Effects Of Different Particle Sizes Research Articles

Variations in the life-cycle parameters and population growth of rotifer Brachionus plicatilis under the stress of microplastics and 17β-estradiol

The toxic effects of microplastics (MPs) on biota are related to their particle size. In addition, MPs could adsorb ambient pollutants in water, which increase the threat of MPs to organisms. In this study, the effects of different particle sizes and concentrations of MPs on the life-cycle parameters and population growth of rotifer Brachionus plicatilis were investigated, and the combined effects of MPs and 17β-estradiol (E2) on rotifers were studied. Results showed small particle size (50 nm) MPs had negative effects on the lifespan, time to first batch of eggs, fecundity, and population growth rate of rotifers, which were dose-dependent, but large (100 nm and 500 nm) MPs were not. In addition, both life-cycle parameters and the population growth of rotifers were not affected by E2. However, the combination effects of different particle sizes of MPs and E2 on the lifespan, reproductive period, offspring per female, and population growth of rotifers were significant. Therefore, rotifers were more vulnerable to smaller particle MPs, and the coexistence of MPs and other environmental pollutants posed a serious threat to rotifers.

Comparison of the Effects of 3D Printing Bioactive Porous Titanium Alloy Scaffolds and Nano-biology for Direct Treatment of Bone Defects.

This study was to compare the effects of three-dimensional (3D) printed bioactive porous titanium alloy scaffolds (3DP-BPTAS) and rhBMP-2/PLA-loaded sustained-release nanospheres (SRNs) in the treatment of bone defects. In this study, the bioactive porous titanium alloy scaffolds (BPTAS) with different pore sizes were prepared by selective laser melting (SLM) technology. The rhBMP-2/PLA SRNs were prepared by the double emulsion solvent volatilization method. The morphology of the two nanomaterials was observed under a scanning electron microscope (SEM). The encapsulation rate (ER), drug loading (DL), and in vitro release rate of the SRNs were detected by enzyme-linked immunosorbent assay (ELISA); and the effects of different particle sizes of BPTAS and SRNs on the proliferation of BMSCs were measured using the Methyl Thiazolyl Tetrazolium (MTT) method. 42 healthy male rabbits were selected and rolled into a control group (no treatment), a model group (the femoral condyle defect model), an A800 group (model + 800 μm of BPTAS), and an A1000 group (model + 1000 μm of BPTAS), an A1200 group (model + 1200 μm of BPTAS), an A1500 group (model + 1500 μm of BPTAS), and an SNR group (model + rhBMP-2/PLA SRNs). There were 6 rabbits in each group, and they were sacrificed 4, 8, and 12 weeks after the surgery. They were performed with general observation, X-ray photography, and histological and biomechanical examinations. According to the Lane-Sandhu bone defect repair tissue X-ray and histological scoring standard, the effect of bone defect repair was evaluated. It was found that the actual pore structure of the scaffold prepared by the SLM process was consistent with the theoretical design. The observation under TEM showed that rhBMP-2/PLA SRNs were approximately round, with an average particle size of 835 nm, and its encapsulation efficiency and drug loading rate were 89.02 ± 5.14% and 0.033 ± 0.004%, respectively. The rhBMP-2/PLA SRNs and BPTAS had no statistically obvious increase in the number of cells after cell treatment compared with the control group (P> 0.05). At 12 weeks postoperatively, the stent bone tissue growing distance (SBTGD) in the SRN group was longer than that in the A1000 group (P< 0.01), and that in the A1000 group was better in contrast to the A800, A1200, and A1500 groups (P< 0.01). The Lane-Sandhu X-ray score of the SRN group was better than other groups (P< 0.05). It suggested that 3DP-BPTAS and rhBMP-2/PLA SRNs could repair the bone defects, and rhBMP-2/PLA SRNs were more conducive to the formation of new bone tissue.

