Microwavepyrolysis, a Way to Recycle Metals and Produce Oil and Syngas

( Christer Forsgren ),( Jonas Christéen ) 한국폐기물자원순환학회 2023 I-CIPEC Vol.2012 No.0

그리스도의 능동적 순종의 전가에 대한 논쟁

유창형 칼빈대학교 2019 칼빈論壇 Vol.- No.39

Late Holocene glacial advance and ice shelf growth in Barilari Bay, Graham Land, west Antarctic Peninsula

Christ, Andrew J.,Talaia-Murray, Manique,Elking, Natalie,Domack, Eugene W.,Leventer, Amy,Lavoie, Caroline,Brachfeld, Stefanie,Yoo, Kyu-Cheul,Gilbert, Robert,Jeong, Sun-Mi,Petrushak, Stephen,Wellner, J Geological Society of America 2015 Geological Society of America bulletin Vol.127 No.1

<P>Three marine sediment cores were collected along the length of the fjord axis of Barilari Bay, Graham Land, west Antarctic Peninsula (65°55′S, 64°43′W). Multi-proxy analytical results constrained by high-resolution geochronological methods (<SUP>210</SUP>Pb, radiocarbon, <SUP>137</SUP>Cs) in concert with historical observations capture a record of Holocene paleoenvironmental variability. Our results suggest early and middle Holocene (>7022–2815 cal. [calibrated] yr B.P.) retreated glacial positions and seasonally open marine conditions with increased primary productivity. Climatic cooling increased sea ice coverage and decreased primary productivity during the Neoglacial (2815 to cal. 730 cal. yr B.P.). This climatic cooling culminated with glacial advance to maximum Holocene positions and expansion of a fjord-wide ice shelf during the Little Ice Age (LIA) (ca. 730–82 cal. yr B.P.). Seasonally open marine conditions were achieved and remnant ice shelves decayed within the context of recent rapid regional warming (82 cal. yr B.P. to present). Our findings agree with previously observed late Holocene cooling and glacial advance across the Antarctic Peninsula, suggesting that the LIA was a regionally significant event with few disparities in timing and magnitude. Comparison of the LIA Antarctic Peninsula record to the rest of the Southern Hemisphere demonstrates close synchronicity in the southeast Pacific and southern most Atlantic region but less coherence for the southwest Pacific and Indian Oceans. Comparisons with the Northern Hemisphere demonstrate that the LIA Antarctic Peninsula record was contemporaneous with pre-LIA cooling and sea ice expansion in the North Atlantic–Arctic, suggesting a global reach for these events.</P>

Why Do Trade Negotiations Take So Long?

( Christ Oph Moser ),( Andrew K Rose ) 세종대학교 경제통합연구소 2012 Journal of Economic Integration Vol.27 No.2

The Doha multilateral round of trade negotiations sponsored by the WTO has been dragging on for over a decade, with no end in sight. In this short paper we assess empirically what determines the duration of trade negotiations, focusing on the span between the start of trade talks and their conclusion. We use data from 88 regional trade agreements between 1988 and 2009, and a semi-parametric Cox proportional hazards model. Four factors are robust determinants of the length of RTA negotiations. Negotiations are more protracted when there are more countries at the negotiation table, and when the countries are not from the same region. Negotiations between more open and richer countries also finish more quickly.

Shear Strength of Frozen Sand

Martin Christ,Young-Chin Kim,Jun-Boum Park 한국지반환경공학회 2009 한국지반환경공학회 학술발표회논문집 Vol.2009 No.-

Antimicrobial activity of tea tree oil nanoparticles against American and European foulbrood diseases agents

Roberto Christ Vianna Santos,Leonardo Quintana Soares Lopes,Camilla Filippi dos Santos Alves,Viviane Pedroso Fausto,Kauana Pizzutti,Victor Barboza,Marcia Ebling de Souza,Renata Platchek Raffin,Patrici 한국응용곤충학회 2014 Journal of Asia-Pacific Entomology Vol.17 No.3

Paenibacillus larvae and Melissococcus plutonius are the primary bacterial pathogens of honeybees and the causativeagents of American and European foulbrood disease (AFB and EFB) respectively. Such diseases have beengaining importance since there are few therapeutic options beyond the reporting of microorganisms resistantto conventional antibiotics. Due to the inefficiency and/or lowefficacy of some antibiotics, researches with nanotechnologyrepresent, possibly, new therapeutic strategies. Nanostructured drugs have presented some advantagesover the conventional medicines, such as slow, gradual and controlled release, increased bioavailability,and reduced side-effects, among others. In this study, in vitro antimicrobial activity of tea tree oil (TTO) nanoparticlesagainst Paenibacillus species, including P. larvae and M. plutonius strains was evaluated. Minimal inhibitoryconcentration (MIC) in Mueller–Hinton or KSBHI broth by the microdilution method was assessed. TTO registeredMIC values of 0.18–6.25%, while the MIC values obtained for the TTO nanoparticle were of 0.01–0.93%. The possible toxic effect of TTO and TTO nanoparticle has been assessed by the spraying application method inthe concentrations higher than the MICs. Bee mortality was evident only in treatment with TTO and the TTOnanoparticles show no toxic effects after 7 days of observation. Our results showed for the first time that TTOnanoencapsulation presented a high activity against Paenibacillus species and M. plutonius strains showing thatthe use of nanotechnology may represent one alternative way for the treatment or prevention of AFB and EFB.

