Quantification of volatile fatty acids from cattle manure <i>via</i> non-catalytic esterification for odour indication

Lee, Sang-Ryong,Lee, Jechan,Cho, Seong-Heon,Kim, Jieun,Oh, Jeong-Ik,Tsang, Daniel C.W.,Jeong, Kwang-Hwa,Kwon, Eilhann E. Elsevier 2018 Science of the Total Environment Vol.610 No.-

<P><B>Abstract</B></P> <P>This report proposes a new approach to evaluate the odour nuisance of cattle manure samples from three different cattle breeds (<I>i.e.</I>, native cattle, beef cattle, and milk cow) by means of quantification and speciation of volatile fatty acids (VFAs). To this end, non-catalytic esterification thermally induced in the presence of a porous material (silica) was undertaken, and the optimal operational parameters such as the derivatizing temperature (330°C) for the maximum yield (≥99±0.4%) of volatile fatty acid methyl esters (VFAMEs) were established. Among the VFA species in cattle manure based on quantification of VFAs, the major species were acetic, butyric and valeric acid. Considering the odour threshold of each VFA, our experimental results suggested that the major contributors to odour nuisance were C<SUB>4–5</SUB> VFA species (<I>i.e.</I>, butyric and valeric acid). Hydrothermal treatment was performed at 150°C for 0–40min to correlate the formation of VFAs with different types of cattle feed formulations. Our experimental data demonstrated that the formation of total VFAs is linearly proportional to the hydrothermal treatment duration and the total content of VFAs in native cattle, beef cattle, and milk cow manure samples reached up to ~1000, ~3200, and ~2800ppm, respectively. Thus, this study demonstrated that the degree of VFA formation is highly dependent on cattle feed formulations, which rely significantly on the protein content. Furthermore, the hydrothermal treatment provides a favourable condition for generating more VFAs. In this context, producing cattle manure into refused derived fuel (RDF) <I>via</I> a hydrothermal treatment is not a viable option to control odour.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Volatile fatty acid measurement (VFAs) <I>via</I> the non-catalytic esterification </LI> <LI> Using volatile fatty acid as an odour indicator from cattle manure </LI> <LI> High conversion for volatile fatty acid methyl esters (>99%) from VFAs </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Controlling generation of benzenes and polycyclic aromatic hydrocarbons in thermolysis of polyvinyl chloride in CO₂

Lee, Taewoo,Oh, Jeong-Ik,Kim, Taejin,Tsang, Daniel C.W.,Kim, Ki-Hyun,Lee, Jechan,Kwon, Eilhann E. Pergamon 2018 Energy Conversion and Management Vol. No.

<P><B>Abstract</B></P> <P>This study emphasizes the control of benzene derivatives and polycyclic aromatic hydrocarbons (PAHs) in thermolysis of polyvinyl chloride (PVC) using CO<SUB>2</SUB>. To this end, the generation of benzenes and PAHs from the thermolysis of PVC in N<SUB>2</SUB> was characterized and all experimental findings from the thermolysis of PVC in N<SUB>2</SUB> were used as the reference value to configure the role of CO<SUB>2</SUB> in the thermolysis of PVC. The formation of hydrogen chloride (HCl) followed by the subsequent dechlorination in the thermolysis of PVC in N<SUB>2</SUB> resulted in the high yield of charring compounds, providing a favorable condition for forming benzene derivatives and PAHs. However, the thermal degradation of PVC in CO<SUB>2</SUB> showed the genuine thermal degradation patterns. For instance, despite the presence of the source for oxygen, the formation of CO at temperatures higher than 600 °C was observed in the thermolysis of PVC in CO<SUB>2</SUB>, suggesting that some unknown reactions between hydrocarbons from the thermolysis of PVC and CO<SUB>2</SUB> are initiated to form CO. In addition to these unknown reactions, the enhanced thermal cracking induced by CO<SUB>2</SUB> was observed. Two identified roles of CO<SUB>2</SUB> during the thermolysis of CO<SUB>2</SUB> was only limited at temperatures higher than 600 °C. However, despite no precise description for the mechanistic role of CO<SUB>2</SUB> at this stage of study, the formation of benzene derivatives and PAHs was effectively controlled in the presence of CO<SUB>2</SUB> at temperatures higher than 480 °C. Thus, these empirical findings in this study are necessary to further be investigated in the future, which offers a great venue offering a new means for modifying and/or controlling the harmful chemical species.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CO<SUB>2</SUB> acts a donor for carbon and oxygen. </LI> <LI> CO<SUB>2</SUB> expedites the thermal cracking of PVC. </LI> <LI> CO<SUB>2</SUB> block a pathway for the generation of benzene derivatives and PAHs. </LI> <LI> CO<SUB>2</SUB> can be used as reaction medium to control the harmful chemical species. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Bilateral Pedicle and Crossed Translaminar Screws in C2

