DATE: Sunday, October 20, 2019
TIME: 12:00 PM - 03:00 PM
LOCATION:Building 1, Level 3, Room 3119
Abstract: The horizontal resolution is a prominent constraint on the accuracy of simulating synoptic and sub-synoptic scale rainfall. High resolution General Circulation Models are significantly better than Regional Climate Models and conventional coarse resolution General Circulation Models in their representation of atmospheric circulation and precipitation. In this study two monsoon systems over Africa, the features associated with them, and their future are examined using a high resolution Atmospheric General Circulation Model, HiRAM. HiRAM, which is developed at Geophysical Fluid Dynamics Laboratory, employs a cubed-sphere finite volume dynamical core and uses shallow convective scheme for moist convection and stratiform cloudiness instead of a deep convective parameterization. Future projections are conducted using the representative concentration pathway, RCP 8.5 from 2076 to 2099 at C360 (~25 km) resolution. The study explores three important climate features of the region: West African Monsoon, Southern African Monsoon, and African Easterly Waves. These climate systems particularly benefit from high resolution simulations since they involve several multiscale processes and are influenced by coastlines and complex topography. Particular attention is given to Southern African monsoon since it is vastly underexplored. The study shows that, in the RCP 8.5 scenario, elevated areas of Sahel and western Sahara experience robust warming of >4K by the end of the 21st century. Precipitation increases over the equatorial Atlantic and the Guinean coast, while the southern Sahel appears drier. The wave activity of the region also shows a significant increase. The examination of the future projections of southern Africa reveals increased precipitation over central Africa and contrasting anomalies over northern Madagascar while Kalahari desert experience significant warming. The rainfall change in a global warming scenario is not unidirectional, unlike the temperature which increases almost everywhere and this emphasizes the need for more projection studies.
TIME: 04:00 PM - 06:00 PM
LOCATION:Al-Kindi Building (Bldg. 5), Room 5209
ABSTRACT: Ligand-protected metal nanoclusters (NCs), which are ultra-small nanoparticles marked by their atomic precision, are distinctly importance for contemporary nanomaterials. NCs have attracted significant research attention for utilizing their novel optical and physicochemical properties in various applications, including fluorescence sensing, catalysis, and biomedical applications. This dissertation deals with ligand-protected atomically precise silver NCs and is divided into two main parts. The first part is focused on the exploration and design of well-defined silver NCs through surface co-ligand engineering. The second part is related to the development of silver NC-based frameworks (NCFs). In the first part, we designed a synthetic strategy based on engineering the structure of the phosphine co-ligands with thiols to generate the large box-shaped [Ag67(SPhMe2)32(PPh3)8]3+ (referred to as Ag67) NC. The strategy demonstrates that the combined use of judiciously chosen thiol and phosphine co-ligands can result in stable highly anisotropic box-like shapes. The optical absorption spectrum of the Ag67 NC displays highly structured multiple sharp peaks. The crystal structure shows a Ag23 core formed of a centered cuboctahedron (an unprecedented core geometry in silver clusters), which is encased by a layer with a composition of Ag44S32P8 arranged in the shape of a box. The electronic structure of this box-shaped cluster resembles a jellium box model with 32 free electrons. In the second part, a novel approach is developed for the assembly and linkage of atomically precise Ag NCs into one-dimensional (1D) and two-dimensional (2D) NC-based frameworks (NCFs) with atomic-level control over cluster size and dimensionality. With this approach three novel, but related, crystal structures (one silver NC and two NCFs) were synthesized. These structures have the same protecting ligands, and also the same organic linker. The three structures exhibit a similar square gyrobicupola geometry of the building NC unit with only a single Ag atom difference. The critical role of using a chloride template in controlling the NC's nuclearity was demonstrated, as well as the effect of a single Ag atom difference in the NC's size on the NCF's dimensionality, optical properties, and thermal stability.
DATE: Monday, October 21, 2019
TIME: 12:00 PM - 01:00 PM
LOCATION:Auditorium Between Buildings 4 & 5
Abstract: We have designed and synthesized various artificial supramolecular systems, which show highly cooperative molecular functions. First, we have synthesized pseudomacrocycles and pseudomacrobicycles, whose frameworks are maintained by coordination bonding.1 A tripodal compound bearing a bipyridine unit at the end of each chain reacted with Fe(II) as an effector to give the corresponding bicyclic metallohost, pseudocryptand. The unique helical molecules exhibited positive and negative allosteric effects on ion recognition for ceasium and sodium, respectively. In addition, this helical structural motif can be used as a building block for the construction of more sophisticated self-assembled molecular architectures based on a hierarchical strategy.2
Next, we introduce novel derivatives of salamo (1,2-bis(salicylideneaminooxy)ethane), saloph and salen ligands.1 One of the characteristic properties of the salamo derivatives is very low reactivity toward disproportionation. Thus, not only a macrocyclic trisalamo ligand but also acyclic oligosalamo derivatives were isolated as a stable species. The acyclic bissalomo ligands exhibited very cooperative complexation ability toward Zn(II) to give C-shaped helical homotrinuclear Zn complexes, which can be quantitatively converted to heterotrinuclear Zn2•M (M=La, Ca, etc.) complexes. The calcium selectivity of the transmetalation among alkali and alkaline metal ions is extremely high. The helical sense of C-shaped multi-nuclear salamo complexes was successfully controlled by external stimuli, and we also created a multi-step-helicity-switching system by using different metal ions for the complexation of a chiral salamo derivative.3 Other metallo-supramolecular salamo and saloph systems will also be discussed.4-7
