Lower Mass Loss Research Articles

Don\u2019t drink it, bury it: comparing decomposition rates with the tea bag index is possible without prior leaching

PurposeThe standardized ‘Tea Bag Index’ enables comparisons of litter decomposition rates, a key component of carbon cycling, across ecosystems. However, tea ‘litter’ may leach more than other plant litter, skewing comparisons of decomposition rates between sites with differing moisture conditions. Therefore, some researchers leach tea bags before field incubation. This decreases comparability between studies, and it is unclear if this modification is necessary.MethodsWe submerged green and rooibos tea bags in water, and measured their leaching losses over time (2 min – 72 h). We also compared leaching of tea to leaf and root litter from other plant species, and finally, compared mass loss of pre-leached and standard tea bags in a fully factorial incubation experiment differing in soil moisture (wet and dry) and soil types (sand and peat).ResultsBoth green and rooibos tea leached strongly, levelling-off at about 40% and 20% mass loss, respectively. Mass loss from leaching was highest in green tea followed by leaves of other plants, then rooibos tea, and finally roots of other plants. When incubated for 4 weeks, both teas showed lower mass loss when they had been pre-leached compared to standard tea bags. However, these differences between standard and pre-leached tea bags were similar in moist vs. dry soils, both in peat and in sand.ConclusionsThus, despite large leaching losses, we conclude that leaching tea bags before field or lab incubation is not necessary to compare decomposition rates between systems, ranging from as much as 5% to 25% soil moisture.

EFFECT OF THE LENGTH OF THE FLOWERING-HARVEST INTERVAL ON THE RIPENING AND QUALITY OF THE 'KENT' MANGO IN CÔTE D'IVOIRE

The physiological stage of mango maturity at harvest affects fruit quality at the time it is commercialized. The objective assessment of the mango maturity stage at harvest remains a challenge because of the multiple interactions between the visual aspect, the physicochemical composition, and the morphology of the fruit. This study aims to quantify the optimal harvest date to guarantee the maturity and quality of mango cv. ‘Kent’. In this study, which took place in Korhogo in northern Côte d’Ivoire, the maturity stage and the quality of fruits were measured on 240 Kent mangoes harvested at four different harvest dates (90, 95, 100, and 105 days after flowering). A morphological, physical, and chemical characterization (length, width, mass, soluble sugar content, dry matter, skin appearance, and mass loss) was carried out at each date on 30 fruits at harvest and 30 fruits after ripening at room temperature. The number of days necessary for ripening was quantified. The results showed that the optimal harvest date is 100 days after flowering for Kent mangoes in Côte d’Ivoire. Mangoes harvested at this date developed better organoleptic characteristics (less wrinkled skin, lower mass losses, and a shorter ripening time). Assessment of the harvest date, guaranteeing better ripening of the fruit, is of utmost importance for organizing harvests in the mango sectors in West Africa, and especially in Côte d’Ivoire.

Evaluating the durability, microstructure and mechanical properties of a clayey-sandy soil stabilized with copper slag-based geopolymer against wetting-drying cycles

This study was conducted on durability of the clayey-sand stabilized using the copper slag (CS)-based geopolymer against wetting-drying (W-D) cycles. In this investigation, the mix of 0, 10, and 15% CS and alkaline activator liquid was used. In this solution, the ratio of NaOH to Na2SiO3 is 70:30 and the weight ratio of CS to solution is 1:1. To evaluate the effects of CS content and NaOH concentration (8 M and 11 M) on the strength, durability, and microstructural variation, a series of experiments were conducted after different cycles. The tests carried out for this purpose include standard proctor compaction test, unconfined compressive strength (UCS), Atterberg limits, accumulative loss of mass, swell and shrinkage, ultrasonic P-wave velocity, pH, toxicity characteristic leaching procedure (TCLP), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) tests. The UCS results demonstrated a remarkable reduction in cycle 2 due to W-D cycles, followed by a decrease in further cycles. As a result of Atterberg limits, lower PI leads to the lower potential to swell or shrinkage; thus, the lower loss of soil mass with a higher amount of CS content is obtained. The microstructure analysis showed that with the increase in cycle number, the abundance of microcracks and voids were increased. Moreover, dissolved geopolymerization products leached due to wet cycles and formed gel becomes weaker. The results showed that all the chosen mixtures were durable and endured all 12 W-D cycles. Furthermore, their mass loss was lower than allowable mass loss content of ASTM D559, suggesting that this stabilization method was appropriate for this soil.

