• Journal of Animal Science and Technology
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• v.64 no.6
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• pp.1046-1062
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• 2022

This study investigated the effects of L-glutamine (Gln) supplementation on growth performance, physiological traits, heat shock proteins (HSPs), and gene expression related to muscle and adipose tissue development in Hanwoo steers under heat stress (HS) conditions. Eight Hanwoo steers (initial body weight [BW] 570.7 ± 43.6 kg, months of age 22.3 ± 0.88) were randomly separated into two groups, control and treatment, and supplied with the concentration (1.5% of BW kg/day/head) and rice straw (1.5 kg/day/head). The treatment group were fed the Gln supplementation (0.5% of concentration, as-fed basis) once a day at 08:00 h. Blood samples for the assessment of haematological and biochemical parameters and the separation of peripheral blood mononuclear cells (PBMCs) were collected four times, at 0, 3, 6, and 10 weeks of the experiment. Feed intake was measured daily. BW to analyze growth performance and hair follicle collection to analyze the expression of HSPs were executed four times at 0, 3, 6, and 10 weeks. To analyze gene expression, longissimus dorsi muscle samples were collected by biopsy at the end of the study. As a result, growing performance, including final BW, average daily gain, and gain-to-feed ratio, were not different between the two groups. Leukocytes including lymphocytes and granulocytes, tended to increase in the Gln supplementation group (p = 0.058). There were also no differences in biochemical parameters shown between the two groups, except total protein and albumin, both of which were lower in the Gln supplementation group (p < 0.05). Gene expressions related to muscle and adipose tissue development were not different between the two groups. As temperature-humidity index (THI) increased, HSP70 and HSP90 expression in the hair follicle showed a high correlation. HSP90 in the hair follicle was decreased in the treatment group compared with the control group at 10 weeks (p < 0.05). Collectively, dietary Gln supplementation (0.5% of concentration, as-fed basis) may not be influential enough to affect growth performance and gene expression related to muscle and adipose tissue development in steers. However, Gln supplementation increased the number of immune cells and decreased HSP90 in the hair follicle implying HS reduction in the corresponding group.

• Animal Bioscience
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• v.36 no.1
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• pp.132-143
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• 2023

Objective: The aim was to study the influence of cooling milk at 9℃ at the farm versus keeping it at 20℃ on Parmigiano Reggiano cheese lipolysis. Methods: A total of six cheesemaking trials (3 in winter and 3 in summer) were performed. In each trial, milk was divided continuously into two identical aliquots, one of which was kept at 9℃ (MC9) and the other at 20℃ (MC20). For each trial and milk temperature, vat milk (V-milk) and the resulting 21 month ripened cheese were analysed. Results: Fat and dry matter and fat/casein ratio were lower in MC9 V-milk (p≤0.05) than in MC20. Total bacteria, mesophilic lactic acid and psychrotrophic and lipolytic bacteria showed significant differences (p≤0.05) between the two V-milks. Regarding cheese, fat content resulted lower and crude protein higher (p≤0.05) both in outer (OZ) and in inner zone (IZ) of the MC9 cheese wheels. Concerning total fatty acids, the MC9 OZ had a lower concentration of butyric, capric (p≤0.05) and medium chain fatty acids (p≤0.05), while the MC9 IZ had lower content of butyric (p≤0.05), caproic (p≤0.01) and short chain fatty acids (p≤0.05). The levels of short chain and medium chain free fatty acids (p≤0.05) were lower and that of long chain fatty acids (p≤0.05) was higher in MC9 OZ cheese. The principal component analysis of total and free fatty acids resulted in a clear separation among samples by seasons, whereas slight differences were observed between the two different milk temperatures. Conclusion: Storing milk at 9℃ at the herd affects the chemical composition of Parmigiano Reggiano, with repercussion on lipolysis. However, the changes are not very relevant, and since the cheese can present a high variability among the different cheese factories, such changes should be considered within the "normal variations" of Parmigiano Reggiano chemical characteristics.

