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Wood impregnated with a multicomponent mixture of fatty acids as a bio-based phase change material (BPCM) to improve its thermal characteristics was studied. The studied wood/BPCM composites can be used as internal elements in buildings for energy storage. Scots pine and beech sapwood were impregnated with a multicomponent mixture of linoleic acid and coconut oil fatty acids at a ratio of 20:80. Leakage test was conducted and revealed that the maximum leakage for pine and beech were 9 and 8%, respectively. Light microscopy was employed to demonstrate the distribution of the BPCM in the wood structure. Rays in both pine and beech wood served as pathways for impregnation of the BPCM to partly fill the tracheid lumens (pine) and vessels (beech). Thermal characterization of the studied samples employed T-history and DSC methods, concluding that the impregnated wood had significant thermal mass, ability to store excessive energy in terms of latent heat and keep the temperature constant for long time. The specific heat capacity of the impregnated samples was 4–5 J g−1 K−1 i.e., higher than that of the untreated control samples of ca. 2 J g−1 K−1. The thermal conductivity of the samples before and after the impregnation was measured using heat flow meter method and the results showed that the untreated beech wood had higher thermal conductivity compared to pine and the parameter improved when the cell lumens were filled with the BPCM. Scots pine wood with to 80% mass percentage gain (MPG) after impregnation demonstrated an increment in thermal conductivity of 33% while Scots pine and beech with 43 and 38% MPG demonstrated an increase of the conductivity with 8 and 11%, respectively. [ABSTRACT FROM AUTHOR]

The use of lignocellulosic fibers into polymer matrices gained attention of the researchers and brought substantial research. The main objective of this research work is to determine the thermal characteristics and hygrothermal aging of untreated and surface modified Agave Cantala plant fiber‐reinforced polylactide composites. Cellulosic fibers were extracted from the fleshy leaves of the plant by water and mechanical retting processes. The extracted fibers were treated with trimethoxy methyl silane and fabrication of the composites was done using matched die molding method. These composites are characterized by thermo‐gravimetry analysis, Fourier transform infrared spectroscopy, X‐ray diffraction study, hygrothermal aging, energy dispersive X‐ray spectroscopy and field emission scanning electron microscopy analysis. The results showed the trimethoxy methyl silane treated A. Cantala treated fiber reinforced composites exhibiting better thermal, hygrothermal, and morphological behavior. [ABSTRACT FROM AUTHOR]

The manufacturing technology of historical mortars from the Roman to Medieval period apparently has not undergone evolutions. As reported in the literature, a quality decrease in the raw material occurred after the fall of the Roman Empire. During the Roman Age, the mortars presented the requirements of long durability due to hydraulic characteristics, and in later times, the production has only partially maintained the ancient requirements. To focus on the different production technologies between Roman and Medieval mortar, this research presents the case study of San Saturnino Basilica (Italy), where an archaeological mortar stratigraphy from Roman to Middle Ages is well preserved. An archaeometric characterization was performed to compare the mortars of the Roman period with the mortars of the Medieval period collected from the case-study monument. This comparison was carried out by measuring some physical-mechanical, mineralogical, petrographic and thermal features that give more information about the durability and resistance to mechanical solicitations and weathering. After the characterizations, contrary to what is reported in the bibliography, a better quality of Medieval materials than Roman ones is pointed out. This has been highlighted by higher hydraulicity, mechanical performance, and a more appropriated particle-size distribution of aggregates.

In recent years, there has been a growing interest in effectively managing agro-industrial waste. One promising approach that has gained attention is exploring this waste to develop new composite materials, especially polymeric materials, with diverse applications across various industries. This study focuses on comprehending the physical and thermal properties of fibrous residues derived from achira (Canna edulis Ker). To achieve this, several analyses, including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier transform infrared spectrometry (FTIR), have been conducted. Additionally, parameters such as moisture percentage, moisture absorption, bulk density, and lignin percentage have been calculated. The results indicate similarities between achira fibers and other characterized fibers, such as bamboo and other natural fibers studied in scientific research. Based on these findings, it is evident that integrating achira fibers into polymeric matrices is a feasible option. The results of this research offer an opportunity to utilize these materials and contribute to the advancement and strengthening of the recycled raw materials market, promoting sustainability and the circular economy.

• Temperature based measurement of incident IR intensity in free convection. • Two dry and one wet surface yield agreeably (∼10 % deviation) similar results. • IR camera distinguishes thermal boundary layer and a hot plume. • Low response time finds real time application to areas like in building management. The study aims to characterize external IR heating sources, operating in free convection atmosphere, qualitatively and quantitatively for various applications. It employs non-invasive IR thermography to measure steady-state irradiations from a ceramic IR heater at variable voltages (60–150 V) using the surface energy budget (SEB) method which relies on only two measured parameters (surface and ambient temperature). The free convection heat transfer from the plate is demarcated between the thermal boundary layer (TBL) and buoyant plume-dominated region by temperature histogram tool. Nearly 78 ± 5 % of the plate area is occupied by the hot plume(s) in the studied voltage range. Estimated irradiation agrees fairly well with one another (within ± 10 %). Additionally, the time response of the plate was measured to be ∼ 120 s. This fast response can be made even faster, by reducing the thermal mass, eventually leading to low-cost IR sensors. [ABSTRACT FROM AUTHOR]

Maintenance of adequate thermal properties is critical for correct operation of a gas foil bearing. In this work, the authors present the results of the experimentally conducted thermal characterization of a prototype installation of the bearing. A novel method of temperature identification, based on integrated thermocouples readings, has been employed to determine the thermal properties of the specialized sensing top foil mounted in the tested bearing. Two measurement campaigns have been subsequently completed, applying freely-suspended and two-node support configurations, to gather complementary knowledge regarding the bearing's operation. Apart from the rotational speed and temperature field measurements, the authors have also studied the friction torque and the shaft's journal trajectories based on its radial displacements. The temporal courses for the above-mentioned quantities have enabled inference on the effects present during run-up, run-out and stable state operation at a constant speed. As confirmed, the applied distribution of the integrated sensors allows for temperature readings on the entire outer surface of the foil, and therefore, provides useful data for the bearing characterization. The work is concluded with presentation of the recommended directions regarding future improvements of the proposed measurement technique and more comprehensive study of the bearing's characteristics. [ABSTRACT FROM AUTHOR]