Daniel Mendelsohn,Nicolas Dea,Robert Lee,Michael C. Boyd 대한척추외과학회 2015 Asian Spine Journal Vol.9 No.5

Multiple techniques exist for the fixation of C2, including axial pedicle screws and bilateral translaminar screws. We describe a novel method of incorporating both the translaminar and pedicle screws within C2 to improve fixation to the subaxial spine in patients requiring posterior cervical instrumentation for deformity correction or instability. We report three cases of patients with cervical spinal instability, who underwent cervical spine instrumentation for stabilization and/or deformity correction. Bilateral C2 pedicle screws were inserted, followed by bilateral crossed laminar screws. The instrumentation method successfully achieved fixation in all three patients. There were no immediate postoperative complications, and hardware positioning was satisfactory. Instrumenting C2 with translaminar and pedicle screws is technically feasible, and it may improve fixation to the subaxial spine in patients with poor bone quality or severe subaxial deformity, which require a stronger instrumentation construct.

Prediction of Micropollutant Elimination during Ozonation of Municipal Wastewater Effluents: Use of Kinetic and Water Specific Information

Lee, Yunho,Gerrity, Daniel,Lee, Minju,Bogeat, Angel Encinas,Salhi, Elisabeth,Gamage, Sujanie,Trenholm, Rebecca A.,Wert, Eric C.,Snyder, Shane A.,von Gunten, Urs American Chemical Society 2013 Environmental science & technology Vol.47 No.11

<P>Ozonation is effective in improving the quality of municipal wastewater effluents by eliminating organic micropollutants. Nevertheless, ozone process design is still limited by (i) the large number of structurally diverse micropollutants and (ii) the varying quality of wastewater matrices (especially dissolved organic matter). These issues were addressed by grouping 16 micropollutants according to their ozone and hydroxyl radical (<SUP>•</SUP>OH) rate constants and normalizing the applied ozone dose to the dissolved organic carbon concentration (i.e., g O<SUB>3</SUB>/g DOC). Consistent elimination of micropollutants was observed in 10 secondary municipal wastewater effluents spiked with 16 micropollutants (∼2 μg/L) in the absence of ozone demand exerted by nitrite. The elimination of ozone-refractory micropollutants was well predicted by measuring the <SUP>•</SUP>OH exposure by the decrease of the probe compound <I>p</I>-chlorobenzoic acid. The average molar <SUP>•</SUP>OH yields (moles of <SUP>•</SUP>OH produced per mole of ozone consumed) were 21 ± 3% for g O<SUB>3</SUB>/g DOC = 1.0, and the average rate constant for the reaction of <SUP>•</SUP>OH with effluent organic matter was (2.1 ± 0.6) × 10<SUP>4</SUP> (mg C/L)<SUP>−1</SUP> s<SUP>–1</SUP>. On the basis of these results, a DOC-normalized ozone dose, together with the rate constants for the reaction of the selected micropollutants with ozone and <SUP>•</SUP>OH, and the measurement of the <SUP>•</SUP>OH exposure are proposed as key parameters for the prediction of the elimination efficiency of micropollutants during ozonation of municipal wastewater effluents with varying water quality.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2013/esthag.2013.47.issue-11/es400781r/production/images/medium/es-2013-00781r_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/es400781r'>ACS Electronic Supporting Info</A></P>

Effects of calcium carbonate on pyrolysis of sewage sludge

Kwon, Eilhann E.,Lee, Taewoo,Ok, Yong Sik,Tsang, Daniel C.W.,Park, Chanhyuk,Lee, Jechan Elsevier 2018 ENERGY Vol.153 No.-

