wood with a calcium chloride aqueous solution and the subsequent sequential diffusion of gaseous ammonium and carbon dioxide. In the most favorable conditions, the method yielded a weight gain of about 20 wt.% due to mineralization, which implied the accumulation of 0.467 mmol·g−1 of carbon dioxide in the microstructure of wood. In addition, a weight gain of about 8% was sufficient to provide fire resistance to a level similar to that achieved by a commercially available fire-retardant treatment. The feasibility of retaining carbon dioxide directly inside the wood microstructure can be advantageous for developing wood products with enhanced environmental characteristics. This method can be a potential alternative for users seeking materials that could be effective at supporting a full sustainable development.

Synthesis and Characterization of New nano catalyst Mo-Ni /TiO2- γAl2O3 for Hydrodesulphurization of Iraqi Gas Oil

A new nano-sized NiMo/TiO2-γ-Al2O3 was prepared as a Hydrodesulphurization catalyst for Iraqi gas oil with sulfur content of 8980 ppm, supplied from Al-Dura Refinery. Sol-gel method was used to prepare TiO2- γ-Al2O3 nano catalyst support with 64% TiO2, 32% Al2O3, Ni-Mo/TiO-γ-Al2O3 catalyst was prepared under vacuum impregnation conditions to loading metals with percentage 3.8 wt.% and 14 wt.% for nickel and molybdenum respectively while the percentage for alumina, and titanium became 21.7, and 58.61 respectively. The synthesized TiO2- γ-Al2O3 nanocomposites and Ni-Mo /TiO2- γ-Al2O3 Nano catalyst were then characterized by XRD, AFM, and BET surface area, SEM, XRF, and FTIR. The performance of the synthesized catalyst for removing sulfur compounds was conducted through the pilot HDS laboratory unit, various temperatures range 275oC to 375°C, LHSV 1 h-1 were studied; moreover, the effect of LHSV 1 to 4 h-1 on the percentage of sulfur removal was also studied at the temperature of the best removal with constant pressure 35 bar and H2/HC ratio 200cm3/200cm3. The sulfur content results generally revealed that there was a substantial decrease at all operating conditions used, while the maximum sulfur removal was 87.75% in gas oil on Ni-Mo/TiO2-γ-Al2O3 catalyst at temperature 375˚C and LHSV 1h-1.

Evaluation of Energy Performance and Thermal Comfort Considering the Heat Storage Capacity and Thermal Conductivity of Biocomposite Phase Change Materials

The application of phase change materials (PCMs) has been verified as an effective strategy for improving energy efficiency and reducing greenhouse gas emissions. Biocomposite PCMs (Bc-PCM) exhibit large latent heat, chemical stability, and a wide temperature range. In this study, thermal conductivity improved Bc-PCM (TBc-PCM) was made via vacuum impregnation with graphene nanoplatelets (GNPs). Chemical stability analysis and thermal performance analyses of the Bc-PCM and TBc-PCM were carried out as well as building energy simulations and thermal comfort analyses. Our results show Bc-PCM showed a higher heat storage capacity and enthalpy value compared to TBc-PCM. TBc-PCM exhibited a 378% increase in thermal conductivity compared to Bc-PCM. Building energy simulation results revealed that annual heating and cooling energy consumption decreased as the thickness of the PCM layer increased. In addition, the Bc-PCM with a larger PCM capacity was more effective in reducing energy consumption during the heating period. On the other hand, the cooling energy reduction effect was greater when TBc-PCM with high thermal conductivity was applied because of the high heat transfer during the cooling period. Thermal comfort evaluation revealed it was more comfortable when PCM was applied.

