• Applied Chemistry for Engineering
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• v.5 no.4
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• pp.698-705
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• 1994

The basic medium oil modified alkyd resin was synthesized from linseed oil fatty acid(LOFA), phthalic anhydride(PAA), maleic anhydride(MA) and trimethylol propane(TMP) by condensation polymerization at $230^{\circ}C$. MA/TMPTA modified water-reducible alkyd resins were synthesized with TMPTA graft copolymerization onto the basic resin at $180^{\circ}C$. Acid value of the resin was controlled by the addition amount of MA and N,N-dimethylethanol amine(DMEA) was used as a neutralizing agent to prepare of the water-reducible alkyd resin. The effect of TMPTA on the graft copolymerization of the resin was studied by measuring molecular weight glass transition temperature(Tg), viscosity, graft efficiency, and gel contents of melanin cured film. Heat resistance, UV resistance and water resistance of cured film of MA/TMPTA modified resin was compared to those of TMA/TMPTA modified alkyd resin. The molecular weight, viscosity gel contents and graft efficiency of water reducible alkyd resin were increased according to the TMPTA graft copolymerization, but Tg was decreased. The viscosity was lower when the solid contents reached 40% than that of 30% content and also and also became lower with the extent of neutralization ratio, The heat resistance, UV resistance and water resistance of the MA/TMPTA modified alkyd resis were better than those of TMA/TMPTA modified alkyd resin but the storage stability of the TMA/TMPTA alkyd resis was better than that of MA/TMPTA modified alkyd resin.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.3
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• pp.327-334
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• 2011

It is necessary that UGV(Unmanned Ground Vehicle) should generate a real-time travesability index map by analyzing raw terrain information to travel autonomously tough terrain which has various slope and roughness values. In this paper, we propose a local path planning method, $MA^*$(Modified $A^*$) algorithm, using DVGM (Directional Velocity Grid Map) for unmanned ground vehicle. We also present a path optimization algorithm and a path smoothing algorithm which regenerate a pre-planned local path by $MA^*$ algorithm into the reasonable local path considering the mobility of UGV. Field test is conducted with UGV in order to verify the performance of local path planning method using DVGM. The local path planned by $MA^*$ is compared with the result of $A^*$ to verify the safety and optimality of proposed algorithm.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.19 no.2
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• pp.61-65
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• 2013

Modified atmosphere (MA) of reduced $O_2$ and elevated $CO_2$ concentrations has been used for keeping the quality of fresh produce and extending the shelf life. As a way to attain the beneficial MA package around the produce, a gas diffusion tube or perforation can be attached onto the container and controlled on real time in its opening/closing responding to $O_2$ and $CO_2$ concentrations measured by gas sensors. The timely-controlled opening of the gas diffusion tube can work in harmony with the produce respiration and help to create the desired MA. By use of the mathematical modeling, the effect of tube dimension on the controlled container atmosphere was figured out in this study. Spinach and king oyster mushroom were used as typical commodities for designing the model container system (0.35 and 0.9 kg in 13 L, respectively) because of their respiration characteristics and the optimal MA condition ($O_2$ 7~10%/$CO_2$ 5~10% for spinach; $O_2$ 2~5%/$CO_2$ 10~15% for mushroom). With a control logic for the gas composition to stay as close as possible to optimum MA window without invading injurious low $O_2$ and/or high $CO_2$ concentrations, the atmosphere of the sensor-controlled container could stay at its lower $O_2$ boundary or upper $CO_2$ limit under certain tube dimensional conditions. There were found to be the ranges of the tube diameter and length allowing the beneficial MA. The desired range of the tube dimension for spinach consisted of combinations of larger diameter and shorter length in the window of 0.3~2 cm diameter and 0.2~10 cm length. Similarly, that for king oyster mushroom was combinations of larger diameter and shorter length in the window of 0.9~2 cm diameter and 0.2~3 cm in length. Clear picture on generally affordable tube dimension range may be formulated by further study on a wide variety of commodity and pack conditions.

• Clinics in Shoulder and Elbow
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• v.12 no.2
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• pp.207-214
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• 2009

Purpose: In arthroscopic rotator cuff repairs there are generally weak link in tendon suture interface, arthroscopic rotator cuff repairs can have higher retear rates than open repairs. The purpose of this study was to compare the strength of UU (Ulsan University) suture than open modified MA (Mason-Allen) suture when suture anchored into bone. Materials and Methods: The human supraspinatus tendons were harvested from the shoulder of the cadaver and split in 2 times, producing four tendons per one shoulder, for a total of 24 specimens. Two suture configurations (UU, MA) were randomized and checked on each set of tendons. Specimens were cyclically loaded under force control between 5 and 30 N at 0.25 Hz for fifty cycles. Each specimen was loaded to failure under displacement control at 1 mm/sec. Cyclic elongation, peak to peak displacement, stiffness, ultimate tensile load, mode of failure were checked. Results: No significant difference was found between two suture configuration with respect to peak to peak displacement, cyclic elongation, and stiffness. With regard to ultimate failure load, there were no significant difference statistically between the UU suture and modified MA suture (109.4 N, 110.6 N). The most common mode of failure between both sutures was suture pull-out through the tendon. Conclusion: The UU suture and modified MA suture produced similar biomechanical properties.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.3
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• pp.428-434
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• 2012

The aim of this study was to determine the quality of modified atmosphere (MA) packaged meat from Pomeranian rams slaughtered at 50 and 100 days of age. Determined: chemical composition, physicochemical and sensory properties of meat, and the fatty acid profile of intramuscular fat. Meat from 100-d-old lambs was characterized by a significantly higher content of dry matter, total protein and crude fat, a darker color and higher physiological maturity ($p\leq0.01$). Meat from younger lambs was marked by a better water-holding capacity ($p\leq0.05$), a lower energy value and higher concentrations of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA). An increase in the content of dry matter, total protein and ash, and energy value was noted in MA-stored meat. Meat pH decreased over MA storage and the sensory properties deteriorated. The studied meat remained safe from microbial contamination during storage.