Effects of different particle size of spinel and Y2O3 additive of the periclase-spinel refractory on the sintering densification and corrosion resistance to copper smelting slag

In order to analyze the sintering densification and copper smelting slag corrosion resistance of periclase-spinel refractories, the periclase-spinel refractories were prepared with fused magnesia, magnesia-rich spinel, industrial alumina, and yttrium oxide as the main raw materials. The different particle sizes of spinel in material and with or without Y2O3 additive were studied. The study demonstrated that: (1) The different particle sizes of spinel in periclase-spinel refractories can result in different effects. Adding particle spinel to the refractory can improve the strength and corrosion resistance of the periclase-spinel refractories. The addition of spinel and magnesia powders in the matrix resulted in cracks due to the great difference of coefficient of thermal expansion between magnesia and spinel. The reduction in bulk density and strength of the material decreased slag penetration resistance because of its poor sintering properties. While adding the alumina in the matrix can further fill the crack and prevent slag penetration by the volume expansion of in-situ reaction to form spinel. (2) The periclase-spinel refractories can be reacted with Cu slag to form a Mg2FeO4 insulating layer as the iron ion becomes oxidized. Adding Y2O3 in periclase-spinel refractories can result in grain boundary phase reconstruction, which can promote sintering densification, improve the slag physical infiltration resistance, and improve the chemical corrosion resistance of materials.

Effect of Different Particle Sizes on The Akara Making Potentials of Pigeon Pea Flour

The study evaluated the potentials of Pigeon pea (Cajanus cajan) flour in the production of akara (fried cake). The flour samples were produced by soaking the seeds in water, dehulled, oven dried and ground to flour and divided into 4 units. The flour was passed through sieve of different size while the control was not sieved. Physicochemical and sensory analyses were conducted for the flour and akara using standard methods and results were presented as mean ± standard deviation using ANOVA. Significance was accepted for p≤0.05 by Duncan multiple range test. Result of functional properties showed that the sieved pigeon pea bulk density, emulsion capacity and foam capacity increased with increase sieve aperture in the range 0.73 to 0.81(g/mg), 43.08 to 46.66, and 44.35 to 46.14 respectively, while wettability (1.53 to 1.88) and gelation capacity (11.10 to 11.17) decreased. The results of the proximate composition of the akara showed values for pigeon pea and cowpea flours in moisture content, ash, fibre, protein and carbohydrates. The Sensory evaluation results showed that all the sensory parameters evaluated increased with decreased sieve aperture and differed significantly with respect to overall acceptability. Keywords: proximate, sensory, quality, cowpea

Effects of different particle size of zero-valent iron (ZVI) during anaerobic digestion: Performance and mechanism from genetic level

Although zero valent iron (ZVI) has been widely studied as an additive in anaerobic digestion, the effect of ZVI particle size on anaerobic methane production and the mechanism by which this occurs have not been reported. This study investigated the effects of ZVI particles with different diameters (0.1 μm to 250 μm) on the glucose-substrate anaerobic digestion process. It was found that different particle sizes of ZVI had different optimal dosages, as 2 g/L of 48 μm ZVI increased methane production by 84.12% when compared with the blank group, whereas ZVI of 0.1 μm reached its optimal dosage at 0.5 g/L, increasing methane production by only 37.32%. Further study of the mechanism showed that 4 μm ZVI could increase the abundance of bacteria Bacteroidota and Proteobacteria (from 1.46% and 0.07% to 15.56% and 2.27%, respectively) and Archaea Methanosaeta (from 3.59% to 51.64%). Gene’s prediction showed that ZVI particles with a size range of 4–48 μm could facilitate cell replication and increase enzyme activity involved in methane production. Additionally, it could mediate direct interspecies electron transfer between fermentative bacteria and methanogens while avoiding cell lysis caused by the nano effect.