With growing environmental concerns over synthetic polymers, natural polymeric materials, such as hemicellulose, are considered a good sustainable alternative. Curaua fibers could be an excellent source of biopolymer as they have a relatively high hemicellulose content (15 wt%) and only a small amount of lignin (7 wt%). In this work, hemicellulose was extracted by an alkaline medium using KOH and the influence of the alkali concentration, temperature, and time was studied. A hemicellulose film was produced by water casting and its mechanical, thermal, and morphological properties were characterized. The results show that the best method, which resulted in the highest hemicellulose yield and lowest contamination from lignin, was using 10% (w/v) KOH concentration, 25 °C, and time of 3 h. The hemicellulose film exhibited better thermal stability and elongation at break than other polymeric films. It also exhibited lower rigidity and higher flexibility than other biodegradable polymers, including polylactic acid (PLA) and polyhydroxybutyrate (PHB). [ABSTRACT FROM AUTHOR]

Polymerization kinetics as well as thermal properties of acrylic copolymers containing Isobornylacrylate- (IBOA) and 2-Ethylhexylacrylate- (2-EHA) units were investigated. Poly(IBOA-co-2-EHA) samples were synthesized via free radical photopolymerization/crosslinking reactions of IBOA and 2-EHA, in the presence of 1,6-hexanedioldiacrylate (HDDA) as crosslinking agent, to obtain chemically crosslinked polymer networks. High conversion rates of the acrylic double bonds of the monomers were obtained from investigation of the polymerization kinetics by infrared spectroscopy. Analysis of the thermal properties using differential scanning calorimetry revealed the appearance of a single glass transition of Poly(IBOA-co-2-EHA) over a large range of temperatures comprised between 208 and 321 K, depending on monomer composition. The evolution of the glass transition temperature was rationalized by applying the Fox, Gordon Taylor, and Brekner-Schneider-Cantow models, revealing presumably the existence of hydrogen bonding interaction involving the carbonyl groups of the acrylates. Several degradation processes were observed by thermogravimetrical analysis, especially that of the isobornylene group at low temperature followed by the degradation of the carbon backbone at higher temperatures. Increasing IBOA content leads to a higher thermal stability of Poly(IBOA-co-2-EHA). Each degradation step could be characterized separately exhibiting activation energies which strongly depend on the degradation time of each step. [ABSTRACT FROM AUTHOR]

Positively charged NCs of TZP (0.1%, w/v) for ocular use were prepared by the antisolvent precipitation method. TZP is a novel 5-Hydroxymethyl-Oxazolidinone class of antibiotic and is effective against many drug-resistant bacterial infections. Even the phosphate salt of this drug is poorly soluble, therefore the NCs were prepared for its better solubility and ocular availability. P188 was found better stabilizer than PVA for TZP-NCs. Characterization of the NCs including the particle-size, PDI, and ZP by Zeta-sizer, while morphology by SEM indicated that the preparation technique was successful to get the optimal sized (151.6 nm) TZP-NCs with good crystalline morphology. Mannitol (1%, w/v) prevented the crystal growth and provided good stabilization to NC1 during freeze-drying. FTIR spectroscopy confirmed the nano-crystallization did not alter the basic molecular structure of TZP. DSC and XRD studies indicated the reduced crystallinity of TZP-NC1, which potentiated its solubility. An increased solubility of TZP-NC1 (25.9 µgmL−1) as compared to pure TZP (18.4 µgmL−1) in STF with SLS. Addition of stearylamine (0.2%, w/v) and BKC (0.01%, w/v) have provided cationic (+29.4 mV) TZP-NCs. Redispersion of freeze-dried NCs in dextrose (5%, w/v) resulted in a clear transparent aqueous suspension of NC1 with osmolarity (298 mOsm·L−1) and viscosity (21.1 cps at 35 °C). Mannitol (cryoprotectant) during freeze-drying could also provide isotonicity to the nano-suspension at redispersion in dextrose solution. In vitro release in STF with SLS has shown relatively higher (78.8%) release of TZP from NC1 as compared to the conventional TZP-AqS (43.4%) at 12 h. TZP-NC1 was physically and chemically stable at three temperatures for 180 days. The above findings suggested that TZP-NC1 would be a promising alternative for ocular delivery of TZP with relatively improved performance. [ABSTRACT FROM AUTHOR]

A typical method for measuring the radial thermal conductivity of cylindrical objects is the pipe method. This method introduces a heating wire in combination with standard thermocouples and optical Fiber Bragg grating temperature sensors into the core of a cell. This experimental method can lead to high uncertainties due to the slightly varying setup for each measurement and the non-homogenous structure of the cell. Due to the lack of equipment on the market, researchers have to resort to such experimental methods. To verify the measurement uncertainties and to show the possible range of results, an additional method is introduced. In this second method the cell is disassembled, and the thermal conductivity of each cell component is calculated based on measurements with the laser flash method and differential scanning calorimetry. Those results are used to numerically calculate thermal conductivity and to parameterize a finite element model. With this model, the uncertainties and problems inherent in the pipe method for cylindrical cells were shown. The surprising result was that uncertainties of up to 25% arise, just from incorrect assumption about the sensor position. Furthermore, the change in radial thermal conductivity at different states of charge (SOC) was measured with fully functional cells using the pipe method. [ABSTRACT FROM AUTHOR]