Influence of Aging on the Failing Behavior of Automotive Lithium-Ion Batteries

Lithium-ion batteries (LIBs) are a dominant state-of-the-art energy storage system and have importance in the automotive sector. Still, LIBs suffer from aging effects and serious hazards from failing batteries are possible. These failures can lead to exothermic chemical reactions inside the cell, ending up in thermal runaway (TR). TR has caused most electric vehicle (EV) fires. Since statistically most accidents with EVs happen after about one year of vehicle usage, in particular, the failing behavior of aged cells needs to be investigated. Little information is available in open literature about the influence of aging paths on the failing behavior and especially on the degassing behavior of large automotive LIBs. Therefore, this study investigates the influence of three different aging paths (cyclic at −10 °C and at 45 °C and calendric at 60 °C) on the thermal behavior, the vent gas emission, and the vent gas composition. The results show a clear effect of aging on the failing behavior. The aged cells showed a less violent failing reaction, reduced maximal temperatures, lower amount of produced gas, significantly lower amount of CO in the vent gas, and lower mass loss than fresh cells in the same overtemperature experiments. The results are valuable for the scientific and industrial community dealing with LIBs.

Influence of Shelf Life on Mechanical Properties of Glass Fibre Reinforced Composites

The present paper was focused on studying the influence of shelf life of an epoxy matrix on the mechanical properties of glass fibre reinforced composites. For the study, two types of the same epoxy system were used, one during its shelf life and one out of its shelf life. The reinforcement used consisted in E-glass fibre fabric. Mechanical investigations were realized in order to compare the materials in terms of loss of mechanical strength and elastic properties. Therefore, three mechanical tests were performed: tensile tests, in-plane shear and open-hole tensile tests. The results showed that the shelf life affects the mechanical properties of the polymeric composite. A decrease of 24% in tensile strength was recorded along with a 28% decrease of the in-plane shear strength and 55% of open-hole tensile strength for the composite manufactured with the out of shelf life epoxy system compared with the other composite. An overall reduction of mechanical strength and elastic properties of the composite material was observed, primarily due to polymeric matrix degradation, which after long periods it could be prone to brittleness and susceptible to delamination and fracture. The thermogravimetric analysis showed that thermal induced changes are happening at a higher speed in the out of shelf life composite, a lower mass loss being registered for new epoxy composite.

Effect of Torrefaction on Thermal and Kinetic Behavior of Kenaf during Its Pyrolysis and CO2 Gasification

Torrefaction is an appealing pretreatment method for improving the fuel properties of kenaf biomass before its utilization in thermochemical processes. This study evaluated and compared the impact of torrefaction on thermal behavior and kinetics during pyrolysis and gasification. Thermogravimetric analysis experiments were conducted at temperatures of 300–1173 K at several heating rates under N2 and CO2 atmospheres. The raw and torrefied kenaf (RK and TK) during CO2 gasification in the low-temperature region (<900 K) was found to exhibit a tendency that was similar to that of N2. However, TK during CO2 gasification resulted in a lower maximum mass loss rate, delayed initiating temperature, and lower devolatilization index due to lower reactivity. In addition, the gasification reaction of CO2 and char was observed to occur in the high-temperature region (> 900 K), thus improving conversion efficiencies. The activation energy for TK in a CO2 atmosphere depending on the conversion was calculated using the distributed activation energy method. The activation of RK during CO2 gasification was higher than that of N2. However, TK during CO2 gasification exhibited a lower activation energy compared to that of N2, indicating its potential as a better feedstock during the CO2 gasification process and the ability to save energy.