Effects of Different Particle Sizes on the Bulk Density, Porosity Character, Water Suction of Substrates

研究粒径对栽培基质容重、孔性和水吸力的影响，以便为空间植物培养提供栽培基质。采用4种基质，即Profile基质（P）、黑陶粒（B）、白陶粒（W）和蛭石（V），各基质按照不同粒径（&lt; 1 mm，1~2 mm，2~3 mm）组成设置了10种组合（体积百分比），研究测试不同粒径组合基质的基本理化特性、容重、孔性和水吸力。P和B基质的容重约0.70 g·cm^–3。P基质含有较多矿质养分离子；增加小粒径基质颗粒占比，不同组合基质的容重、总孔隙度和持水孔隙度均显著增加，但通气孔隙度下降；在10种不同基质组合中，P7（40-60-0）、B8（10-70-20）和W4（10-60-30）分别具有最高的总孔隙度，P8（10-70-20），B1（20-50-30）和W8（10-70-20）具有最高的气水比，P3（50-50-0），B3（50-50-0）和W3（50-50-0）具有最高吸附水量；4种基质的平均总孔隙度和吸水量大小顺序为V&gt;P&gt;B&gt;W。因此，P3（50-50-0）基质和B7（40-60-0）基质具有适中的容重、良好的孔性和较高的水吸力，适用于空间植物栽培。

Application of Carbon Nanocomposite Sensing and Functional Magnetic Nanomaterial in the Sports Industry and Its Biosecurity Research

Nanomaterial science is a particularly important research field in modern science and technology, which has attracted wide attention and research from all walks of life since its inception and has formed a relatively perfect category of science and technology. The purpose of this paper is to explore the application of carbon nanocomposite sensing and functional magnetic nanomaterial in the sports industry and their biosecurity research. This paper first discusses the research progress of nanocomposite in biosecurity and concludes that chemical modification can reduce the negative biological effects of nanomaterial, then puts forward the research methods on nanocomposite in the sports industry, and then selects nanosilver composites to explore and study the effects of different particle sizes and concentrations on the antibacterial properties of Aspergillus and test and characterize the properties of nanocomposite. The stability of nanocomposite modification electrodes is also explored. The results show that nanosilver has excellent bactericidal effects on both AF293 and Gra04. In particular, 8.08 × 10−5 mol/L and 4.03 × 10−5 mol/L nanosilver has a bacteriological rate of 100%, indicating that the growth of all fungal spores can be completely inhibited, and when the content of 10 wt% is found, the thermal conductivity of PHBE‐MWNT pressure‐sensitive composite materials is achieved 0.6975 W/(m‐K), 1.8 times the MWNT pressure‐sensitive glue, higher than the pure pressure‐sensitive glue about 255%.

Particle Size Effect of Oyster Shell on Mortar: Experimental Investigation and Modeling.

In order to solve the problem of lack of natural river sand, crushed waste oyster shells (WOS) were used to replace river sand. By replacing 20% river sand, WOS mortar with different particle sizes of WOS were made for the experiment. Through experimental observation, the initial slump and slump flow loss rate were studied. The effects of different particle sizes and curing times on the compressive strength, flexural strength, static elastic modulus, and dry shrinkage of WOS mortar were analyzed. The relationship formulas between the compressive strength, flexural strength, particle size, and curing age were proposed. The results showed that the setting time and slump flow decreased with a decrease in the particle size of WOS. It was also found that the mortar with fine crushed WOS had high compressive strength, flexural strength, and static elastic modulus at both early and long-term curing age. A formula was proposed to describe the development of the compressive strength with the particle size of WOS and curing time, and the relations among these mechanical properties were discussed. Furthermore, drying shrinkage increased when WOS was used and could not satisfy the standard requirement of 0.075%. In contrast, the addition of fine WOS and double-dose sulfonated naphthalene-formaldehyde superplasticizer (SNF SP) reduced the shrinkage rate of the mortar by 8.35% and provided better workability and mechanical properties for mortar.