• Wind and Structures
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• v.34 no.1
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• pp.115-125
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• 2022

The high-Reynolds number flow around a rectangular cylinder, having streamwise to crossflow length ratio equal to 5 is analyzed in the present paper. The flow is characterized by shear-layer separation from the upstream edges. Vortical structures of different size form from the roll-up of these shear layers, move downstream and interact with the classical vortex shedding further downstream in the wake. The corresponding mean flow is characterized by a recirculation region along the lateral surface of the cylinder, ending by mean flow reattachment close to the trailing edge. The mean flow features on the cylinder side have been shown to be highly sensitive to set-up parameters both in numerical simulations and in experiments. The results of 21 Large Eddy Simulations (LES) are analyzed herein to highlight the impact of the lateral mean recirculation characteristics on the near-wake flow features and on some bulk quantities. The considered simulations have been carried out at Reynolds number Re=DU_∞/ν=40 000, being D the crossflow dimension, U_∞ the freestream velocity and ν the kinematic viscosity of air; the flow is set to have zero angle of attack. Some simulations are carried out with sharp edges (Mariotti et al. 2017), others with different values of the rounding of the upstream edges (Rocchio et al. 2020) and an additional LES is carried out to match the value of the roundness of the upstream edges in the experiments in Pasqualetto et al. (2022). The dimensions of the mean recirculation zone vary considerably in these simulations, allowing us to single out meaningful trends. The streamwise length of the lateral mean recirculation and the streamwise distance from the upstream edge of its center are the parameters controlling the considered quantities. The wake width increases linearly with these parameters, while the vortex-shedding non-dimensional frequency shows a linear decrease. The drag coefficient also linearly decreases with increasing the recirculation length and this is due to a reduction of the suctions on the base. However, the overall variation of C_D is small. Finally, a significant, and once again linear, increase of the fluctuations of the lift coefficient is found for increasing the mean recirculation streamwise length.

• Korean Journal of Environmental Agriculture
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• v.42 no.3
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• pp.203-210
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• 2023

Ferimzone Z is a fungicide for effectively controlling rice blast. Under light irradiation conditions, it undergoes a rapid conversion to its E-stereoisomer. Given the importance of isomers in risk assessments of residues in crops, an analytical method was developed for individual isomer quantification. A comparative analysis performed using two columns in HPLC-MS/MS demonstrated that the isomers were successfully separated using the Cadenza column. For the brown rice sample preparation, 5 g of the homogenized sample was saturated with 7 mL of water. The sample was then extracted with a 10 mL mixed solvent of acetonitrile and ethyl acetate (1:1, v/v) that contained 0.1% formic acid, and it was subsequently partitioned with magnesium sulfate and sodium chloride. The upper layer was purified using dSPE containing C₁₈ and PSA sorbents. The established method was subjected to method validation, and it showed recovery rates of 90.6-98.8% (RSD ≤ 3.9%) at concentrations of 0.01, 0.1, 2 mg/kg, with a soft matrix effect (%ME) ranging from -3.1% to +6.5%. This method can be employed in monitoring studies of brown rice to determine the conversion ratio from the Z isomers to the E isomers.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.285-290
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• 2023

Poly-lactic acid (PLA) is the most promising polymer in additive manufacturing as an alternative to acrylonitrile butadiene styrene (ABS). Since it is produced from renewable resources such as corn starch and sugar beets, it is also biocompatible and biodegradable. However, PLA has a couple of issues that limit its use. First, it has a comparatively low glass transition temperature of around 60 ℃, such that it exhibits low thermal resistance. Second, PLA has low impact strength because it is brittle. Due to these problems, scientists have found methods to improve the crystallinity and ductility of PLA. Polyethylene glycol (PEG) is one of the most studied plasticizers for PLA to give it chain mobility. However, the blend of PLA and PEG becomes unstable, and phase separation occurs even at room temperature as PEG is self-crystallized. Thus, it is necessary to investigate the optimal mixing ratio of PLA-PEG at the molecular scale. In this study, molecular dynamics will be conducted with various ratios of L-type PLA (PLLA) or DL-type PLA-PEG (PDLA-PEG) systems by using BIOVIA Materials Studio.

• Resources Recycling
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• v.32 no.2
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• pp.3-11
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• 2023

The aim of this study was to develop a physical treatment method for obtaining iron concentrate with a grade higher than 60% from slag generated in the Waelz Kiln (WK) process. The size of the WK slag used in this work was several millimeters, with T-Fe and ZnO contents of 40.24% and 1.03%, respectively. The slag samples were pulverized in a laboratory rod mill for various grinding times, followed by a magnetic separation test under a low magnetic intensity of 0.05 T initially. The results showed that the highest iron grade was obtained from samples with a grinding time of 10 min. Additionally, for a grinding time of 20 min, the highest grade and recovery ratios were achieved at a magnetic intensity of 0.8 T. Based on these findings, the optimal physical treatment process proposed in this study resulted in iron concentrates with a grade of 61.34% and an enrichment ratio of 1.52.