Mechanical behavior and wear characteristics of fine grained ZE41 magnesium alloy

AbstractZE41 magnesium alloy was successfully produced by friction stir processing and grain refinement was achieved from a starting size of 107 μm±6.7 μm to 3.5 μm±1.5 μm. MgZn intermetallic which was appeared as network like structure at the grain boundaries before friction stir processing was greatly affected due to the severe plastic deformation and broken as small particles as observed from the microstructural studies. Higher hardness (≈30 %) was measured for the fine grained ZE41 magnesium alloy compared with the base alloy due to the grain refinement. From the tensile tests, yield strength and ultimate tensile strength was significantly increased at the cost of decreased ductility reflected in lower strain for the fine grained ZE41 compared with the base alloy. Wear studies showed higher coefficient of friction and lower mass loss for the grain refined ZE41 magnesium alloy. From the results, it can be understood that the grain refinement achieved by friction stir processing has a profound influence on enhancing the mechanical and tribological properties of ZE41 magnesium alloy.

Novel Single-Phase Short-Stroke Tubular Permanent Magnet Oscillating Machines with Partitioned Stator

This paper presents three novel configurations of single-phase (SP) short-stroke (SS) tubular permanent magnet oscillating machines (TPMOMs) with partitioned stator (PS), termed PS-SPSS-TPMOMs. The machine structures are described and the influence of permanent magnet pole alignment with either stator slot or stator tooth is investigated. It is found that the PM poles should be aligned with the stator slots in order to ease the oscillation. The electromagnetic performance of these proposed machines is analyzed and compared. The results show that such machines have the advantages of low mover mass and low magnet eddy current loss, compared with a conventional surface-mounted SPSS-TPMOM.

Effects of microorganism-mediated inoculants on humification processes and phosphorus dynamics during the aerobic composting of swine manure

There is significant interest in the treatment of swine manure, which is a hazardous biowaste and a source of pathogenic contamination. This work investigated the effects of microorganism-mediated inoculants (MMIs) on nutrient flows related to humification or phosphorus (P) dynamics during the aerobic composting of swine manure. The impact of MMIs on microbe succession was also evaluated. The addition of MMIs had positive effects associated with nutrient flows, including thermal activation, decreases in certain fluorescence emissions, lower mass loss and variations in levels of certain elements and functional groups. MMIs altered the maturation behavior and kinetics of organic matter while improving microbial activity. Phosphorus was found in the compost in the forms of MgNH4PO4·6H2O crystals and Poly-P as the IP species, and Mono-P as the OP species in compost generated from the dissolution or inter-transformation among P pools. These nutrient flows are attributed to changes in the structure of microbial communities as a consequence of introducing MMIs. Diverse microbial compositions were identified in different composting phases, although Bacillus appeared in each phase. This work provides support for the aerobic composting of hazardous biowaste as well as an improved understanding of nutrient flows, as a means of producing higher quality compost.

SO2-generating pads reduce gray mold in clamshell-packaged ‘Rubi’ table grapes grown under a two-cropping per year system

The aim of this work was to evaluate different SO2-generating pads and liners to control gray mold in ventilated clamshell-packaged ‘Rubi’ table grapes grown under a two-cropping per year system. The treatments consisted of SO2-generating pads (slow release or dual release) and plastic liners with different perforations (microperforated; 2.0; 4.0 or 5.0 mm in diameter) and a control, only with the standard microperforated plastic liner. The packaged grapes were stored in a cold chamber at 1.0 ± 1.0 °C and 95% relative humidity. After 45 days, the grapes were removed from cold storage and placed, without liners and SO2-generating pads, for 3 days at room temperature (22.0 ± 1.0 °C). The evaluations occurred at 30 and 45 days after the beginning of cold storage, and the following variables were assessed: incidence of gray mold, mass loss, stem browning and shattered berries. At 3 days of shelf-life, the same variables were assessed, except mass loss. The completely randomized design was used as a statistical model with four replications, and each plot consisted of five bunches individually stored in ventilated clamshell-packaged. The dual release SO2-generating pads are efficient in controlling the gray mold in ‘Rubi’ table grapes regardless of the type of perforation of the plastic liners, with low mass loss and shattered berries, with good conservation of the freshness of the rachis. The disease was efficiently controlled in both annual crops. The slow-release SO2-generating pads, regardless of the type of perforation of the plastic liners, resulted in intermediate efficiency of gray mold control, with good physical quality of the bunches. Thus, the use of dual release SO2-generating pads is recommended to control gray mold in ventilated clamshell-packaged ‘Rubi’ table grapes.