The recovery and storage of process heat in industrial applications are some of the key factors to improve the sustainability and reliability of high temperature applications. In this sense, one of the main drawbacks is focused on the selection of proper thermal energy storage (TES) materials. This paper performs a full characterization of four phase change storage materials (PCM), KOH, LiOH, NaNO3 and KNO3, which are proposed for storage applications between 270 and 500 °C, according to the results obtained through differential scanning calorimeter and thermogravimetric analysis. One of the main innovations includes the corrosive evaluation of these materials in a promising alumina forming alloy (OC4), close to their corresponding phase change temperature during 500 h. The physicochemical properties obtained confirm the optimal use of NaNO3 and KNO3 and recommend the use, with caution, of KOH, due to its higher corrosive potential. FeCr2O4, NiCr2O4 and FeAl2O4 were the main protective spinels formed in the alloy surface, however, the cross-section study in the alloy immersed in KOH, revealed a non-uniform behavior, presenting some cracks and spallation in the surface. On the other hand, the proposal of LiOH was disregarded since it presents a narrow operation temperature range between melting and solidification point. [ABSTRACT FROM AUTHOR]

This work presents the experimental measurements and analysis of high-temperature electric and acoustic characterization of ferroelectric film bulk acoustic resonators (FBARs) based on sputtered aluminum scandium nitride (Al0.7 Sc0.3N) films. We recently reported a decreasing trend of the coercive field versus temperature and observed a three-fold reduction of the coercive field from 3MV/cm at room temperature to 1MV/cm at 600K. This work further studies the detailed electro-acoustic properties of Al0.7 Sc0.3 N thin films and FBARs at elevated temperatures. Such studies are critical given the high-power operation and self-heating issues related to 5G acoustic filters. Here, the polarization-dependent capacitance behavior of the metal-ferroelectric-metal (MFM) capacitor is studied in detail at various temperatures up to 600K. At 600K, we measured the DC I-V curves and showed clear resistance switching at a reduced voltage of ~100 V compared to room temperature. Furthermore, the resonance frequency of FBARs is tested at varying temperatures up to 600K. We applied +/-100V DC bias and concluded that under the same DC bias conditions, a frequency tuning of ~3% is measured at 600K, which is about 3 times larger than at room temperature. The FBARs demonstrate two operating states: metal-polar and N-polar and the electromechanical coupling coefficient ($k_{\mathbf {t}}^{\mathbf {2}}$) can be tuned with DC bias. This unique behavior paves a path forward for $k_{\mathbf {t}}^{\mathbf {2}}$ and frequency modulation in ferroelectric resonator elements. [2021-0214] [ABSTRACT FROM AUTHOR]

$\beta $ -phase gallium oxide ($\beta $ -Ga2O3) is drawing significant attention in the power electronics field due to its remarkable critical electric field strength [greater than gallium nitride (GaN) and silicon carbide (SiC)] and the availability of high-quality melt-grown substrates providing the opportunity for low-cost manufacturing. However, because of the low thermal conductivity of $\beta $ -Ga2O3, thermal management strategies at the device-level are required to achieve the targeted high-power capabilities. In this work, the effects of the anisotropic thermal conductivity of $\beta $ -Ga2O3 and the geometrical design of the metal electrodes/interconnects on the device self-heating were investigated. For a power density (${P}_{\text {dis}}$) of 1 W/mm at ${V}_{\text {GS}} =$ 4 V (i.e., a fully open channel condition), when the channel width is along a direction perpendicular to ($\bar {{2}}{01}$), the channel temperature decreases by 10% as compared to a case aligning the channel length along the direction close to [100]. Also, by decreasing the width of the interconnect between the drain electrode and the metal bond pad (serving as a heat pathway) from 100 to $10~\mu \text{m}$ (90% reduction), the channel temperature increased by ~8% for ${P}_{\text {dis}} =$ 1 W/mm. Last, for devices with identical heat generation profiles, increasing the distance between the gate and drain contact from 1 to 10 $\mu \text{m}$ , results in a 35% increase in the channel temperature rise. This work highlights the importance of thermally aware device layout design for lateral $\beta $ -Ga2O3 transistors, in terms of maximizing both the electrical and thermal performance. [ABSTRACT FROM AUTHOR]

Vegetable oils are subjected to heat treatments during processing and changes during storage. Thus, it is required, for usage as a food source, the evaluation of their thermo-oxidative stability and physicochemical characteristics. In this context, the objective of this paper was to evaluate the oil of catole coconut (Syagrus cearensis), aiming to characterize its identity and quality, as well as its antioxidant capacity and thermo-oxidative stability. The catole coconut was collected in the city of Lagoa Seca-PB, Brazil, its almonds were dried in a stove and the catole oil was obtained by cold pressing. The results of the physicochemical parameters complied with the current legislation, with average values ​​of 2.48 mg KOH g−1 oil for acid value, 0.14 meq peroxide kg−1 oil for peroxide value and 253 mg KOH g−1 oil for saponification value. Catole oil presented the profile of saturated fatty acids (84.42%), with the predominance of lauric acid (45.06%), besides major phenolic compounds such as salicylic acid [12.324 mg (100 g−1) of oil] and myricetin [1.405 mg (100 g−1) of oil]. The thermogravimetric profile remained stable to decomposition at temperatures up to around 240 °C and oxidative stability withstood at 110 °C for more than 48 h. Therefore, it was possible to identify and characterize this unexplored oilseed species of the Brazilian semiarid, diversifying its use in the food industry. [ABSTRACT FROM AUTHOR]