<P><B>Abstract</B></P> <P>This study demonstrates that calcium carbonate (CaCO<SUB>3</SUB>) allows not only enhancement of the production of CO as syngas, but also reduction of the content of polycyclic aromatic hydrocarbons (PAHs) in the pyrolytic products from sewage sludge. CO<SUB>2</SUB> was formed by the decomposition of CaCO<SUB>3</SUB> in pyrolysis. The CO<SUB>2</SUB> derived from CaCO<SUB>3</SUB> enhanced thermal cracking of volatile organic carbons (VOCs) generated during the pyrolysis of sewage sludge and provided an additional source of C and O, likely enhancing the production of CO at >650 °C. In addition, more solid product was converted into gaseous and liquid products by the addition of CaCO<SUB>3</SUB> in the pyrolysis of sewage sludge. This work suggests that CaCO<SUB>3</SUB> can be used as an inexpensive source of CO<SUB>2</SUB> that increases thermal efficiency of the pyrolysis process and reduces the evolution of harmful chemical species such as PAHs during thermal treatment of the byproduct during processing at municipal and industrial wastewater treatment facilities (<I>i.e.</I>, sewage sludge).</P> <P><B>Highlights</B></P> <P> <UL> <LI> CaCO<SUB>3</SUB> is used as an additive to pyrolysis feedstock to enhance energy recovery. </LI> <LI> Addition of CaCO<SUB>3</SUB> to sewage sludge decreases the content of PAHs in pyrolytic product. </LI> <LI> CaCO<SUB>3</SUB> helps yield more gaseous and liquid pyrolytic products in pyrolysis of sewage sludge. </LI> </UL> </P>

Biodiesel synthesis using chicken manure biochar and waste cooking oil

Jung, Jong-Min,Lee, Sang-Ryong,Lee, Jechan,Lee, Taewoo,Tsang, Daniel C.W.,Kwon, Eilhann E. Elsevier Applied Science 2017 Bioresource technology Vol.244 No.1

<P><B>Abstract</B></P> <P>This study laid an emphasis on the possible employment of biochar generated from pyrolysis of chicken manure to establish a green platform for producing biodiesel. To this end, the pseudo-catalytic transesterification reaction using chicken manure biochar and waste cooking oil was investigated. Compared with a commercial porous material (SiO<SUB>2</SUB>), chicken manure biochar generated from 350°C showed better performance, resulting in 95.6% of the FAME yield at 350°C. The Ca species in chicken manure biochar imparted strong catalytic capability by providing the basicity for transesterification. The identified catalytic effect also led to the thermal cracking of unsaturated FAMEs, which decreased the overall FAME yield. For example, 40–60% of converted FAMEs were thermally degraded. To avoid undesirable thermal cracking arising from the high content of the Ca species in chicken manure biochar, the fabrication of chicken manure biochar at temperatures ≥350°C was highly recommended.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Biodiesel synthesis using chicken manure biochar. </LI> <LI> Establish a green platform for producing biodiesel using chicken manure biochar. </LI> <LI> Enhanced yield of biodiesel using chicken manure biochar due to strong catalytic capability. </LI> <LI> 95.6% of the FAME yield using chicken manure biochar generated from 350°C. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Pyrochlore chemistry from the Sokli phoscorite-carbonatite complex, Finland: Implications for the genesis of phoscorite and carbonatite association

Jung Lee, Mi,Ik Lee, Jong,Garcia, Daniel,Moutte, Jaques,Terry Williams, C.,Wall, Frances,Kim, Yeadong Geochemical Society of Japan] 2006 Geochemical journal Vol.40 No.1

<P>The phoscorite-carbonatite complex in the Sokli alkaline-carbonatite massif, northern Finland, comprises five stages of intrusions of phoscorites and carbonatites (P1-C1, P2-C2 and P3-C3 for phoscorites and calcite carbonatites;D4 and D5 for dolomite carbonatites). The phoscorites and calcite carbonatites at Sokli usually occur as pairs with the same mineral assemblages. Pyrochlore is found in the majority of rock types in the Sokli phoscorite-carbonatite complex, shows wide compositional variation and seems to preserve evolution trends of host rocks. Crystallization of pyrochlore begins from the P2-C2 phoscorite and calcite carbonatite and continues up to the latest D5 dolomite carbonatite. Pyrochlore in the early stage P2-C2 rocks has high U and Ta contents. These elements suddenly decrease from the P3-C3 rocks, on the other hand, Th and Ce contents increase. The compositions of the late generations from the D4 and D5 rocks are close to that of an ideal end-member pyrochlore with formula <TEX>$(Ca,Na)_2Nb_2O_6$</TEX> F. The Nb/Ta ratio and F content of pyrochlore increase from P2-C2 to the latest D5 dolomite carbonatite. The composition and evolutionary history of pyrochlore from the phoscorites are distinguished from those of the associated calcite carbonatites. Pyrochlore from the calcite carbonatites shows larger A-cation deficiencies compared to those from the paired phoscorites. Ta and Zr contents are slightly higher in pyrochlore from the calcite carbonatites, whereas Ti is generally higher in pyrochlore from the associated phoscorites. Moreover, pyrochlore from the phoscorites always shows a longer and more complex crystallization history compared to that of the same stage carbonatites. This indicates that the chemical condition was clearly different in the two systems during the crystallization of pyrochlore. Based on these results, together with the previous mineralogical and geochemical studies on the Sokli phoscorite-carbonatite complex, we propose a liquid immiscibility process as the most possible seg-regation mechanism of the two associated rocks. The composition of pyrochlore in the late dolomite carbonatites is dis-tinct and always lies on the evolutional trend of the earlier varieties. This implies that the dolomite carbonatites are the final magmatic products of the Sokli phoscorite-carbonatite system.</P>