Production and characterization of carbon/carbon composites from thermoplastic matrices

Carbon-carbon composites (C/C) are those that have carbonaceous matrix reinforced with carbon fiber. They are widely used in the aerospace field, due mainly to the properties such as low density, high stiffness, and excellent thermal resistance, in comparison to the ones with polymer or metallic matrix. They are obtained through composites of polymer matrix (thermoset or thermoplastic), from the heat treatment of carbonization. The objective of this work is to produce the C/C composite material from three different thermoplastic laminates (PEKK/CF, PEEK/CF and LMPAEK/CF) as well as to compare these materials with C/C composites obtained from thermoset matrices, to show their advantages and disadvantages in relation to them. Such comparison was substantiated with TGA, DSC, SEM and XRD analyzes. In this work, the TGA showed the proposed process presents a lower mass loss, resulting in a faster and cheaper process, comparing thermoplastic with thermoset laminates. The DSC tests provided the basis for establishing the different heating rates. Through the SEM images it was possible to analyze the carbonization process. Finally, analyzes of cyclic voltammetry were made; through a comparison with Platinum electrode, C/C electrodes proved to be suitable for this application. Also, electrodes obtained from PEEK/CF presented better electrochemical responses.

Non-destructive measurement of Scots pine heartwood stilbene content and decay resistance by means of UV-excited fluorescence spectroscopy

Decay resistance is an important property of heartwood timber. The decay resistance of Scots pine heartwood correlates with its stilbene content, but the determination of both requires laborious and destructive analyses. To aid in the determination of these important properties, we investigated the feasibility of an optical method based on the intensity of UV-excited fluorescence for the non-destructive measurement of heartwood stilbene content and decay resistance. Fluorescence measurements carried out on samples from 58 trees showed a high correlation (r = 0.79, p < 0.000) between fluorescence intensity and stilbene content. The intensities measured from green and dried samples were highly correlated. The correlation between the fluorescence intensity and mass loss due to the brown rot fungus Coniophora puteana (r = -0.64, p < 0.000) was lower than the correlation between the stilbene content and mass loss (r = -0.78, p < 0.000). Nonetheless, the method showed promise in separating the low and high mass loss samples from the average heartwood material. The fluorescence-based method may be utilized in timber grading and tree breeding, and due to the strong correlation between green and dry measurements, it may be applied at any stage of the processing chain.

Assessment of different sands potentiality to formulate an effective thermal energy storage material (TESM)

This paper presents a review of solid particles size effect on thermocline storage performance for Concentrating Solar Power (CSP) storage systems. After an overview on the different process to store thermal energy we found that a particle size of 2cm diameter is better to achieve a good sensible heat storage performance within a system call dual-medium thermocline (DMT). The thermal storage potentiality of different sands from Burkina Faso have been carry out to look at the possibility to make a filler material with 2cm diameter. However, two different sands (mining dune and river sand) properties have been assessed. The density of the two samples is more than 2650kg.𝑚−3 with low mass losses at 700 ℃ without any agglomeration at 900 ℃ and 1000℃. This indicates that the mining sand samples from Bobo Dioulasso and Dune sand from Sahel region in Burkina (Oursi) have the potentials to be used to develop an effective thermal energy storage material or to store thermal energy at high temperature.

Effect of potassium fertilizers associated with cold storage on peach (Prunus persica L.) quality

Potassium (K) fertilization may affect peach quality and preservation. This study aimed at evaluating the effect of doses of K on physico-chemical and functional characteristics of ‘Sensação’ peaches in the postharvest period. Mass loss, pulp color, total soluble solids, titratable acidity, pH, pulp and skin firmness, total concentrations of phenolic compounds and carotenoids and antioxidant activity were evaluated in fruits. The experiment was a randomized block design in a 5x3 factorial scheme, five doses of fertilizers (0, 40, 80, 120 and 160 Kg ha-1 K2O) and three storage periods (harvest day, 10 days and 20 days in cold storage at 1±1ºC, followed by a day of simulated commercialization at 20±1ºC). Mass loss, pulp firmness, phenolic compounds, antioxidant activity and carotenoids decreased when fruit underwent cold storage, independent of the dosage of K fertilization. Doses of 40 and 160 kg ha-1 K2O applied to the soil lead to a larger number of phenolic compounds and higher antioxidant activity in fruits at harvest time. After cold storage, fertilization with 160 kg ha-1 K2O exhibited the highest antioxidant activity and the lowest mass loss in fruits. Increase in doses of K strengthened the color of peach pulp

Active Packaging-Releasing System with Foeniculum vulgare Essential Oil for the Quality Preservation of Ready-to-Cook (RTC) Globe Artichoke Slices.