Banana-crop represents an essential segment in Brazil's socio-economic structure. However, the residues of banana-crop discarded cause problems of contamination in the crop and environment. Waste reuse technologies for the production of new chemical compounds with high conditioning and nutritional potential of soils are emerging as an efficient and economically viable way in terms of production and market value. From this perspective, the banana-crop residues torrefied, containing incorporated fertilizers, appears as an alternative to the reuse of that biomass in the generation of a slow-release biofertilizer. Biochar was produced from banana-crop pseudostem by torrefaction at 240 °C (BF sample). Urea (N), KCl (K), and diammonium phosphate (P) were added to BF, then pelletized to produce the BF-N, BF-K, and BF-P fertilizers. The relative water sorption kinetics by time was evaluated using an exponential method, with a maximum of 10.5% (w/w) sorption for the BF-N sample and a maximum adsorption time (95%) of 22.25h. The swelling of BF in water was evaluated by TMA, with a maximum ε = 22.4%. TG and DTG curves were used to obtain the proximate analysis, the thermal stability of the samples, and the urea content overtime of the BF-N sample in an aqueous medium and soil. FTIR spectra allowed to evaluate the interactions of N, P, and K with BF during the production of BF-N, BF-P, and BF-K. Two models, exponential (EM) and quotient (QM), were proposed and assessed for release kinetic parameters of N, P, and K from BF, BF-N, BF-P, and BF-K fertilizers in water and two kinds of soils under controlled conditions. The kinetics parameters allowed a discussion on the mechanisms of nutrient release in both water and soil, and the adjustment of the kinetic release model showed the potential for application as slow-release fertilizers. [ABSTRACT FROM AUTHOR]

Type-1 diabetes is one of the most prevalent metabolic disorders worldwide. It results in a significant lack of insulin production by the pancreas and the ensuing hyperglycemia, which needs to be regulated through a tailored administration of insulin throughout the day. Recent studies have shown great advancements in developing an implantable artificial pancreas. However, some improvements are still required, including the optimal biomaterials and technologies to produce the implantable insulin reservoir. Here, we discuss the employment of two types of cyclic olefin copolymers (Topas 5013L-10 and Topas 8007S-04) for an insulin reservoir fabrication. After a preliminary thermomechanical analysis, Topas 8007S-04 was selected as the best material to fabricate a 3D-printed insulin reservoir due to its higher strength and lower glass transition temperature (Tg). Fiber deposition modeling was used to manufacture a reservoir-like structure, which was employed to assess the ability of the material to prevent insulin aggregation. Although the surface texture presents a localized roughness, the ultraviolet analysis did not detect any significant insulin aggregation over a timeframe of 14 days. These interesting results make Topas 8007S-04 cyclic olefin copolymer a potential candidate biomaterial for fabricating structural components in an implantable artificial pancreas.

Two important biophysical properties, the thermal and UV-Vis screening capacity, of isolated tomato fruit cuticle membranes (CM) have been studied by differential scanning calorimetry (DSC) and UV-Vis spectrometry, respectively. A first order melting, corresponding to waxes, and a second order glass transition (Tg) thermal events have been observed. The glass transition was less defined and displaced toward higher temperatures along the fruit ripening. In immature and mature green fruits, the CM was always in the viscous and more fluid state but, in ripe fruits, daily and seasonal temperature fluctuations may cause the transition between the glassy and viscous states altering the mass transfer between the epidermal plant cells and the environment. CM dewaxing reduced the Tg value, as derived from the role of waxes as fillers. Tg reduction was more intense after polysaccharide removal due to their highly interwoven distribution within the cutin matrix that restricts the chain mobility. Such effect was amplified by the presence of phenolic compounds in ripe cuticle membranes. The structural rigidity induced by phenolics in tomato CMs was directly reflected in their mechanical elastic modulus. The heat capacity (Cprev) of cuticle membranes was found to depend on the developmental stage of the fruits and was higher in immature and green stages. The average Cprev value was above the one of air, which confers heat regulation capacity to CM. Cuticle membranes screened the UV-B light by 99% irrespectively the developmental stage of the fruit. As intra and epicuticular waxes contributed very little to the UV screening, this protection capacity is attributed to the absorption by cinnamic acid derivatives. However, the blocking capacity toward UV-A is mainly due to the CM thickness increment during growth and to the absorption by flavone chalconaringenin accumulated during ripening. The build-up of phenolic compounds was found to be an efficient mechanism to regulate both the thermal and UV screening properties of cuticle membranes.

Two important biophysical properties, the thermal and UV-Vis screening capacity, of isolated tomato fruit cuticle membranes (CM) have been studied by differential scanning calorimetry (DSC) and UV-Vis spectrometry, respectively. A first order melting, corresponding to waxes, and a second order glass transition (T g ) thermal events have been observed. The glass transition was less defined and displaced toward higher temperatures along the fruit ripening. In immature and mature green fruits, the CM was always in the viscous and more fluid state but, in ripe fruits, daily and seasonal temperature fluctuations may cause the transition between the glassy and viscous states altering the mass transfer between the epidermal plant cells and the environment. CM dewaxing reduced the T g value, as derived from the role of waxes as fillers. T g reduction was more intense after polysaccharide removal due to their highly interwoven distribution within the cutin matrix that restricts the chain mobility. Such effect was amplified by the presence of phenolic compounds in ripe cuticle membranes. The structural rigidity induced by phenolics in tomato CMs was directly reflected in their mechanical elastic modulus. The heat capacity (Cp rev ) of cuticle membranes was found to depend on the developmental stage of the fruits and was higher in immature and green stages. The average Cp rev value was above the one of air, which confers heat regulation capacity to CM. Cuticle membranes screened the UV-B light by 99% irrespectively the developmental stage of the fruit. As intra and epicuticular waxes contributed very little to the UV screening, this protection capacity is attributed to the absorption by cinnamic acid derivatives. However, the blocking capacity toward UV-A is mainly due to the CM thickness increment during growth and to the absorption by flavone chalconaringenin accumulated during ripening. The build-up of phenolic compounds was found to be an efficient mechanism to regulate both the thermal and UV screening properties of cuticle membranes. [ABSTRACT FROM AUTHOR]

This paper reports on the processing and overall characterization of walnut shell powder (WSP) filled polyester composite. The effects of this filler on the properties of polyester resin are studied by conducting various characterization tests under controlled laboratory conditions. The composite formation mechanism has been explained by the interpretation of Fourier transform infrared (FTIR) spectroscopic and X-ray Diffraction (XRD) analysis. The study reveals that the incorporation of WSP particles modifies the density and porosity of the composites along with their tensile, compressive, flexural, and impact strengths. Thermo-gravimetric analysis (TGA) is done on the samples to get an insight into their thermal stability. Measurement of thermal conductivity is carried out on samples of different compositions, and it is found that the inclusion of walnut shell powder leads to significant improvement in the thermal insulation capability of polyester resin. It is recorded that with an increase in the WSP content from 0 to 20 wt. % in polyester, the value of the effective thermal conductivity (K eff ) drops by about 42%. It is further seen that with the incorporation of WSP, the coefficient of thermal expansion (CTE) of polyester is substantially lowered. [ABSTRACT FROM AUTHOR]