Effect of Particle Size on Color of Ground Coffee

Introduction: Particle size is one of the main variables that influence coffee brewing process and also most obvious to the consumers. The aim of this study was to evaluate the effect of different particle sizes on the color of ground coffee.&#x0D; Methods: A laser diffraction analyzer was used to determine the particle size distribution of the 14 dry ground coffee samples. The particle size distribution of the roasted ground coffee samples that underwent grinding at different time periods was based on volume distribution. Color measurements of all coffee samples were made using a portable CR-400 tristimulus colorimeter and Spectra-Match software, set to L*, a*, b* mode. Color measurements were recorded for two replicates of each sample.&#x0D; Results: Coffee samples ground for short times of 30s, 20s and 10s, were observed to have coarser particles than those that underwent longer grinding times. The 20s and 30s grinding times did not exhibit any significant differences for the D50 and D90 particle size distributions. There was no significant difference in D50 and D90 values for Colombian 1.3, Leyenda and Tarrazu brands. It was observed that lightness (L*) as well as a* and b* were highly significantly different between the different coffee samples with P &lt; 0.0001. The coffee samples that underwent grinding for 60s had the highest L*, a* and b* values of 30.72, +1.31 and +1.39 respectively. Colombian 1.3 coffee brand had the lowest L* and a* values of 29.8 and +0.67 respectively, with brand 1820a having the lowest b* value of +0.39.&#x0D; Conclusion: The results of this study show that there was no significant effect of particle size distribution of coffee samples on color of the ground coffee particles. L*, a* and b* values decreased during roasting, due to the darkening of the beans resulting from sugar caramelization and Maillard reactions.

Effects of Different Particle Sizes of Hydroxyapatite on the Distribution and Migration of Trace Elements (Copper and Cadmium) in a Smelter-Impacted Soil.

To study the remediation effect of hydroxyapatite with different particle sizes, a field in situ experiment was carried out by adding conventional hydroxyapatite (0.25 mm) and microhydroxyapatite (3 μm) and nanohydroxyapatite (40 nm) to the contaminated soil and planting Elsholtzia splendens. The distribution and migration of copper (Cu) and cadmium (Cd) in soil were investigated after 4 years. The results show that the application of three different particle sizes of hydroxyapatite significantly raise the soil pH, total phosphorus, and soil organic carbon. Moreover, the addition of hydroxyapatite can reduce the EXC fraction of Cu and Cd by 73.7%–80.1% and 20.8%–35.2%, respectively. In addition, the concentrations of Cu and Cd in >2 mm, 0.25–2 mm, 0.053–0.25 mm, and <0.053 mm aggregate are significantly increased. This improvement indicates that there are risks which may cause the increasing of total Cu and Cd in the soil where the pollution sources still exist. Furthermore, the content of soil colloid is significantly increased, and the colloidal Cu and Cd distribution percentage have been significantly increased by 49.9%–120% and 30.3%–181%. This result illustrates that the application of hydroxyapatite may greatly increase the possibility of colloid and dust migration of Cu and Cd.

Numerical study on settlement characteristics of inhalable particles in under-floor air distribution system

Particles deposited on the surface and floor will again enter the air in a suspended state due to airflow disturbance, which will threaten people's health. Thus, the purpose of this study is to explore the effects of different particle sizes on the settlement and trajectory of floor particles in the under-floor air distribution (UFAD) system. In this paper, the indoor temperature distribution and particle concentration of office room in Shanghai are simulated by numerical simulation, and verified by experiments. On the basis of ensuring that the numerical simulation results are consistent with the experimental results, the numerical model is used to further analyze the trajectory and settlement characteristics of particles with different sizes in the UFAD system. The results show that the particles less than 1 μm are easy to be suspended in the air under the influence of floor air supply, and the particles larger than 2.5 μm are less affected and mainly settle on the floor. Moreover, the particles close to the air inlet are easier to suspend, so the personnel stay area should keep a certain distance from the air inlet area. Finally, the mosquito coil smoke diffusion simulation is carried out to simulate the unsteady diffusion process of particles when there is particle pollution source on the floor. It is found that most mosquito coil particles could be discharged from the air outlet in 10 min.

