Strength of Partially Encased Steel-Concrete Composite Column for Modular Building Structures.

Modular structural systems have been used increasingly for low- and mid-rise structures such as schools and apartment buildings, and applications are extending to high-rise buildings. To provide sufficient resistance and economical construction of the high-rise modular structural system, the steel-concrete composite unit modular structure was proposed. The proposed composite unit modular system consists of the composite beam and the partially encased nonsymmetrical composite column. The outside steel member of the composite column has an open section, and is manufactured using a pressed forming procedure so that easy joining connecting work and manufacturing cost reductions are possible. However, the design methods are complicated due to the inherent nonsymmetrical properties of the section. Therefore, in this study, the focus was made on the strength evaluation and development of design methods for the partially encased nonsymmetrical steel-concrete composite column. Four full-scale specimens were constructed and tested. The experimental study focused on the effect of the slenderness ratio of the column, eccentricity, and the through bars on the strength of such columns. Additionally, the P-M interaction curve to estimate the strength of the proposed composite column under general combined loading was developed based on the plastic stress distribution method. The results indicate that the through bars are needed to delay the local buckling and distribute the loading uniformly throughout the composite column. Finally, the proposed design methods provide a conservative strength prediction of the proposed composite column.

Mercury adsorption characteristics of carbon sorbent with low surface area.

Several studies have been conducted to decrease the cost of sorbents used for the control of mercury emissions. Thus far, several sorbents with low surface areas have been reported to exhibit promising mercury removal capacities. However, based on the results reported, it is difficult to understand the mechanisms of adsorption and oxidization of elemental mercury on sorbents with low surface areas compared to those with higher surface areas. Three types of materials with different surface areas were evaluated herein for use as carbon sorbents for the adsorption of elemental mercury: (1) coal, (2) sewage sludge, and (3) unburned carbon. The respective raw sorbents and FeCl3-impreganted congeners were evaluated. Each sorbent was tested in a fixed-bed reactor system under two simulated flue gas conditions (1) without and (2) with 20 ppm hydrogen chloride (HCl). The injection of HCl increased the mercury adsorption efficiency of all tested sorbents by decreasing the emission of elemental mercury. Doping the sorbent with FeCl3 increased the mercury adsorption efficiency during the earlier test period under both simulated flue gas conditions (without and with HCl). FeCl3-impregnated activated carbon and FeCl3-impregnated unburned carbon emitted large amounts of oxidized mercury during the later test periods.Implications: We tested three types of sorbents to investigate the mercury adsorption characteristics of sorbents with low surface area. The mercury adsorption test was conducted by varying the raw material of the sorbent, chemical impregnation of the sorbent and the simulated flue gas composition. We found that HCl in simulated flue gas increased the mercury adsorption efficiency of both the raw and FeCl3-impregnated sorbents by decreasing the emission of elemental mercury.

Structure and arrangement of perforated plates for uniform flow distribution in an electrostatic precipitator.

A wide-angle diffuser installed at the entrance of an electrostatic precipitator (ESP) causes a non-uniform flow distribution due to the boundary layer separation. Because a non-uniform flow pattern decreases the particulate matter control efficiency of an ESP, it is important to maintain a uniform flow distribution. The objective of this study is therefore to understand flow distribution with the conditions of perforated plates placed in the diffuser and then to design an ESP to obtain uniform flow. Discharge coefficients were determined varying the porosity, thickness, and number of holes of the perforated plate inside the lab-scale duct system. The test results suggest that the perforated plate with a porosity of 50%, a thickness of 5 mm, and 0.104 hole/m2 perforated plate is most acceptable. This perforated plate was placed in the diffuser of the lab-scale ESP system. Velocity profiles in the body of the ESP were obtained depending on the number and arrangement of perforated plates in the diffuser. One perforated plate placed in the diffuser did not improve the flow distribution. Although more uniform flow distribution was found with two perforated plates, stalled flow regions still existed at the top and bottom of the ESP body. When three perforated plates were placed in the diffuser, the 2nd and 3rd perforated plates were important to obtain uniform flow distribution. When the 2nd and 3rd perforated plates were placed at the inlet side and outlet of the diffuser, respectively, the most uniform flow distribution was obtained in the body of the ESP.Implications: In order to determine the optimal perforated plate for Electrostatic Precipitator (ESP), we investigated the discharge coefficient depending on the structure of the perforated plate in a square duct. We measured the velocity distribution in a laboratory ESP with perforated plates and found the effect of the number and arrangement of perforated plates on the flow distribution in the collection region. Based on the test results, we found the configuration of perforated plates for uniform flow distribution in the body of the ESP.