• Journal of Power Electronics
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• v.15 no.2
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• pp.346-355
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• 2015

On the basis of the conventional PID control algorithm, a modified adaptive PID (MA-PID) control algorithm is presented to improve the steady-state and dynamic performance of closed-loop systems. The proposed method has a straightforward structure without excessively increasing the complexity and cost. It can adaptively adjust the values of the control parameters ($K_p$, $K_i$ and $K_d$) by following a new control law. Simulation results show that the line transient response of the MA-PID is better than that of the adaptive digital PID because the differential coefficient $K_d$ is introduced to changes. In addition, experimental results based on a FPGA indicate that the MA-PID control algorithm reduces the recovery time by 62.5% in response to a 1V line transient, 50% in response to a 500mA load transient, and 23.6% in response to a steady-state deviation, when compared with the conventional PID control algorithm.

• Food Science and Preservation
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• v.31 no.1
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• pp.24-32
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• 2024

This study evaluates the microbial safety of ginseng sprouts packaged in moss and a modified atmosphere (MA) film within Styrofoam boxes. Ginseng sprout samples were stored at 4℃ for seven days, and the total fungi and aerobic bacteria counts, relative humidity, and moisture content were measured at 0, 1, 3, 5, and 7 days. During the storage period, both packaging treatments caused an increase in the total fungi and aerobic bacteria counts. However, by the seventh day, the ginseng sprouts packaged in the MA film demonstrated significantly lower counts of total fungi (3.03 log CFU/g) and aerobic bacteria (7.32 log CFU/g) than those in moss (3.66 and 7.63 log CFU/g, respectively). Moss packaging alone resulted in the total fungi count reaching up to 3.36 log CFU/g, with the aerobic bacteria count consistently exceeding 7 log CFU/g, highlighting the importance of hygienic management. Moreover, no significant differences were observed in the moisture content and relative humidity between the MA-film- and moss-packaged groups throughout storage. These findings indicate that the functional MA film is a more hygienic packaging solution for ginseng sprouts than moss.

• Membrane Journal
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• v.31 no.3
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• pp.219-227
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• 2021

Molecularly imprinted membrane (MIM) is a porous polymer membrane incorporating with the molecular recognizing sites. In this study, the supporting P(AN-co-MA) asymmetric membrane was prepared by nonsolvent induced phase separation (NIPS) method. And then, MIM with lysozyme template sites was prepared using the surface imprinting method on the P(AN-co-MA) asymmetric membrane introducing a photoactive iniferter and then photo-grafting. The P(AN-co-MA) asymmetric membrane was modified with 3-chloropropyltrimethoxysilane and dithiocarbamate as a photoactive iniferter. To prepare a lysozyme imprinted membrane, the modified P(AN-co-MA) membrane was copolymerized with acrylamide as a functional momomer, N,N'-methylene bisacrylamide as a crosslinker and lysozyme as a template in the UV irradiation environment. The lysozyme imprinted MIM was analyzed by using SEM, FT-IR and EDS measurements. Its results confirm that all the P(AN-co-MA) membranes have an asymmetric structure and the iniferter group is successfully introduced on the membrane surface. The process parameters were adjusted to obtain MIM having the excellent lysozyme adsorption. The maximum lysozyme adsorption capacity reaches at 2.7 mg/g, which is 13 times higher than that of the non imprinted membrane (NIM). The permselective membrane filtration experiments of ovalbumin to lysozyme show that the P(AN-co-MA) MIM preferentially bounds a greater amount of lysozyme.

• International Journal of Automotive Technology
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• v.6 no.6
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• pp.665-670
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• 2005

Nanocomposites of polypropylene with organically modified clays were compounded on a twin-screw extruder by two-step melt compounding of three components, i.e., polypropylene, maleic anhydride grafted polypropylene (PP-g-MA), and organically modified clay. The effect of PP-g-MA compatibilizers, including PH-200, Epolene-43, Polybond-3002, Polybond-3200, with a wide range of maleic anhydride (MA) content and molecular weight was examined. Morphologies of nanocomposites and their mechanical properties such as stiffness, strength, and impact resistance were investigated. X-ray diffraction patterns showed that the dispersion morphology of clay particles seemed to be determined in the first compounding step and the further dispersion of clays didn't occur in the second compounding step. As the ratio of PP-g-MA to clay increased, the clay particles were dispersed more uniformly in the matrix resin. As the dispersibility of clays was enhanced, the reinforcement effect of the clays increased, however impact resistance decreased.

• Journal of the Mineralogical Society of Korea
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• v.22 no.1
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• pp.63-72
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• 2009

Carbon-coated lithium iron phosphate ($LiFePO_4/C$) composites are synthesized by the modified mechanical activation method (modified MA process) and studied by the Rietveld structural refinement. Rietveld indices of $LiFePO_4/C$ indicate good fitting with $R_p=8.14%,\;R_{wp}=11.1%,\;R_{exp}=9.09%,\;R_B=3.88%$, and S (GofF, Goodness of fit) = 1.2, respectively. $LiFePO_4/C$ with a space group Pnma shows a = 10.3229(3)${\AA}$, b = 6.0052(2) ${\AA}$, c = 4.6939(1) ${\AA}$, and V = 290.98(1) ${\AA}^3$ in dimension, indicating good agreements with those of previous works. Synthetic powders are nano-sized ($65{\sim}90nm$) homogeneous particles with high purity. Thus the modified MA method will be an efficient process to get a high quality cathode material for commercial lithium batteries.