Interaction between Strong Sound Waves and Cloud Droplets: Theoretical Analysis

AbstractRecently, strong sound wave was proposed to enhance precipitation. The theoretical basis of this proposal has not been effectively studied either experimentally or theoretically. On the basis of the microscopic parameters of atmospheric cloud physics, this paper solved the complex nonlinear differential equation to show the movement characteristics of cloud droplets under the action of sound waves. The motion process of an individual cloud droplet in a cloud layer in the acoustic field is discussed as well as the relative motion between two cloud droplets. The effects of different particle sizes and sound field characteristics on particle motion and collision are studied to analyze the dynamic effects of thunder-level sound waves on cloud droplets. The amplitude of velocity variation has positive correlation with sound pressure level (SPL) and negative correlation with the frequency of the surrounding sound field. Under the action of low-frequency sound waves with sufficient intensity, individual cloud droplets could be forced to oscillate significantly. A droplet smaller than 40 μm can be easily driven by sound waves of 50 Hz and 123.4 dB. The calculation of the collision process of two droplets reveals that the disorder of motion for polydisperse droplets is intensified, resulting in the broadening of the collision time range and spatial range. When the acoustic frequency is less than 100 Hz (at 123.4 dB) or the SPL is greater than 117.4 dB (at 50 Hz), the sound wave can affect the collision of cloud droplets significantly. This study provides a theoretical perspective of the acoustic effect on the microphysics of atmospheric clouds.

Investigating the Mechanical Behavior of 3D Printed PLA-Coco Coir Composites

It is quite amazing that the use of 3D printing techniques, especially the Fused Deposition Modelling (FDM) has delivered such significance in terms of cost reduction, time saver features where a different variety of thermoplastic and composite materials (Biodegradable and Non-biodegradable) are well developed. Different sectors have continually developed natural organic materials that are also both structurally composite in nature. Similarly, the use of different fibers that are abundantly accessible and considered as renewable resources which can be optionally combined with other biodegradable materials is a great challenge through the use of the FDM printing method. The study aims to determine the effect of different particle size and raster angle at a certain fiber concentration which could affect the mechanical properties of the composite by developing a printable composite filament made of Polylactic Acid (PLA) and Coco Coir materials using a filament maker and FDM printer. The composite filament was fabricated and optimized using a twin-screw extruder and 3D Devo Filament maker. 3D printing of samples for mechanical testing was conducted using three (3) raster angles (45o, 60o, and 75o) and various particle sizes of coco coir fiber reinforcement in the PLA matrix. Results showed that the &lt; 74μm particle size of the coco-coir exhibited a 24% and 175% increase in tensile strength and izod impact strength compared to the pure PLA at 60o and 75o raster angles, respectively. Likewise, the reinforcement of &lt;149μm particle size coco coir at 45o raster angle contributes to an increase of 4.8% flexural and 176% compressive strength compared to pure PLA. The study concludes that there is an improvement in the mechanical properties of the PLA-Coco Coir composite at a certain particle size and raster angle in 3D printing.

The dynamic variation of upconversion luminescence dependent on shell Yb3+ contents in NaYF4: Yb3+,Tm3+@NaYF4: Yb3+,Er3+ nanoparticles

In this study, a series of NaYF4:Yb3+, Tm3+@NaYF4:Yb3+, Er3+ core@shell nanocrystals with different sensitizer contents in the shell were synthesized by a facile solvothermal method to investigate the impact of sensitizer Yb3+ on the upconversion luminescence. Transmission electron microscopy (TEM) results show that all prepared nanocrystals are well-crystallized with a hexagonal phase and have a desirable size distribution. The particle size increases after shell coating as shown in TEM images; however, it changes a little for samples with different sensitizer contents in the shell. Therefore, the effect of different particle sizes on luminescence properties, which is caused by different Yb3+ contents, could be minimized. Subsequently, it was assumed that the luminescent center content (Er3+) is same in all samples and does not influence the emission spectrum differences. Therefore, we investigated the underlying upconversion luminescence mechanism by determining the sample’s fluorescence spectrum and assuming that the energy transfer mechanism occurred in all the samples. The results show that the green upconversion luminescence decay was faster than its red counterpart when the Yb3+ content was increased and samples were excited using a 980 nm pulse laser. The transient spectra measured at different times after the excitation pulse reveal the intensity ratio associated with the green to red upconversion luminescence. It was concluded that the back energy transfer (BET) process from Er3+ to Yb3+ led to a conversion of the green emissions into the red emissions, which was beneficial to the red upconversion and the electron relaxation from 4I11/2 to 4I13/2. Therefore, the red to green upconversion luminescence ratio increases significantly in samples highly doped with Yb3+.

