• Journal of the Ergonomics Society of Korea
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• v.29 no.4
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• pp.639-646
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• 2010

The APAM's quantitative effectiveness and comparative study in preventing and treating pressure ulcer has not been sufficiently evaluated mainly because of uncertainty of pressure load input and lack of interpretation of dynamic perfusion recovery characteristics of soft tissue. The purpose of this paper was to quantify and analyze the alternating pressure characteristics of APAM as a preventive measure for pressure ulcers. To quantify the alternating load to human body, we introduced alternating pressure profile concept and developed parametric model of the profile. Regarding pressure level and cycle time, 3 global and 7 local periodic parameters were used to define the profile such as light, standard, typical and heavy duty profile shape. Pressure impulse ratio of light duty is the lowest but pressure fluctuation is significantly high. For the same duty shape, contact conditions are changed with alternating cycle time and more dramatically in shorter alternating cycle time conditions. We can conclude that if we use shorter alternating cycle time on APAM's operation we can get more positive effects regarding to inflated contact time condition. We proposed the quantitative methods on tissue viability study of external loading by simultaneous measurement of interface pressure and tissue perfusion with proper alternating pressure profile conditions.

• Journal of the Ergonomics Society of Korea
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• v.29 no.6
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• pp.875-887
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• 2010

The quantitative effectiveness of powered support surfaces such as APAM in preventing and treating pressure ulcers has not been sufficiently evaluated because of uncertainty of alternating pressure load input and lack of interpretation of dynamic perfusion characteristics of soft tissue. The aim was to verify the dynamic loading effects to sacral tissue perfusion characteristics from alternating set pressure changes. We developed integrated experiment system to supply alternating load to supinely positioned sacrum and concurrently measured $TcPO_2$, $TcPCO_2$ and air cell pressure. Ten aged subjects (5 female, 5 male) were tested with alternating set pressure 20, 30, 40, 50 and 60mmHg. From the dynamic perfusion response eight characteristic parameters were proposed such as average, minimum, maximum and perfusion range regarding to $TcPO_2$ and $TcPCO_2$. A one-way ANOVA was carried out to determine whether the manipulation of alternating set pressure had any effect on $TcPO_2$ and $TcPCO_2$. From the dynamic tissue perfusion response we found mean $TcPO_2$ decreased exponentially as alternating pressure load increased and perfusion range varied mainly because of minimum level change of $TcPO_2$. And perfusion range of $TcPCO_2$ affected by increase of maximum value of $TcPCO_2$. From the results we can get more strict insights about actual physiological dynamic tissue perfusion mechanism under alternating pressure load.

• Clean Technology
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• v.16 no.1
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• pp.39-45
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• 2010

In this paper, 4 bundle modules of PVDF hollow fiber membrane from Woori Tech company (Korea) were manufactured in a treatment capacity of 10 ton/day. A membrane bioreactor (MBR) pilot plant was installed at Sooyoung Wastewater Treatment Plant in Busan. An alternating aeration process was selected to avoid the concentration profile of suspended solid (SS) in the MBR. For stable operation, raw wastewater with mixed liquor suspended solid (MLSS) of about 1,000 ppm, which was in-flowed from the aeration tank of the wastewater treatment plant, was fed and filtered through the pilot plant. Subsequently the pilot plant were washed three times with washing water: once with ethanol solution, once with a solution of 5% NaOCl, and finally with washing water. After the chemical washing, the remaining water in the MBR was fed into the pilot plant. As a result, the SS removal efficiency was found to be more than 99.9%. The amount of filtrate with the aeration tank influent decreased by 16%, compared with that from the initial conditions, giving rise to 30% increase in the suction pressure. These results were used to set up continuous operation conditions. The results from the continuous operation with influent MLSS of 1,900 mg/L showed that the SS removal efficiency was about 99.99% and that the amount of filtrate and the suction pressure were $42{\sim}52L/m^2$ and 16~20 cmHg, respectively, indicating stable operation of the pilot plant. However, for the reuse of wastewater, methods need to be sought to avoid growth of algae which affects the SS removal efficiency at inlet and outlet of the permeate tank.

• Economic and Environmental Geology
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• v.57 no.1
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• pp.25-39
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• 2024

The Téra manganese deposit represents the most significant manganese mineralization discovered in Niger up today. The main host rocks of this ore are gondites, which are a garnet and quartz rich metamorphic rocks. The supergene weathering developed an alteration profile on these gondites. This study aims to identify the mineralogical composition of gondites and associated rocks, in order to highlight the origine of rocks and the manganese enrichment. The methodological approach adopted involved a field study followed by polarizing microscopic analysis using transmitted and reflected lights. Additionally, quantitative X-ray diffraction (XRD) analysis was performed to assess the manganese ore minerals present in the gondite and associated rocks, including mica schists, amphibolites, and quartzites. The petrographic study revealed a paragenesis characterized by the presence of kyanite, staurolites, garnets and plagioclases that are generally poikiloblasts with quartz and opaque minerals inclusions, emphasizing the internal schistosity which is planar, helicitic or microfolded. These features indicate a prograde metamorphism until high-pressure amphibolite facies conditions. These conditions are followed by greenschist facies conditions marked by calcite, epidote, muscovite, chlorite and muscovite assemblage which emphasizes the vertical tectonics. Depending on the alteration process, the manganese ore exhibit a granular texture at the bottom of the gondite hills, transitioning to a colloform texture towards the top, passing through the epigenization and replacement texture. The XRD analysis further revealed that the studied rocks originated from a volcano-sedimentary complex, characterized by alternating marly, arenaceous and pelitic sequences associated with submarine exhalations.