• Composites Research
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• v.36 no.3
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• pp.180-185
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• 2023

This paper investigates the impact of fiber dispersion on the internal structure and mechanical strength of SiC_f/SiC composites manufactured using spread SiC fibers. The fiber volume ratio of the specimen to which spread SiC fiber was applied decreased by 9%p compared to the non-spread specimen, and the resin slurry impregnated between the fibers more smoothly, resulting in minimal matrix porosity. In order to compare the fiber dispersion of each specimen, a method was proposed to quantify and evaluate the separation distance between fibers in composite materials. The results showed that the distance between fibers in the spread specimen increased by 2.23 ㎛ compared to the non-spread specimen, with a significant 42.6% increase in the distance between fiber surfaces. Furthermore, the 3pt bending test demonstrated a 49.3% higher flexural strength in the spread specimen, accompanied by a more uniform deviation in test data. These findings highlight the significant influence of SiC fiber dispersion on achieving uniform densification of the SiC_f/SiC matrix and increasing mechanical strength.

• Elastomers and Composites
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• v.37 no.4
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• pp.244-257
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• 2002

A thermotropic liquid crystalline polymer(TLCP) which has flexible butylene/hexylene spacers in the main chain and a triad aromatic ester type mesogenic unit containing a naphthyl group was prepared by solution polycondensation. The in-situ composites based on poly(ethylene 2,6-naphthalate) (PEN) and a thermotropic liquid crystalline polymer(TLCP) were prepared and melt spun at different TLCP contents and different draw ratios to produce monofilaments. Blends of the TLCP with PEN were investigated in terms of thermal, mechanical properties and morphology. The TLCP synthesized showed nematic mesophasic behavior and its transition temperature to isotropic melt from mesophase was 249℃. The blends showed well dispersed TLCP phases in the PEN matrix without macroscopic phase separation. Inclusion of TLCP in the blends decreased the cold crystallization temperature of PEN in the blend, therefore, the TLCP acts as a nucleating agent in the blend and showed good interfacial adhesion between the dispersed LCP phases and PEN matrix with domain sizes 40~50 nm in diameter and well developed fibrillation in the monofilaments. The TLCP acted effectively as a reinforcing material in the PEN matrix at the 10wt% level, it led to an increase of initial modulus up to 270% and tensile strength by 235%, while the elongation rate increasing with higher draw ratios.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1B
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• pp.35-45
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• 2009

In this study, a laboratory experiment has been performed on a S-curved channel with two curved sections. In the experiments, effects of 3-D velocity structures on mixing characteristics of tracer material were investigated. As a result, it was clearly noticed that the primary flow travels taking the shortest course of the meandering channel and has a very ununiform distribution at the bends. The secondary cell which was developing at the first bend disappears at the crossover, and then, at the next bend, secondary cell is re-developing in the opposite direction. The experimental results show that mixing of tracer is significantly affected by the combined action of ununiform primary flow and secondary cell. The ununiform primary flow separates the tracer cloud in the longitudinal direction, and the secondary cell further separates the retarding tracer cloud mainly in the transverse direction. As a result, these complex flow structures cause separation and spreading of tracer cloud both in the longitudinal and in the transverse directions. The measured dimensionless transverse dispersion coefficients calculated using 2-D routing procedure ranges 0.012-0.875, and is generally proportional to width to depth ratio (W/h). The predicted values calculated by the theoretical equation overestimate slightly the measured transverse dispersion coefficients.

• Korean Journal of Food Science and Technology
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• v.45 no.5
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• pp.537-544
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• 2013

This study was performed to establish method of simultaneous determination of fructose, glucose, and sucrose in honey and commercial vitamin drinks by GC and GC/MS. Optimum chromatographic separation of trimethylsilyl-oxime (TMSO) derivatives by GC was achieved on a DB-5 column. Calibration curves for fructose, glucose and sucrose TMSO derivatives by GC were linear in the range of 50-5000 ${\mu}g/mL$, and their $r^2$ values were 0.9999, The limit of detection and limit of quantification of fructose, glucose, and sucrose were 0.68, 0.47, and 0.53 ${\mu}g/mL$, respectively, and 2.27, 1.58, and 1.77 ${\mu}g/mL$, respectively. Average recoveries of fructose, glucose, and sucrose were 100.5, 101.0, and 99.7%, respectively. When the method was applied to 12 honey samples, the average concentrations of fructose, glucose and sucrose were $42.58{\pm}1.97%$, $27.74{\pm}1.16%$, and $0.79{\pm}0.52%$, respectively. The F/G ratio was $1.53{\pm}0.07$. For fructose and glucose contents, results from the GC analysis were similar to those from the HPLC analysis, but the sucrose content was different for each analysis method. We suggest that the GC method is more suitable than other official analytical methods for simultaneous determination of fructose, glucose, and sucrose in honey.