Configuration of Multifunctional Polyimide/Graphene/Fe3O4 Hybrid Aerogel-Based Phase-Change Composite Films for Electromagnetic and Infrared Bi-Stealth

Electromagnetic (EM) and infrared (IR) stealth play an important role in the development of military technology and the defense industry. This study focused on developing a new type of multifunctional composite film based on polyimide (PI)/graphene/Fe3O4 hybrid aerogel and polyethylene glycol (PEG) as a phase change material (PCM) for EM and IR bi-stealth applications. The composite films were successfully fabricated by constructing a series of PI-based hybrid aerogels containing different contents of graphene nanosheets and Fe3O4 nanoparticles through prepolymerizaton, film casting, freeze-drying, and thermal imidization, followed by loading molten PEG through vacuum impregnation. The construction of PI/graphene/Fe3O4 hybrid aerogel films provides a robust, flexible, and microwave-absorption-functionalized support material for PEG. The resultant multifunctional composite films not only exhibit high microwave absorption effectiveness across a broad frequency range, but also show a good ability to implement thermal management and temperature regulation under a high latent-heat capacity of over 158 J/g. Most of all, the multifunctional composite films present a wideband absorption capability at 7.0–16.5 GHz and a minimum reflection loss of −38.5 dB. This results in excellent EM and IR bi-stealth performance through the effective wideband microwave absorption of graphene/Fe3O4 component and the thermal buffer of PEG. This study offers a new strategy for the design and development of high-performance and lightweight EM–IR bi-stealth materials to meet the requirement of stealth and camouflage applications in military equipment and defense engineering.

Investigation of technology schemes for the production of cast composite functional materials

Obtaining and using ligatures, modifiers and deoxidizers to obtain structural alloys of a given composition and properties in metallurgy and foundry is an important production task. One of the existing developments in the field of technologies for the preparation of functional composites on a matrix basis for non-ferrous and ferrous alloys is the combination of solid filler with a melt of an active metal binder. At that, from the filler material, which is selected from the group comprising iron, nickel, titanium, silicon, boron, manganese, first a porous workpiece of a given geometric shape with a technological total pore volume is formed, then it is heated to a temperature corresponding to the liquidus temperature of the active binder, the heating being carried out in a gas inert medium, after which the heated workpiece is impregnated with the melt of this binder by forced infiltration of the melt into the pores of the workpiece under pressure, mainly by the method of liquid stamping. The task of the study was to expand the scope of use of composites, to create a single flexible universal, and at the same time, simplified technology that will provide an opportunity to obtain a wide range of diverse in composition and service characteristics of deoxidizers, modifiers and ligatures for non-ferrous and ferrous alloys. The developed technology, based on vacuum impregnation (suction) of the matrix alloy through porous filler, makes it possible to obtain new functional metal-matrix composite materials of a given composition for use as inexpensive ligatures, modifiers and deoxidizers in metallurgical processes, as well as to simplify and make their use safe. The proposed method for obtaining ligatures, modifiers and deoxidizers provides a possibility of their industrial serial production and is easy to perform, and also reduces the cost of the metallurgy product obtained with their application by increasing the effective content of active components and their more complete assimilation, which reduces the consumption of scarce and expensive materials.

Effect of Vacuum Impregnation with Sucrose and Plant Growth Hormones to Mitigate the Chilling Injury in Spinach Leaves

Vacuum impregnation (VI) has been immensely used in modifying the physicochemical properties, nutritional values and sensory attributes of fruits and vegetables. However, the metabolic consequences of the plant tissue upon impregnation have not been profoundly explored although shelf life is strongly dependent on this factor. In this study, spinach leaves were impregnated with salicylic acid (SA), γ-aminobutyric acid (GABA) and sucrose to improve its quality and storage ability by reducing the chilling injury through the improvement of proline content. The spinach leaves were stored at 4 °C for 7 days and were analyzed at 12 h interval. Upon 1 day of impregnation, the proline content in GABA, sucrose and SA impregnated leaves was increased by 240%, 153% and 103%, respectively, while in non-impregnated leaves, the proline content was decreased by 23.8%. The chlorophyll content of GABA impregnated leaves exhibited the lowest reduction (49%) followed by sucrose (55%) and SA (57%); meanwhile, non-impregnated leaves reduced 80% of chlorophyll content at the end of storage. Sensory evaluation showed that GABA, sucrose and SA impregnated leaves respectively, obtained higher score in terms of freshness, color, texture and overall appearance as compared to non-impregnated leaves.