A new method for estimating the thermal properties of composite materials is proposed. It uses a previously developed thermal characterization method that is based on Karhunen–Loève decomposition (KLD) techniques in association with infrared thermography experiments or any other kind of experimental device providing dense data in spatial coordinates. The novelty of this work lies in the introduction of two techniques based on two phase-wise defined test functions that extend the previously developed method to cases where the morphology of the composite material is not straightforward. Thanks to the orthogonal properties of KLD, only a few eigenelements are needed for an accurate estimation, which allows for a significant amplification of the signal/noise ratios. Furthermore, the proposed methods represent an attractive combination of parsimony and robustness to noise thanks to spatially uncorrelated noise being entirely reported on states. The effectiveness and accuracy of both techniques are proven with numerical tests. [ABSTRACT FROM AUTHOR]

The production of polyhydroxyalkanoates (PHAs) from waste cooking oil (WCO) by a mixed culture was investigated in the present study at increasing WCO concentrations, temperature and ammonium availability. The PHA production was done in two steps: in the first step, a mixed culture was enriched in PHA-accumulating bacteria from activated sludge in a sequencing batch reactor operated in a feast-famine mode and in the second step the PHA accumulation by the enriched mixed culture was assessed in a batch reactor. In the enrichment step, two substrates, WCO and nonanoic acid were used for enrichment and in the PHA accumulation step only WCO was used. It was not possible to enrich a mixed culture in PHA-accumulating bacteria using WCO as substrate due to the development of filamentous bacteria causing foam formation and bulking in the reactor. However, our results showed that the mixed culture continuously fed with nonanoic acid was enriched in PHA-accumulating bacteria. This enriched culture accumulated both scl- and mcl-PHA using WCO as substrate. The maximum PHA accumulation capacity of this mixed culture from WCO was 38.2% cdw. Increasing the temperature (30–40 ℃) or WCO concentrations (5–20 g/l) increased the PHA accumulation capacity of the mixed culture and the ratios of scl-PHA to mcl-PHA. The presence of ammonium increased PHA accumulation (21.9% cdw) compared to the complete absence of ammonium (5.8% cdw). The thermal characterization of the PHA exhibited the advantageous properties of both scl- and mcl-PHA, i.e., higher melting temperature (152–172 ℃) similar to scl-PHA and a lower degree of crystallinity (12%) similar to mcl-PHA. This is the first study to report the potential of open mixed culture to produce scl- and mcl-PHA from WCO and thus contributing to the understanding of sustainable polymer production. • The mixed culture enriched in nonanoic acid accumulated scl- and mcl-PHA from WCO. • Maximum PHA accumulated by the mixed culture was 38.2% cdw from 10 g/L WCO at 40 ℃. • The presence of ammonium increased the PHA accumulation capacity. • The scl- to mcl-PHA ratio was affected by temperature and WCO concentration. • Enrichment of a mixed culture with WCO promoted the growth of filamentous organisms. [ABSTRACT FROM AUTHOR]

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The paper aims to compare different methods able to estimate the specific loss power (SLP) generated by three different types of magnetic nanoparticles, MNPs, dispersed in a suspension fluid, e.g., octane or water. The nanoparticles were characterized morphologically in terms of shape and size, chemically for composition and their physical properties like magnetization and SLP were studied. We evidenced the differences in SLP evaluation due to the applied method, particularly in the presence of thermally induced phenomena such as aggregation or precipitation of MNPs that can affect the heating curve of the samples. Then, the SLP determination methods less sensible to this phenomenon appear to be the ones that use the initial slope when the sample is in quasi-adiabatic condition. Finally, we propose a comparison of those methods based on the pros and cons of their use for the SLP determination of magnetic nanofluids. In particular, the analysis of the behavior of the heating curve is useful to evaluate the useful amplitude of the interval analysis for the initial slope methods.

In this study, it was aimed to investigate the effect of zinc borate additive of thermal properties on nanofiber textile surfaces produced by doping different amounts of zinc borate into polyacrylonitrile-co-vinyl acetate (P(AN-VAc)). For this purpose, nanofiber textile surfaces were produced from the zinc borate doped and undoped P(AN-VAc) solutions prepared with a 10% concentration in dimethylformamide by electrospinning method. Some analyzes and tests were carried out to determine the structural, morphological, physical, mechanical and thermal properties of the zinc borate doped and undoped nanofiber textile surfaces produced. The presence of zinc borate was detected on zinc borate doped nanofiber surfaces produced as a result of Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray spectroscopy (EDX) analyses. The morphological properties of the produced surfaces were investigated by scanning electron microscopy (SEM) and it was observed that uniform nanofiber structure was formed in all samples. As a result of tensile strength tests, it was determined that the zinc borate additive reduces values of tensile strength and elongation of nanofiber surfaces. The thermal properties of all the produced nanofiber textile surfaces were examined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), limit oxygen index (LOI) and vertical flammability tests. As a result of the thermal analyses and tests, it was determined that the zinc borate additives improve the thermal properties of the P(AN-VAc) nanofiber textile surfaces and the thermal resistances of them increases with the increase of the zinc borate additive. [ABSTRACT FROM AUTHOR]