Carbon dioxide assisted thermal decomposition of cattle excreta

Lee, Sang-Ryong,Lee, Jechan,Lee, Taewoo,Cho, Seong-Heon,Oh, Jeong-Ik,Kim, Hana,Tsang, Daniel C.W.,Kwon, Eilhann E. Elsevier BV 2018 Science of the Total Environment Vol.615 No.-

<P><B>Abstract</B></P> <P>To develop the environmentally benign thermo-chemical process, this study placed great emphasis on the influence of CO<SUB>2</SUB> on pyrolysis of cattle excreta for energy recovery. To this end, this study evaluates the possible enhanced energy recovery from cattle excreta using CO<SUB>2</SUB> as reaction medium/feedstock in the thermal degradation of cattle excreta. The enhanced generation of CO in the presence of CO<SUB>2</SUB> reached up to 15.15mol% (reference value: 0.369mol%) at 690°C, which was equivalent to ~4000 times more generation of CO. In addition to the enhanced generation of CO, the enhanced generation of H<SUB>2</SUB> and CH<SUB>4</SUB> in the thermal degradation of cattle excreta in CO<SUB>2</SUB>. Thus, the findings of this study revealed two genuine roles of CO<SUB>2</SUB>: 1) enhanced thermal cracking of volatile organic carbons (VOCs) evolved from the thermal degradation of cattle excreta and 2) direct reaction between VOCs and CO<SUB>2</SUB> via gas phase reaction.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Use of animal manure as an energy source </LI> <LI> No additional energy input for mitigating pyrolytic oil </LI> <LI> Enhanced generation of pyrolytic gases in the thermal degradation of cattle excreta </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Worst Average Queueing Delay of Multiple Leaky-Bucket-Regulated Streams and Jumping-Window Regulated Stream

Lee, Daniel C. The Korea Institute of Information and Commucation 2004 Journal of communications and networks Vol.6 No.1

This paper presents deterministic, worst-case analysis of a queueing system whose multiple homogeneous input streams are regulated by the associated leaky buckets and the queueing system that has a single stream regulated by the jumping-window. Queueing delay averaged over all items is used for performance measure, and the worst-case input traffic and the worst-case performance are identified for both queueing systems. For the former queueing system, the analysis explores different phase relations among leaky-bucket token generations. This paper observes how the phase differences among the leaky buckets affect the worst-case queueing performance. Then, this paper relates the worst-case performance of the former queueing system with that of the latter (the single stream case, as in the aggregate streams from many users, whose item arrivals are regulated by one jumping-window). It is shown that the worst-case performance of the latter is identical to that of the former in which all leaky buckets have the same phase and have particular leaky bucket parameters.

Worst Closed-Loop Controlled Bulk Distributions of Stochastic Arrival Processes for Queue Performance

Lee Daniel C. The Korea Institute of Information and Commucation 2005 Journal of communications and networks Vol.7 No.1

This paper presents basic queueing analysis contributing to teletraffc theory, with commonly accessible mathematical tools. This paper studies queueing systems with bulk arrivals. It is assumed that the number of arrivals and the expected number of arrivals in each bulk are bounded by some constraints B and (equation omitted), respectively. Subject to these constraints, convexity argument is used to show that the bulk-size probability distribution that results in the worst mean queue performance is an extremal distribution with support {1, B} and mean equal to A. Furthermore, from the viewpoint of security against denial-of-service attacks, this distribution remains the worst even if an adversary were allowed to choose the bulk-size distribution at each arrival instant as a function of past queue lengths; that is, the adversary can produce as bad queueing performance with an open-loop strategy as with any closed-loop strategy. These results are proven for an arbitrary arrival process with bulk arrivals and a general service model.