Adsorption of mercury by activated carbon prepared from dried sewage sludge in simulated flue gas.

Conversion of sewage sludge to activated carbon is attractive as an alternative method to ocean dumping for the disposal of sewage sludge. Injection of activated carbon upstream of particulate matter control devices has been suggested as a method to remove elemental mercury from flue gas. Activated carbon was prepared using various activation temperatures and times and was tested for their mercury adsorption efficiency using lab-scale systems. To understand the effect of the physical property of the activated carbon, its mercury adsorption efficiency was investigated as a function of its Brunauer-Emmett-Teller (BET) surface area. Two simulated flue gas conditions, (1) without hydrogen chloride (HCl) and (2) with 20 ppm HCl, were used to investigate the effect of flue gas composition on the mercury adsorption capacity of activated carbon. Despite very low BET surface area of the prepared sewage sludge activated carbons, their mercury adsorption efficiencies were comparable under both simulated flue gas conditions to those of pinewood and coal activated carbons. After injecting HCl into the simulated flue gas, all sewage sludge activated carbons demonstrated high adsorption efficiencies, that is, more than 87%, regardless of their BET surface area. IMPLICATIONS: We tested activated carbons prepared from dried sewage sludge to investigate the effect of their physical properties on their mercury adsorption efficiency. Using two simulated flue gas conditions, we conducted mercury speciation for the outlet gas. We found that the sewage sludge activated carbon had mercury adsorption efficiency comparable to pinewood and coal activated carbons, and the presence of HCl minimized the effect of physical property of the activated carbon on its mercury adsorption efficiency.

Nitrogen oxides emissions from the MILD combustion with the conditions of recirculation gas.

The nitrogen oxides (NOx) reduction technology by combustion modification which has economic benefits as a method of controlling NOx emitted in the combustion process, has recently been receiving a lot of attention. Especially, the moderate or intense low oxygen dilution (MILD) combustion which applied high temperature flue gas recirculation has been confirmed for its effectiveness with regard to solid fuel as well. MILD combustion is affected by the flue gas recirculation ratio and the composition of recirculation gas, so its NOx reduction efficiency is determined by them. In order to investigate the influence of factors which determine the reduction efficiency of NOx in MILD coal combustion, this study changed the flow rate and concentration of nitrogen (N2), carbon dioxide (CO2) and steam (H2O) which simulate the recirculation gas during the MILD coal combustion using our lab-scale drop tube furnace and performed the combustion experiment. As a result, its influence by the composition of recirculation gas was insignificant and it was shown that flue gas recirculation ratio influences the change of NOx concentration greatly. IMPLICATIONS: We investigated the influence of factors determining the nitrogen oxides (NOx) reduction efficiency in MILD coal combustion, which applied high-temperature flue gas recirculation. Using a lab-scale drop tube furnace and simulated recirculation gas, we conducted combustion testing changing the recirculation gas conditions. We found that the flue gas recirculation ratio influences the reduction of NOx emissions the most.

Joseon funerary texts tested using ancient DNA analysis of a Korean mummy.