Experimental Study on the Physical-Mechanical Properties of Frozen Silt

Martin Christ,김영진 대한토목학회 2009 KSCE JOURNAL OF CIVIL ENGINEERING Vol.13 No.5

The objective of this study was to investigate the physical-mechanical characteristics of frozen Siberian silt. Unfrozen water content, uniaxial compressive strength and direct-tensile strength of frozen silt samples at different moisture contents were determined in the laboratory. Experimental results revealed that the amount of unfrozen water in the silt decreased with descending temperature and stabilized at temperatures below -10˚C. Even at very low temperatures a considerable amount of unfrozen water remained. Mechanical strength test results showed a strong dependence of the stress-strain behavior of the frozen silt on the moisture content and temperature. The strength for compression and tension increased with decreasing temperature and increasing moisture content. At any given temperature and moisture content compressive strength was significantly greater than tensile strength. Based on the compressive and tensile stress-strain relationship at a given temperature and moisture content, approximate values of strength ratio, failure strain ratio and deformation modulus ratio were established. The objective of this study was to investigate the physical-mechanical characteristics of frozen Siberian silt. Unfrozen water content, uniaxial compressive strength and direct-tensile strength of frozen silt samples at different moisture contents were determined in the laboratory. Experimental results revealed that the amount of unfrozen water in the silt decreased with descending temperature and stabilized at temperatures below -10˚C. Even at very low temperatures a considerable amount of unfrozen water remained. Mechanical strength test results showed a strong dependence of the stress-strain behavior of the frozen silt on the moisture content and temperature. The strength for compression and tension increased with decreasing temperature and increasing moisture content. At any given temperature and moisture content compressive strength was significantly greater than tensile strength. Based on the compressive and tensile stress-strain relationship at a given temperature and moisture content, approximate values of strength ratio, failure strain ratio and deformation modulus ratio were established.

The Influence of Temperature and Cycles on Acoustic and Mechanical Properties of Frozen Soils

Martin Christ,김영진,박준범 대한토목학회 2009 KSCE JOURNAL OF CIVIL ENGINEERING Vol.13 No.3

The influence of temperature and Freeze-Thaw (FT) processes on the mechanical properties of frozen soils were investigated in the laboratory in order to give a better understanding of changes in engineering properties of frozen soils. The experimental data revealed a dependence of compressional and shear wave velocity of frozen soils on temperature, soil type and FT cycles. Compressional wave velocity showed a strong correlation to the unfrozen water content dependent on soil type, while shear wave velocity was mainly influenced by the ice content and the soil matrix. Compressional and shear wave velocity changed for samples subject to FT cycling, which appears to be caused by alterations in the soil structure. Elastic constants were calculated based on the wave propagation theory and compared to results from uniaxial compression tests. The dynamic elastic modulus, dynamic shear modulus and compressive strength increased with descending temperature. FT cycles reduced the compressive strength, and influenced the dynamic elastic constants. Poisson’s ratios of all tested soils not subject to FT cycling decreased upon a change in negative temperature; while the opposite trend was observed for soils influenced by FT cycles. The influence of temperature and Freeze-Thaw (FT) processes on the mechanical properties of frozen soils were investigated in the laboratory in order to give a better understanding of changes in engineering properties of frozen soils. The experimental data revealed a dependence of compressional and shear wave velocity of frozen soils on temperature, soil type and FT cycles. Compressional wave velocity showed a strong correlation to the unfrozen water content dependent on soil type, while shear wave velocity was mainly influenced by the ice content and the soil matrix. Compressional and shear wave velocity changed for samples subject to FT cycling, which appears to be caused by alterations in the soil structure. Elastic constants were calculated based on the wave propagation theory and compared to results from uniaxial compression tests. The dynamic elastic modulus, dynamic shear modulus and compressive strength increased with descending temperature. FT cycles reduced the compressive strength, and influenced the dynamic elastic constants. Poisson’s ratios of all tested soils not subject to FT cycling decreased upon a change in negative temperature; while the opposite trend was observed for soils influenced by FT cycles.

The Effect of Freeze-Thaw Cycles on the Mechanical Properties of Frozen Subgrade Soil

크리스트 마틴(Christ Martin),김영진(Kim Young-Chin) 대한토목학회 2008 대한토목학회 학술대회 Vol.2008 No.10

Bioactive Compound Produced by Endophytic Fungi Isolated From Pelargonium sidoides Against Selected Bacteria of Clinical Importance

( Madira Coutlyne Manganyi ),( Christ-donald K. Tchatchouang ),( Thierry Regnier ),( Cornelius Carlos Bezuidenhout ),( Collins Njie Ateba ) 한국균학회 2019 Mycobiology Vol.47 No.3

Endophytic fungi have the ability to live inside the host plant tissues without causing neither symptoms of diseases/or harm. Opportunistic infections are accountable for majority of the outbreaks, thereby putting a burden on the health system. To investigate and characterize the bioactive compounds for the control of bacteria of clinical importance, extracts from endophytic fungi were isolated from indigenous South African medicinal plants. Extracts from endophytic fungi were isolated from 133 fungal strains and screened against Gram positive and negative bacteria namely Bacillus cereus, Escherichia coli, Enterococcus faecium, and E. gallinarum using disk diffusion. Furthermore, gas chromatography-mass spectrometry was performed to identify the bioactive compounds. Sixteen out of one hundred and thirtythree (12%) fungi extracts exhibited antibacterial properties against some of the selected bacteria. E. coli was found to be the most susceptible in contrast to E. faecium and E. gallinarum which were the most resistant. The isolate MHE 68, identified as Alternaria sp. displayed the greater spectrum of antibacterial activities by controlling selected clinical bacteria strains including resistant E. faecium and E. gallinarum. The chemical analysis of the extract from MHE 68 indicated that linoleic acid (9,12-octadecadienoic acid (Z,Z)) and cyclodecasiloxane could be accountable for the antibacterial activity. This is the first study conducted on the secondary metabolites produced by endophytic fungal strains isolated from the Pelargonium sidoides DC. possessing antibacterial properties.