PH Measurement of Cement-Based Materials: The Effect of Particle Size

Healthy reinforced concrete should be highly alkaline to safeguard the passive protective film for reinforcement of steel bars against corrosion. pH measurement is gaining importance in research of cement-based materials (CBMs), such as paste, mortar and concrete, as well as in structural health monitoring and forensic engineering applications. However, insufficient information is available regarding the most practical, economical and applicable quantitative pH measurement method for CBMs from the sampling to measurement stage. Existing recommended methods for measuring pH have many variables that need to be investigated to determine how they influence the pH value. Samples were recommended to be ground into very fine particles for pH measurement. Preparing very fine particles of CBMs is costly and time consuming, while larger particles, with sizes similar to sand particles, are easier to obtain, without needing special equipment. This study aims to investigate the effect of different particle sizes on the pH of cement mortar. Mortar specimens were crushed and sieved to obtain different ranges of particle sizes to measure the pH values. Results showed that specimens with large particle sizes (between 600 µm and 4.75 mm) can produce similar results to specimens with very fine particle sizes (&lt;600 µm) by increasing the solid-to-solvent ratio or the leaching time.

Effects of Activated Carbon on the Fate of Antibiotic Resistance Genes During Anaerobic Digestion of the Organic Fraction of Municipal Solid Waste

The organic fraction of municipal solid waste (OFMSW) has become one of the sources and reservoirs of antibiotic resistance genes (ARGs). It is essential to explore the fate of ARGs during biological treatment of OFMSW. Therefore, the changes in several types of ARGs and integron genes during anaerobic digestion of the OFMSW were analyzed by quantitative PCR. Furthermore, the effects of different particle sizes of activated carbon on the behaviors of the target genes and the potential microbial mechanisms of ARGs dynamics were investigated. The results showed that the total ARGs in the initial system were reduced after anaerobic digestion with or without the presence of activated carbon. The removal rate of the absolute abundance of total ARGs was 29.95%-63.40%. In the final system of anaerobic digestion of the OFMSW, the abundance of total ARGs in powdered activated carbon (PAC) groups was significantly higher than that in the control group (P<0.05). The supplementation of PAC inhibited the reduction of ARGs, and the supplementation of granular activated carbon had no significant effect on the change in ARGs. The potential host bacteria of ARGs were mainly Clostridia, Bacteroidia, and Synergistia during anaerobic digestion. The enrichment of host bacteria caused by PAC addition was the main reason for the increase in the target genes. Moreover, Clostridia might have been the main driving factor for the growth and decline of ARGs. These results will help us to understand the dissemination of ARGs and the impacts of activated carbon addition on ARGs during anaerobic digestion of the OFMSW.

Effect of Sawdust Particle Size on Physical, Mechanical, and Energetic Properties of Pinus durangensis Briquettes

Particle size is a physical property that sometimes limits the quality of briquettes, so it is recommended to use different sizes in mixtures for their manufacture. The objective of this research was to evaluate the effect of different particle sizes of sawdust in mixtures on some physical, mechanical, and energetic properties of briquettes made from Pinus durangensis sawdust, as well as set the ranges within the appropriate values found to obtain desired values. Three particle sizes were established (large, medium, and small), and 10 mixtures were prepared using different percentages of each particle classification. The particle density, volumetric swelling, compressive strength, impact resistance index (IRI), and gross calorific value of the briquettes were evaluated. For the determination of optimal mixtures, the surface response methodology was used under a three-factor simplex-lattice model. The particle density values were in the range 0.92 to 1.02 g cm−3 and the volumetric swelling was 0.96 to 3.9%. The highest resistance to compression was 37.01 N mm−1, and the IRI was found in the range of 53 to 107%. The gross calorific values were from 19.35 to 21.63 MJ kg−1. The selection of different particle sizes for the mixtures increases the quality of the briquettes.