Two globe artichoke genotypes, “Spinoso sardo” and “Opera F1”, have been processed as ready-to-cook (RTC) slices and refrigerated at 4 °C for 12 days (i) to evaluate the suitability to be processed as RTC slices; (ii) to evaluate the effect of a Foeniculum vulgare essential oil (EO) emitter, within an active package system, to delay quality decay, thus extending shelf life; (iii) to estimate the impact of EO emitter on the sensory profile of the RTC slices after cooking. Results revealed that both globe artichoke genotypes possess a good attitude to be processed as RTC product. “Opera F1” showed the best performances for color parameters, texture and chemical indexes, while “Spinoso sardo” showed lower mass loss (ML) over the storage time. The addition of EO emitter slowed down the consumption of O2, better preserved texture when compared to the control and more effectively control polyphenol oxidase (PPO) activity and antioxidants’ retention during the cold storage. Microbial counts in control globe artichoke RTC slices were significantly higher than those packed with EO emitter, confirming the inhibiting role played by EO of F. vulgare. In addition, the EO emitter did not influence negatively the sensory profile of RTC globe artichoke slices after microwave cooking.

Stable isotope approaches to study muscle mass outcomes in clinical populations

Both low muscle mass and muscle loss are associated with reduced physical function, mobility, independence, and quality of life, and are characteristic of a number of clinical conditions including diabetes, cardiovascular disease (CVD), chronic obstructive pulmonary disease (COPD), and critical illness. The accurate measurement of muscle mass is critical to assess the efficacy of an intervention or therapy. Stable isotope amino acid approaches can be used to quantify specific aspects of whole-body and muscle protein turnover, including synthesis and breakdown, which play distinctive roles in muscle mass maintenance in direct response to therapies. This review aims to elucidate whether acute responses measured using stable isotope amino acid tracers relate to changes in muscle mass in vulnerable clinical populations. Experimental studies quantifying whole-body protein synthesis and breakdown rates in clinical populations have been conducted to determine the response to nutritional interventions or to compare disease with health; however, these studies show limited potential to translate to expected muscle mass outcomes. In addition, clinical studies that have assessed both muscle mass and acute changes in whole-body or muscle protein turnover are lacking. We argue that the assessment of both muscle protein synthesis and breakdown rates, or simply limb net balance, obtains the most complete picture in relation to muscle-specific outcomes. While stable isotope amino acid tracer experiments provide meaningful mechanistic insight into the acute response to clinical interventions, they should be combined with, and/or followed-up by, longer-term studies incorporating measurements of muscle mass to ascertain the impact of an intervention on muscle mass maintenance in clinical populations.

Comparison of thermal stability between dicyclopentadiene/hydrogenated dicyclopentadiene petroleum resin: Thermal decomposition characteristics, kinetics and evolved gas analysis by TGA/TG-MS

The thermal decomposition behavior and kinetics of dicyclopentadiene petroleum resin (DPR) and hydrogenated dicyclopentadiene petroleum resin (HDPR) were extensively explored. Both resins had two complex overlapping pyrolysis stages. The activation energy of DPR pyrolysis varied between 79−236 kJ mol−1. The pyrolysis of DPR mainly contained depolymerization accompanied by repolymerization. The main product was cyclopentadiene. By contrast, the initial pyrolysis rate of HDPR was relatively slow. The activation energy of HDPR pyrolysis ranged from 67−217 kJ mol−1. The pyrolysis process of HDPR is mainly ring opening and dehydrogenation reaction. Alkenes, alkynes and hydrogen were its main products. These results indicate DPR was easy to decompose and part of the molecule was changed to cross-linked reticular structure by the repolymerization at high temperature environment. Compared with that, HDPR has lower thermal mass loss rate and higher thermal structure stability.