In Korea, ancient DNA (aDNA) analysis has been applied to investigations into the genetic affiliations of mummies found in Joseon Dynasty tombs (1392-1910 CE), becoming now indispensable tool for researches studying human remains from archaeological sites. In the course of our recent examinations on a Korean mummy of Joseon Dynasty, we discovered many teeth contained in a pouch. And in fact, the historical literature on the topic of Joseon funerals contain general accounts of pouches in which an individual's lost teeth were collected over the course of a lifetime and, after death, placed in the coffin with the body. To test the veracity of the historical texts, the present study undertook aDNA analyses and compared the results between specifically questioned (Q) samples (teeth) and known (K) samples (brain and bone) from the mummy to ensure that they came from the same individual. Although the Q-K comparison of autosomal short tandem repeat results did not show full concordance due to allelic drop-outs in some loci, our statistical calculation indicated that the teeth in the pouch are highly likely those of the mummy. Additionally, Q-K comparison of mitochondrial DNA sequence results showed 100% matches between samples. There results, in short, could not gainsay the conjecture that the teeth samples originated from the person buried in the tomb; and if so, he must have kept his teeth for a long time after their loss. As the application of aDNA analysis to Korean mummy studies develops, there will be other opportunities to test historical documents, particularly those referring to funerary rites.

Low-nitrogen oxides combustion of dried sludge using a pilot-scale cyclone combustor with recirculation.

UNLABELLED: Recently, numerical and experimental studies have been conducted to develop a moderate or intense low-oxygen dilution (MILD) combustion technology for solid fuels. The study results demonstrated that intense recirculation inside the furnace by high-momentum air is a key parameter to achieve the MILD combustion of solid fuels. However, the high-velocity air requires a significant amount of electricity consumption. A cyclone-type MILD combustor was therefore designed and constructed in the authors' laboratory to improve the recirculation inside the combustor. The laboratory-scale tests yielded promising results for the MILD combustion of dried sewage sludge. To achieve pilot-scale MILD combustion of dried sludge in this study, the effects of geometric parameters such as the venturi tube configuration, the air injection location, and the air nozzle diameter were investigated. With the optimized geometric and operational conditions, the pilot-scale cyclone combustor demonstrated successful MILD combustion of dried sludge at a rate of 75 kg/hr with an excess air ratio of 1.05. IMPLICATIONS: A horizontal cyclone combustor with recirculation demonstrated moderate or intense low-oxygen dilution (MILD) combustion of dried sewage sludge at a rate of 75 kg/hr. Optimizing only geometric and operational conditions of the combustor reduced nitrogen oxide (NOx) emissions to less than 75 ppm. Because the operating cost of the MILD combustor is much lower than that of the selective catalytic reduction (SCR) applied to the conventional combustor, MILD combustion technology with the cyclone type furnace is an eligible option for reducing NOx emissions from the combustion of dried sewage sludge.

Strength of footing with punching shear preventers.

The punching shear failure often governs the strength of the footing-to-column connection. The punching shear failure is an undesirable failure mode, since it results in a brittle failure of the footing. In this study, a new method to increase the strength and ductility of the footing was proposed by inserting the punching shear preventers (PSPs) into the footing. The validation and effectiveness of PSP were verified through a series of experimental studies. The nonlinear finite element analysis was then performed to demonstrate the failure mechanism of the footing with PSPs in depth and to investigate the key parameters that affect the behavior of the footing with PSPs. Finally, the design recommendations for the footing with PSPs were suggested.

Absorption characteristics of new solvent based on a blend of AMP and 1,8-diamino-p-menthane for CO2 absorption.

Aqueous 1,8-diamino-p-menthane (KIER-C3) and commercially available amine solutions were tested for CO2 absorption. A 2-amino-2-methyl-1-propanol (AMP) solution with an addition of KIER-C3 showed 9.3% and 31.6% higher absorption rate for CO2 than the AMP solution with an addition of monoethanolamine (MEA) and ammonia (NH3), respectively. The reaction rate constant for CO2 absorption by the AMP/KIER-C3 solution was determined by the following equation: k2,AMP/C3 = 7.702 x 10(6) exp (-2248.03/T). A CO2 loading ratio of the AMP/KIER-C3 solution was also 2 and 3.4-times higher than that of the AMP/NH3 solution and the AMP/MEA solution, respectively. Based on the experimental results, KIER-C3 may be used as an excellent additive to increase CO2 absorption capability of AMP.