Effect of carrier particle size on enrichment and shift in nitrifier community behaviors for treating increased strength wastewater.

In activated sludge systems, adding carriers can improve nitrifier enrichment. Different attachment area induced by different particle sizes of carriers may result in different nitrifier community. This research investigated the effect of different particle sizes of coal ash on nitrifier enrichment treating increased strength wastewater. Results indicated efficient nitrifying coal ash was obtained with smaller coal ash. The ammonia removal rates reached over 98%, which outclassed that in negative control (63.28%), and no nitrite accumulated in these systems under high nitrogen concentration of 1123.35mgN/L. The high-throughput sequencing assays indicated carriers changed the microbial community structure significantly, thus facilitated the nitrification capacity. Increase abundance of nitrifier has a negative correlation with particle size of carriers. Nitrosomonas became the biggest beneficiary, which maximum composed 50.29% in fillers system and only 13.69% in negative control, whereas the number of Nitrobacter (less than 3.04%) became much lower than ammonia-oxidizing bacteria (AOB). However, the shift of microbial structures, large number of Dokdonella for instance, may guarantee the complete nitrification in systems with smaller carriers. Batch experiments showed a high dissolved oxygen (DO) concentration (4mg/L) and slightly alkaline condition (pH 8.0) had a positive effect on nitrifying coal ash. PRACTITIONER POINTS: The increase size of nitrifier has a negative correlation with particle size of coal ash. The smaller coal ash reduces the adverse effect of high nitrogen on nitrification. The ammonia removal rate reached 99.82% with influent of 1123.35mg /L in the smallest carriers system.

Ghanaian Cocoa (Theobroma cacao L.) Bean Shells Coproducts: Effect of Particle Size on Chemical Composition, Bioactive Compound Content and Antioxidant Activity

The worldwide cocoa bean shell (CBS) generation is estimated at around 900,000 tons. In their composition, this coproduct showed several bioactive compounds like methylxanthines or polyphenolic compounds. Thus, the aim of this work was to investigate the effects of different particle sizes on the chemical composition, physico-chemical, bioactive compounds content, and antioxidant properties of flours obtained from cocoa (Theobroma cacao L.) bean shells. The flours obtained from CBS with different particle sizes had high content of dietary fiber (61.18–65.58 g/100 g). The polyphenolic profile identified seven compounds being epicatechin and catechin (values ranged 4.56–6.33 and 2.11–4.56 mg/g, respectively) as the most abundant compounds. Additionally, the methylxanthines theobromine and caffeine were quantified with values ranging from 7.12 to 12.77 and 4.02 to 6.13 mg/g, respectively. For the fatty acid profile, the principal compounds identified were oleic, stearic and palmitic acids. CBS had antioxidant capacity with all methods assayed. For DPPH, ABTS and FRAP assays values ranged between 2.35–5.53, 3.39–11.55, and 3.84–7.62 mg Trolox equivalents/g sample, respectively. This study suggests that cocoa bean shells may constitute a valuable coproduct for the food industry due to its high content in valuable bioactive compounds.

Improvement in machining process performance using solid lubricant assisted minimum quantity lubrication

ABSTRACT To improve the quality of the product produced considering productivity, it is important to evaluate the factors affecting the machining experimentally and analytically. Looking at the harmful effects of conventional cutting fluid on the environment and workers’ health, in the current research work effort has been made to explore the effectiveness of minimum quantity lubrication (MQL) and solid lubricant in machining. Micron-sized calcium fluoride (CaF2) solid lubricant powder particles are mixed in SAE 40 cutting oil and applied to the machining area with minimum quantity lubrication. The effect of different particle sizes and wt% of CaF2 has been analysed by measuring surface roughness, chip-tool interface temperature, flank wear of the tool, and cutting forces. Results demonstrated that the smaller size and 20 wt% of CaF2 powder have improved the process performance by lowering surface roughness and tool wear. The effectiveness of solid lubricant can be viewed as an alternative compared to wet machining. The results can be used by related industries to improve machining performance with the use of MQL and solid lubricants leading towards clean and sustainable manufacturing.