Thermal characterizations of basalt fiber-reinforced poly(aryl-ether-ketone) biomedical composites

This research article deals with the development and characterization of poly(aryl-ether-ketone) (PAEK) reinforced with 10 mass%, 20 mass% and 30 mass% of basalt fibers; the samples are titled as PABA 1, PABA 2 and PABA 3, respectively. The composite samples are prepared by hot compression molding process, and test specimens are prepared to ASTM standards. The prepared specimens are subjected to various thermal analyses. The results reveal that differential scanning calorimetry curve shows high crystallization temperature and melting enthalpy for 20 mass% basalt fiber in PAEK composite compared to other composites. The percentage of crystallinity is also higher, which indicates the purity of PABA 2. The same composite shows low mass loss with increase in degradation temperature in the thermogravimetric analysis, due to high heat resistance capacity and thermal barrier of PAEK/basalt fiber at this particular mass%. Dynamic mechanical analysis of 20 mass% basalt fiber PAEK composite shows better storage modulus and low loss modulus compared to 10 and 30 mass% basalt fiber/PAEK composites. The PABA 2 composite has minimum damping coefficient which indicates better stiffness and suitability for high-performance applications. The scanning electron microscope images show a good affinity between the matrix and the fiber in all the composites. Agglomeration of fibers in matrix is observed when loaded beyond 20 mass%; this may be due to lack of melt flow during hot compression.

Improved Wear and Corrosion Resistance of Microarc Oxidation Coatings on Ti–6Al–4V Alloy with Ultrasonic Assistance for Potential Biomedical Applications

Although microarc oxidation is frequently used in producing wear‐ and corrosion‐resistant coatings on Ti and Ti alloys for biomedical applications, the formation of nonuniform microstructure of the coatings is still unavoidable. To overcome this drawback, this work adopts ultrasonic assistance in the microarc oxidation of Ti–6Al–4V and systematically investigates the influences of ultrasonic treatment with different durations on the coating microstructures and resultant properties. The positive effects of ultrasonic, such as cavitation effect, sound flow effect, and mechanical effect, accelerate the cooling rate of electrolyte and promote the homogeneity of the solute on the sample surface. Therefore, the ultrasonic‐assisted coatings exhibit uniform microstructures with fewer cracks and therefore improve performances. For instance, compared with the counterpart without ultrasonic assistance, the ultrasonic‐assisted coating with 15 min duration demonstrates 25.1% lower mass loss in the tribology test and half corrosion density in Hank's solution. Such results indicate that ultrasonic assistance in microarc oxidation of Ti–6Al–4V can homogenize the microstructures of coatings and enhance their corrosion resistance and wear resistance in human body.

Geomechanical, durability–hygrothermal and thermal shock properties of Kocaeli Kandira stone used as building stone in historical structures

This study investigated the mineralogical, chemical, physical, mechanical, durability–hygrothermal, thermal shock properties, and economic aspects of the Kandira stone, one of the well-known natural building stones, commonly used in many historical structures in the Marmara and Thrace regions. Especially, it has been preferred to Malta stone in historical structures in Istanbul due to economic reasons at the beginning of the 1900s. A similar appearance and lithology with Malta stone and closeness of the Kandira stone to Istanbul made it attractive to be used as natural building stone in historical monuments and new structures. The mean physico-mechanical properties of Kandira stone yielded 2.24 g/cm3 apparent density, 2.72 specific gravity, 19.21% total porosity, 5.8% water absorption by weight, 48 MPa compressive strength, 11.4 MPa bending strength. In terms of durability properties, Kandira stone has high resistance to aging by CaCl salt mist and no or low resistance to SO2 aging in a humid environment. Also, the freeze–thaw test of Kandira stone yielded an exceptionally low mass loss (0.11%) indicating that the stone is resistant to freeze–thaw effect. Thermal shock tests indicated that Kandira stone is mainly resistant to thermal shock cycles. Economically, the calculated probable reserve of Kandira stone resulted in 40.8 × 106 tons of material and the potential economic value based on the probable reserve is calculated around 54.672 × 109 TL (approximately €7.2B). In conclusion, this study defined the petrographic, geomechanical, durability–hygrothermal and thermal shock properties essential for the use of Kandira stone as building stone and restoration material.