Heterogeneous mercury reaction chemistry on activated carbon.

Experimental and theory-based investigations have been carried out on the oxidation and adsorption mechanism of mercury (Hg) on brominated activated carbon (AC). Air containing parts per billion concentrations of Hg was passed over a packed-bed reactor with varying sorbent materials at 140 and 30 degrees C. Through X-ray photoelectron spectroscopy surface characterization studies it was found that Hg adsorption is primarily associated with bromine (Br) on the surface, but that it may be possible for surface-bound oxygen (O) to play a role in determining the stability of adsorbed Hg. In addition to surface characterization experiments, the interaction of Hg with brominated AC was studied using plane-wave density functional theory. Various configurations of hydrogen, O, Br, and Hg on the zigzag edge sites of graphene were investigated, and although Hg-Br complexes were found to be stable on the surface, the most stable configurations found were those with Hg adjacent to O. The Hg-carbon (C) bond length ranged from 2.26 to 2.34 A and is approximately 0.1 A shorter when O is a nearest-neighbor atom rather than a next-nearest neighbor, resulting in increased stability of the given configuration and overall tighter Hg-C binding. Through a density of states analysis, Hg was found to gain electron density in the six p-states after adsorption and was found to donate electron density from the five s-states, thereby leading to an oxidized surface-bound Hg complex.

Bench-scale studies of in-duct mercury capture using cupric chloride-impregnated carbons.

A brominated activated carbon (Darco Hg-LH) and cupric chloride-impregnated activated carbon (CuCl2-ACs) sorbent have been tested in a bench-scale entrained-flow reactor system which was developed for simulating in-flight mercury capture in ducts upstream of particulate matter control devices. The bench-scale experimental system has been operated with the conditions of a residence time of 0.75 s and a gas temperature of 140 degrees C to simulate typical conditions in the duct of coal-fired exhaust gas. In addition, sorbent deposition on walls which can occur in a laboratory-scale system more than in a full-scale system was significantly reduced so that additional mercury capture by the deposited sorbent was minimized. In the entrained-flow system, CuCl2-ACs demonstrated similar performance in Hg adsorption and better performance in Hg0 oxidation than Darco Hg-LH. In addition, the carbon content of those sorbents was found to determine their Hg adsorption capability in the entrained-flow system. The bench-scale entrained-flow system was able to demonstrate the important Hg adsorption and oxidation characteristics of the tested sorbents.

Performance of copper chloride-impregnated sorbents on mercury vapor control in an entrained-flow reactor system.

An entrained-flow system has been designed and constructed to simulate in-flight mercury (Hg) capture by sorbent injection in ducts of coal-fired utility plants. The test conditions of 1.2-sec residence time, 140 degrees C gas temperature, 6.7 m/sec (22 ft/sec) gas velocity, and 0-0.24 g/m3 (0-15 lbs of sorbent per 1 million actual cubic feet of flue gas [lb/MMacf]) sorbent injection rates were chosen to simulate conditions in the ducts. Four kinds of sorbents were used in this study. Darco Hg-LH served as a benchmark sorbent with which Hg control capability of other sorbents could be compared. Also, Darco-FGD was used as a representative raw activated carbon sorbent. Two different copper chloride-impregnated sorbents were developed in our laboratory and tested in the entrained-flow system to examine the possibility of using these sorbents at coal-fired power plants. The test results showed that one of the copper chloride sorbents has remarkable elemental mercury (Hg(o)) oxidation capability, and the other sorbent demonstrated a better performance in Hg removal than Darco Hg-LH.

Elevated soluble receptor activator of nuclear factor-kappaB ligand and reduced bone mineral density in patients with adolescent idiopathic scoliosis.