The manufacturing technology of historical mortars from the Roman to Medieval period apparently has not undergone evolutions. As reported in the literature, a quality decrease in the raw material occurred after the fall of the Roman Empire. During the Roman Age, the mortars presented the requirements of long durability due to hydraulic characteristics, and in later times, the production has only partially maintained the ancient requirements. To focus on the different production technologies between Roman and Medieval mortar, this research presents the case study of San Saturnino Basilica (Italy), where an archaeological mortar stratigraphy from Roman to Middle Ages is well preserved. An archaeometric characterization was performed to compare the mortars of the Roman period with the mortars of the Medieval period collected from the case-study monument. This comparison was carried out by measuring some physical-mechanical, mineralogical, petrographic and thermal features that give more information about the durability and resistance to mechanical solicitations and weathering. After the characterizations, contrary to what is reported in the bibliography, a better quality of Medieval materials than Roman ones is pointed out. This has been highlighted by higher hydraulicity, mechanical performance, and a more appropriated particle-size distribution of aggregates. [ABSTRACT FROM AUTHOR]

This study presents indoor and field validation results for two versions of the "DUSST" optical soiling sensor, intended to be a low‐cost and low‐maintenance device for measuring photovoltaic soiling losses. Indoor testing covers irradiance calibration and temperature dependencies, which are necessary to achieve high accuracy, low uncertainty field measurements. Field testing includes an array of different environments including Saudi Arabia, California, Utah, and Colorado. DUSST versions include a configuration with a 530‐nm light emitting diode (LED) (discussed in previous work) and a unit with seven white LEDs and a polycarbonate collimating optic. The new design increases light intensity fivefold and demonstrates a single linear calibration coefficient is effective to measure soiling losses as high as 75%. Field data from Utah and California demonstrate that daily soiling loss measurements and soiling rate calculations closely match both reference cell and full‐size module measurements of soiling losses and soiling rates. Corrective methods employed on the Utah DUSST sensor suggest that it is possible to achieve measurement errors as low as ±0.1% at two standard deviations. Field data from both Colorado and Saudi Arabia demonstrate that LED lens soiling can occur and that further design optimizations are needed. The lesson learned from all the field deployment locations suggests directions for future design improvements. [ABSTRACT FROM AUTHOR]

The development of reusable launch vehicles (RLV) must include a significant reduction of the payload transportation costs. One of the most expensive components of a RLV is the thermal protection system (TPS), which preserves the spacecraft from the high thermal loads during re-entry. Reusability and on-orbit environment are key parameters in TPS design, mainly as far as the adopted materials are concerned. Aim of the work is to analyze a novel TPS concept, proposing an hybrid multiscale ceramic coating - i.e., alumina-based varnish enriched by silica nanoparticles - to be applied on Carbon/Carbon (C/C) plates. The treatment is aimed at preserving the thermo-mechanical properties of the ceramic substrate from the detrimental space environment conditions, such as LEO thermal cycles, outgassing due to ultra-high vacuum, as well as Atomic Oxygen/UV irradiation. Experimental measurements of the coefficient of thermal expansion (CTE) are performed in order to evaluate the thermal stress and performance of both substrate and coating layer. Particular emphasis is devoted to evaluate the effect of coating/substrate adhesion, which may result in anomalous mechanical behavior. By the use of a robust numerical technique, known as the inverse method, heat capacity and thermal conductivity are analyzed; such approach is particularly suited to address these kind of problems, as a number of physical parameters concur for a reliable determination of material properties. The special test equipment and the regularizing algorithm for solving the heat conduction problem are described. After thermal conditioning, the integrity of coating and substrate is investigated by full morphological analysis using SEM/EDX techniques. • Hybrid multiscale ceramic coating of C/C structures design and manufacturing for re-entry vehicles is presented. • Thermal expansion and heat transport properties of basic and nanostructured coated material are analyzed. • SiO 2 nano-inclusion within Al 2 O 3 -based refractory varnish improves the coating resistance to thermal stress. [ABSTRACT FROM AUTHOR]

In recent years, continuous growing interests have been seen in bringing artificial intelligence capabilities to mobile devices. However, the related work still faces several issues, such as constrained computation and memory resources, power drain, and thermal limitation. To develop deep learning (DL) algorithms on mobile devices, we need to understand their behaviors. In this article, we explore the architectural behaviors of some mainstream DL frameworks on mobile devices by performing a comprehensive characterization of performance, accuracy, energy efficiency, and thermal behaviors. We experimentally choose four model compression methods to perform on networks and in addition, analyze the related impact on the nodes amount, memory, execution time, model size, inference time, energy consumption, and thermal distribution. With insights into DL-based mobile application characteristics, we hope to guide the design of future smartphone platforms for lower energy consumption. [ABSTRACT FROM AUTHOR]

In this study, it was aimed to investigate the effect of boric acid additive of thermal properties on nanofiber textile surfaces produced by doping different amounts of boric acid into polyacrylonitrile-co-vinyl acetate (P(AN-VAc)). For this purpose, nanofiber textile surfaces were produced from the boric acid doped and undoped P(AN-VAc) solutions prepared with a 10 % concentration in dimethylformamide by electrospinning method. Some analyzes and tests were carried out to determine the structural, morphological, physical, mechanical and thermal properties of the boric acid doped and undoped nanofiber textile surfaces produced. The presence of boric acid was detected on boric acid doped nanofiber surfaces produced as a result of Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray spectroscopy (EDX) analyses. The morphological properties of the produced surfaces were investigated by scanning electron microscopy (SEM) and it was observed that uniform nanofiber structure was formed in all samples. As a result of tensile strength tests, it was determined that the boric acid additive reduces values of tensile strength and elongation of nanofiber surfaces. The thermal properties of all the produced nanofiber textile surfaces were examined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and vertical flammability tests. As a result of the thermal analyses and tests, it was determined that the boric acid additives improve the thermal properties of the P(AN-VAc) nanofiber textile surfaces and the thermal resistances of them increases with the increase of the boric acid additive. [ABSTRACT FROM AUTHOR]