Generalized low bone mass and osteopenia in both axial and peripheral skeleton in adolescent idiopathic scoliosis (AIS) have been reported in literature. However, the exact mechanisms and causes of the bone loss in AIS are not identified yet. Therefore, this study examined the relationship between serum concentration of soluble receptor activator of nuclear factor-kappaB ligand (RANKL), serum level of osteoprotegerin (OPG) and bone mass in 72 patients with AIS and compared to those of 64 age- and gender-matched healthy controls. The mean lumbar spinal bone mineral density (LSBMD) and femoral neck BMD (FNBMD) in patients with AIS were decreased compared with that in control individuals, respectively (P = 0.0029 and P = 0.0192, respectively). The mean RANKL and RANKL to OPG ratio in patients with AIS were increased compared with that in control subjects, respectively (P = 0.0004 and P = 0.0032, respectively). The RANKL and RANKL to OPG ratios were negatively correlated to the LSBMD and serum OPG levels in both groups. Serum OPG levels were positively correlated to the LSBMD and FNBMD in both groups. These findings mean that the imbalance and the disturbed interaction of RANKL and OPG may be an important cause and pathogenesis in reduced BMD in AIS.

Steroid 9alpha-hydroxylation during testosterone degradation by resting rhodococcus equi cells.

The conversion pathway of testosterone to androst-4-ene-3,17-dione and 9alpha-hydroxy androstane metabolites, 9alpha-hydroxyandrost-4-ene-3,17-dione and 9alpha,17beta-dihydroxyandrost-4-en-3-one was proposed for the ring degradation in steroids by a minimal liquid medium (NMMP)-dispersed Rhodococcus equi ATCC 14887. The microorganism produced 9alpha-hydroxy androstane metabolites from testosterone at high conversion ratio without the addition of ring degradation inhibitory agents. Several NMMP-based media showed the similar effect on the microbial transformation, in which the respective molar yields of 9alpha-hydroxyandrost-4-ene-3,17-dione and 9alpha,17beta-dihydroxyandrost-4-en-3-one were approx. 3 to 47% and approx. 3 to 11%, respectively, whereas nutrient broth, a rich medium, basically showed no accumulation. On the basis of this evidence, magnesium sulfate and casamino acids among the components of NMMP were found to compromise the determinant for the production of the 9alpha-hydroxy androstane metabolites without appreciable decomposition of the steroid ring system.

Protein-kinase-C-mediated beta-catenin phosphorylation negatively regulates the Wnt/beta-catenin pathway.

Normally, the Wnt/beta-catenin pathway controls developmental processes and homeostasis, but abnormal activation of this pathway is a frequent event during the development of cancer. The key mechanism in regulation of the Wnt/beta-catenin pathway is the amino-terminal phosphorylation of beta-catenin, marking it for proteasomal degradation. Here we present small-molecule-based identification of protein kinase C (PKC)-mediated beta-catenin phosphorylation as a novel mechanism regulating the Wnt/beta-catenin pathway. We used a cell-based chemical screen to identify A23187, which inhibits the Wnt/beta-catenin pathway. PKC was activated by A23187 treatment and subsequently phosphorylated N-terminal serine (Ser) residues of beta-catenin, which promoted beta-catenin degradation. Moreover, the depletion of PKCalpha inhibited the phosphorylation and degradation of beta-catenin. Therefore, our findings suggest that the PKC pathway negatively regulates the beta-catenin level outside of the Wnt/beta-catenin pathway.

PCL microparticle-dispersed PLGA solution as a potential injectable urethral bulking agent.

The PCL microparticle-dispersed PLGA solutions were prepared as a potential injectable urethral bulking agent. The mixture solutions were prepared by mixing polycarprolactone (PCL) microparticles (diameter, 100 approximately 200mum; fabricated by a temperature-induced phase transition method) and poly(dl-lactic-co-glycolic acid) (PLGA) solution (dissolved in tetraglycol to 10wt%) with different PCL microparticle to PLGA solution ratio. The mixture solution was solidified by the precipitation of PLGA when the solution was contact with water. In contact with water, the PCL microparticles exhibited a well-packed structure entrapped in a solidified porous PLGA matrix, which can effectively prevent the microparticle migration in the body and retain its initial volume even after PLGA matrix degradation. The PCL microparticle-dispersed PLGA solution (particle to solution ratio, 45/55 (w/v)) was easily injected through 18G needle into back of hairless mouse (subcutaneously) and stably located at the apply site. The surrounding tissue including blood vessel were gradually infiltrated into the implant up to 8 weeks without the initial injected volume change and with little inflammatory response. The PCL microparticle-dispersed PLGA solution may be a good candidate as an injectable bulking agent for the treatment of urinary incontinence owing to its good injectability, volume retention potential as well as biocompatibility.

Inhibition of phorbol ester-induced COX-2 expression by epigallocatechin gallate in mouse skin and cultured human mammary epithelial cells.

Green tea polyphenols are reported to possess substantial antiinflammatory and chemopreventive properties. However, the molecular mechanism of chemopreventive activity of green tea polyphenols is not fully understood. An abnormally elevated level of cyclooxygenase-2 (COX-2) is implicated in the pathogenesis of carcinogenesis. In the present study, we found that pretreatment of the green tea extract enriched with catechin and epigallocatechin gallate (EGCG) by gavage inhibited COX-2 expression induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in mouse skin. Similarly, EGCG downregulated COX-2 in TPA-stimulated human mammary epithelial cells (MCF-10A) in culture. To further elucidate the underlying mechanism of COX-2 inhibition by green tea extract and EGCG, we examined their effects on the activation of extracellular signal-regulated protein kinase (ERK) and p38 mitogen-activated protein kinase (MAPK), which are upstream enzymes known to regulate COX-2 expression in many cell types. Pretreatment with EGCG as well as green tea extract caused a decrease in the activation of ERK. In addition, EGCG inhibited the catalytic activity of ERK and p38 MAPK, suggesting that these signal-transducing enzymes could be potential targets for previously reported antitumor promoting activity of EGCG.

Inhibition of 5alpha-reductase activity by diarylheptanoids from Alpinia officinarum.

The acetone extract from the rhizomes of Alpinia officinarum was evaluated for activity against 5alpha-reductase which had been prepared from rat prostate. The fraction responsible for the inhibition of the enzyme was purified, analyzed, and the active constituents were identified as four diarylheptanoids, 1,7-diphenylhept-4-en-3-one, dihydroyashabushiketol (1,7-diphenyl-5-hydroxy-3-heptanone), 5-hydroxy-7-(4"-hydroxy-3"-methoxyphenyl)-1-phenyl-3-heptanone and 5-hydroxy-7-(4"-hydroxyphenyl)-1-phenyl-3-heptanone.

Induction of apoptosis and caspase-3 activation by chemopreventive [6]-paradol and structurally related compounds in KB cells.

[6]-paradol, a pungent phenolic substance found in ginger and other Zingiberaceae plants, has been demonstrated to be an effective inhibitor of tumor promotion in mouse skin carcinogenesis. In the present study, we found that [6]-paradol and other structurally related derivatives, [10]-paradol, [3]-dehydroparadol, [6]-dehydroparadol, and [10]-dehydroparadol, with the exception of [3]-paradol induce apoptosis in an oral squamous carcinoma cell line, KB, in a dose-dependent manner. [10]-paradol and [10]-dehydroparadol exhibited a similar extent of cytotoxicity to that of [6]-paradol. [6]-Dehydroparadol and [3]-dehydroparadol appeared to be more potent, with an IC50 less than 40 microM. Treatment of KB cells with an apoptosis-inducing concentration of [6]-dehydroparadol caused induction of proteolytic cleavage of pro-caspase-3. These results suggest that [6]-paradol and structurally related derivatives induce apoptosis through a caspase-3-dependent mechanism.