In this research paper, the determination of thermal expansivity and thermal conductivity has been accomplished for Al 6061, Silicon Carbide and Graphite hybrid metal matrix composites from room temperature to 3 0 0 ∘ C. Aluminium-based composites reinforced with Silicon Carbide and Graphite particles have been prepared by stir casting technique. The thermal expansion and thermal conductivity properties of hybrid composites with different percentage compositions of reinforcements have been investigated. The results have indicated that the thermal expansivity and thermal conductivity of the different compositions of hybrid MMCs decrease by the addition of Graphite with Silicon Carbide and Al 6061. Few empirical models have been validated for the evaluation of thermal expansivity and thermal conductivity of hybrid composites. Using the experimental values, namely modulus of elasticity, Poisson ratio and thermal expansivity, computational investigation has been carried out to evaluate the thermal parameters, namely thermal displacement, thermal strain and thermal stress. Similarly, using the experimental values, namely density, thermal conductivity, specific heat capacity and enthalpy at varying temperature ranges, computational investigation has been carried out to evaluate thermal gradient and thermal flux. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the changes in the characteristics of Eucalyptus spp. from Paraíba Valley region, Sao Paulo - Brazil after torrification process. Torrification is a thermochemical process that occurs at temperatures lower than the pyrolysis process as a pretreatment to improve biomass characteristics for use as biofuel energy in power generation. An experimental study was carried out in a batch reactor at three temperatures (240 °C, 260 °C and 280 °C) with residence time of 30 and 60 minutes. At the indicated operating conditions by elemental analysis, higher heating value and thermogravimetric analysis were evaluated. Result showed that there was a reduction in the oxygen/carbon (O/C) and hydrogen/carbon (H/C) ratios, causing an increase in the thermal energy quality of torrified wood, about of 28 % and 47 % at temperatures of 260 °C with residence time of 60 minutes and 280 °C with 30 minutes, respectively. A thermogravimetric analysis showed that at 260 °C the hemicellulose was almost completely degraded leaving the fuel in better conditions for combustion or gasification processes.

Building performance is strongly influenced by the performance of their structural parts, consequently affecting annual energy demands. The thermal characterization of building components can be achieved thanks to the knowledge of their internal layers and the thermal properties of each material. Considering existing buildings, technical data may be unidentified and heat transfer phenomena between walls and environments can be influenced by air-conditioning systems and local thermo-fluid dynamic conditions. Moreover, the conversion of an existing building into a Nearly Zero Energy Building (NZEB) requires accurate measurements and simulations compared with Standards suggestions, based on simplified procedures. Therefore, on-site surveys become fundamental. Standards suggestions can help engineers or technicians to define some unknown information related to heat transfer coefficients and thermo-physical properties. Nevertheless, can Standards' suggestions be considered reliable in every situation? This paper tries to answer this question, debating some investigations conducted in the last years and proposing a methodological approach.

This study focuses on the preparation of a novel composite phase change material (PCM) for an application of Latent Heat Thermal Energy Storage in buildings. The aim of this application is to improve thermal inertia in buildings. A good thermal inertia, involves the improvement of thermal comfort and energy saving. The experimented materials’ components are selected for their availability, safety and low cost. Paraffin with a melting temperature range close to 30°C is selected as a PCM; it is composed of microcrystalline wax and liquid paraffin. The matrix is prepared from plaster, graphite powder and cellulose fibers. The PCM is introduced in the matrix following the immersion method. Several samples are prepared; there after they are subjected to a thermal treatment at 50°C for 30 min on a filter paper. The purpose is to identify the performance of each sample to retain the PCM without leakages. Thermal and physicochemical characterizations are performed to study the composites’ properties: Scanning Electron Microscopy (SEM) is used to observe its microstructure; X-Ray Diffraction (XRD) identifies the crystallographic structure of the composite-PCM while Fourier Transformed Infrared Spectroscopy (FT-IR) reveals the chemical compatibility between its different components. Thermo Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) are performed for thermal characterization. The thermal performance of the composite-PCM is verified experimentally using thermocouple measurements connected to a temperature recorder apparatus. The measurements are done simultaneously on two pellets; the first contains PCM while the second does not contain PCM.

Rocket fuels are subjected to intense in-flight inertial, pressure and thermal loads that has drastic effect on its performance. In order to achieve optimal results, we require functionally-graded solid propellant (FGSPs), specifically designed for each flight condition. A novel series of FGSPs were developed using Paraffin Wax (as fuel) and Hydroxyl-terminated polybutadiene (as binder); treated with Dioctyl adipate (C 22 H 42 O 4), Toluene diisocyante (C 9 H 6 N 2 O 2) and Glycerol (C 3 H 8 O 3). These FGSPs were further doped with light metal hydride nano-powders including Lithium aluminium hydride (LiAlH 4) and Magnesium hydride (MgH 2). The FGSPs were investigated for thermo-physical and ballistic performance using several characterisation techniques. The Magnesium hydride-doped FGSPs exhibited lower viscosity that fostered entrainment-aided combustion. FGSPs doped with Lithium aluminium hydride featured solid-like behaviour that makes them more stable in solid phase and less susceptible to in-flight loads. Thermal characterisation revealed that Lithium aluminium hydride makes FGSPs comparatively more resistant towards pyrolysis thereby producing greater char-yield. Eventually, combustion characteristics were evaluated by performing static ballistic firings of the developed FGSPs. The doped FGSPs exhibited significant enhancement in regression compared to the base fuel and conventional HTPB fuel. The MgH 2 -doped FGSP exhibited maximum enhancements of up to 224% and 353% as compared with the base fuel and HTPB, respectively. Regression rates of the test-fired FGSPs (as a function of oxidiser mass flux). Image 1 • Novel series of functionally-graded solid propellant are proposed using Paraffin Wax and Hydroxyl-terminated polybutadiene. • They are doped with light metal hydride nano-powders. • Improved thermo-physical and ballistic performance are obtained. • Combustion characteristics were evaluated by performing static ballistic firings. [ABSTRACT FROM AUTHOR]

• The design and the features of the soiling optical detector DUSST are presented. • The thermal characterization of the components of the detector is performed. • A factor of 0.052 mA/°C can correct the effect of the LED temperature. • A validation of the performance of DUSST is made using masks and natural soiling. • DUSST can estimate the transmittance losses with high accuracy (R2 > 0.94). Nowadays, photovoltaic (PV) technology has reached a high level of maturity in terms of module efficiency and cost competitiveness in comparison with other energy technologies. As PV has achieved high levels of deployment, the development of devices that can help to reduce PV operation and maintenance costs has become a priority. Soiling can be cause of significant losses in certain PV plants and its detection has become essential to ensure a correct mitigation. For this reason, accurate and low-cost monitoring devices are needed. While soiling stations have been traditionally employed to measure the impact of soiling, their high cost and maintenance have led to the development of innovative low-cost optical sensors, such as the device presented in this work and named "DUSST" (Detector Unit for Soiling Spectral Transmittance). The thermal characterization of DUSST's components and the methodology used to predict soiling transmittance losses are presented in this study. The results show that the losses can be predicted with an error lower than 1.4%. The method has been verified with an experimental campaign with naturally soiled coupons exposed outdoors in Jaén, Spain. [ABSTRACT FROM AUTHOR]

Each of the elements that make up the turbocharger has been gradually improved. In order to ensure that the system does not experience any mechanical failures or loss of efficiency, it is important to study which engine-operating conditions could produce the highest failing rate. Common failing conditions in turbochargers are mostly achieved due to oil contamination and high temperatures in the bearing system. Thermal management becomes increasingly important for the required engine performance. Therefore, it has become necessary to have accurate temperature and heat transfer models. Most thermal design and analysis codes need data for validation; often the data available fall outside the range of conditions the engine experiences in reality leading to the need to interpolate and extrapolate disproportionately. This article presents a fast three-dimensional heat transfer model for computing internal temperatures in the central housing for non-water cooled turbochargers and its direct validation with experimental data at different engine-operating conditions of speed and load. The presented model allows a detailed study of the temperature rise of the central housing, lubrication channels, and maximum level of temperature at different points of the bearing system of an automotive turbocharger. It will let to evaluate thermal damage done to the system itself and influences on the working fluid temperatures, which leads to oil coke formation that can affect the performance of the engine. Thermal heat transfer properties obtained from this model can be used to feed and improve a radial lumped model of heat transfer that predicts only local internal temperatures. Model validation is illustrated, and finally, the main results are discussed. [ABSTRACT FROM AUTHOR]

In compliance with oncoming emission directives, turbocharging and increasing complexity in the turbocharger system demands a great effort from researchers on the development of effective procedures and tools to cope with the new technological exigencies. This article describes a methodology for studying oil-coking influence in turbocharger performance. A preliminary evaluation and calibration is done. The aim of this work focuses on the development of methodologies and tools that help to evaluate and understand the consequences that degraded oils can generate in the bearing system during enhanced oil-coking procedure. Several experimental tests have been carried out in an engine test bench and using an independent lubrication system that only feeds the turbocharger. The test campaign is done under a specific engine cycle and using oil artificially contaminated at two different levels. The work is divided into two parts. The first part provides a description and definition of test conditions for measuring of the maximum temperature in the bearing system and the second part tackles the measurement and post-processing of the main instantaneous parameters defining the engine and turbocharger behavior. [ABSTRACT FROM AUTHOR]

In the current research, magnesium oxide nanopowder (n-MgO) was prepared using dry chemistry method. The structural characterization of the prepared n-MgO was carried out using x-ray diffraction (XRD) technique and scanning electron microscope (SEM). The powder was mixed with epoxy resin at ratios of 2%, 4%, 6% and 8%. The effect of reinforcement of n-MgO on thermal properties of epoxy-resin-based composites such as thermal rate and insulation index was studied at three different temperatures: 380, 680 and > 1800 K. Thermal testing that was carried out included thermal conductivity measurement using Mathis TCi and erosion rate test using oxy-acetylene flame technique. The results showed that increasing the content of n-MgO can significantly enhance the thermal properties such thermal conductivity, thermal diffusion, specific heat capacity as well as thermal resistance. [ABSTRACT FROM AUTHOR]

High-performance polymers are plastics that have better thermal and mechanical properties than other engineering plastics. In general, polymers are relatively light materials when compared to metals. Currently, research era is focused on developing high-performance plastic such as PEEK (polyetheretherketone) for applications in drones, aircrafts, rockets and formula 1. This is due to its durability comparable to metal parts, its significant lightness and its capacity able to withstand operating temperatures of above 150 °C. However, these materials are well established and fabricated using conventional production method, which limits the freedom to achieve high-complexity structures. 3D printing or additive manufacturing techniques allow for complex shapes to be easily produced together with a degree of control over the process parameters. Though fused deposition modelling was attempted earlier with these polymers, more promising approaches such as robot-based extrusion method attained very little attention. In particular, 3D printing mould structures using high-performance materials for automated fibre placement (AFP) process need sufficient attention. This paper attempts experimental investigations with PEEK, using the robotic extrusion method. Thus, the thermal, mechanism of material consolidation, the effects of significant process parameters on critical responses and thermomechanical properties are determined with respect to its application for moulds for AFP process. [ABSTRACT FROM AUTHOR]

Thanks to the System-on-Package technology (SoP) the integration of different elements into a single package was enabled. However, from the thermal point of view the heat removal path in modern packaging technologies (FCBGA) goes through several layers of thermal interface material (TIM) that together with the package material create a relatively high thermal resistance which may lead to elevated chip temperature which causes functional error or other malfunctions. In our concept, we overcome this problem by creating integrated microfluidic channel based heat sink structures that can be used for cooling the high heat dissipation semiconductor devices (e.g.: processors, high power transistor or concentrated solar cells). These microchannel cooling assemblies can be integrated into the backside of the substrate of the semiconductor devices or into the system assemblies in SoP technology. In addition to the realization of the novel CMOS compatible microscale cooling device we have developed precise and valid measurement methodology, simulation cases studies and a unique compact model that can be added to numerical simulators as an external node. In this paper the achievements of a larger research are summarized as it required the cooperation of several experts in their fields to fulfil the goal of creating a state-of-the-art demonstrator. [ABSTRACT FROM AUTHOR]