Dipyrrin complexes, especially the boron complexes, BODIPYs, have been used as a sensor, a bioimaging tool, etc. because they exhibit excellent photophysical properties and photostability. However, applications of the BODIPY derivatives and analogs to functional host molecules that utilize a B-F unit as a binding site are interesting and important but had never been reported. Thus, we synthesized macrocyclic8,9 and linear10 BODIPY oligomers as a unique host molecule, in which the BODIPY units work as an emissive unit and a binding site for a guest through a new type of B-F•••cation interactions. Uv-vis and fluorescence spectra of the cyclic and linear BODIPY derivatives were changed in the presence of a cationic guest. A macrocyclic BODIPY trimer bearing m-phenylene spacers exhibits high recognition ability to secondary ammonium salts, especially to protonated adrenaline through noncovalent interactions including CH- interactions and hydrogen bonds between the B-F and the ammonium protons.9References Nabeshima, T., Synergy in Supramolecular Chemistry: Nabeshima, T., Ed.; CRC Press: New York, 2015, pp 1-19. Nakamura, T.; Kimura, H.; Okuhara, T.; Yamamura, M.; Nabeshima, T. J. Am. Chem. Soc. 2016, 138, 794–797. Akine, S.; Sairenji, S.; Taniguchi, T.; Nabeshima, T. J. Am. Chem. Soc. 2013, 135, 12948-12951. Akine, S.; Matsumoto, T.; Nabeshima, T. Angew. Chem. Int. Ed. 2016, 55, 960-964. Nakamura, T.; Kaneko, Y.; Nishibori, E.; Nabeshima, T. Nature Commun., 2017, 8, 129. Sairenji, S.; Akine, S.; Nabeshima, T. Sci. Rep. 2018, 8, 137.  Nakamura, T.; Tsukuda, S.; Nabeshima, T. J. Am. Chem. Soc. 2019, 141, 6462-6467. Sakamoto, N.; Ikeda, C.; Nabeshima, T. Chem. Commun., 2010, 46, 6732-6734. Nakamura, T.; Yamaguchi, G.; Nabeshima, T. Angew. Chem. Int. Ed., 2016, 55, 9606-9609. Sakamoto, N.; Ikeda, C.; Yamamura, M.; Nabeshima, T. Chem. Commun., 2012, 48, 4818-4820.
DATE: Tuesday, October 22, 2019
TIME: 03:00 PM - 04:00 PM
LOCATION:Ibn Al Haytham Building , Bldg 2, Level 5, Room 5220
DATE: Wednesday, October 23, 2019
TIME: 10:00 AM - 11:00 AM
LOCATION:Al Kindi Building, Bldg 5, Level 5, Room 5209
Abstract: Photocatalytic water splitting using solar irradiation has the potential to produce sustainable hydrogen fuel on a large scale. Practical solar energy conversion requires the development of new, stable photocatalysts that operate efficiently under a broad range of visible wavelengths. Organic semiconductors are increasingly being employed as photocatalysts due to their earth abundance, aqueous stability, and optical absorptions that can be tuned to the solar spectrum. However, much remains unknown about the mechanism of organic semiconductor photocatalysis, and significant efficiency improvements need to be made before organic photocatalysts can achieve practical solar energy conversion.
In chapter 2 the effect of residual Pd on hydrogen evolution activity in conjugated polymer photocatalysts was systematically investigated using colloidal poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) nanoparticles (NPs). Residual Pd, originating from the synthesis of F8BT via Pd catalysed polycondensation polymerisation, was observed in the form of homogenously distributed Pd NPs within the polymer. Residual Pd was essential for any hydrogen evolution to be observed from this polymer, and very low Pd concentrations (<40 ppm) were sufficient to have a significant effect on the hydrogen evolution reaction (HER) rate. The HER rate increased linearly with increasing Pd concentration from <1 ppm to approximately 100 ppm, at which point the rate began to saturate. Transient absorption spectroscopy experiments support these conclusions and suggest that residual Pd mediates electron transfer from the F8BT NPs to protons in the aqueous phase.
Photocatalysts formed from a single organic semiconductor typically suffer from inefficient intrinsic charge generation, which leads to low photocatalytic activities. In chapter 3 we demonstrate that incorporating a heterojunction between a donor polymer and non-fullerene acceptor in organic NPs can result in hydrogen evolution photocatalysts with greatly enhanced photocatalytic activity. Control of the nanomorphology of these NPs was achieved by varying the stabilizing surfactant employed during NP fabrication, converting it from a core-shell structure to an intermixed donor/acceptor blend, and increasing H2 evolution by an order of magnitude. The resulting photocatalysts display an unprecedentedly high H2 evolution rate of over 60,000 µmolh-1g-1 under 350 to 800 nm illumination and external quantum efficiencies over 6% in the region of maximum solar photon flux.
LOCATION:Auditorium between B4 and B5, Room 0215
Pre-ignition is one of the oldest problems plaguing internal combustion engines. As the name implies, through some mysterious mechanism, a flame initiates in the fuel-air mixture BEFORE the spark plug fires! This confounding issue has resurfaced recently with an increase in the production of turbocharged engines aimed at reducing CO2 emission from spark-ignited engines. Stochastic Pre-ignition, as it is known, occurs rarely and randomly, once in 2,000 to 20,000 cycles at high loads. With random events occurring so rarely, long tedious run times are required to capture an event. With such a rare occurrence of stochastic pre-ignition, one might think the rare nuisance event can be ignored. Not so, as a flame occurring well before spark ignition leads to very high pressures at top dead center. A single event can cause permanent hardware damage to the engine.
This dissertation looks at Pre-ignition from various aspects: detecting Pre-ignition via in-house ion-current sensors, investigating evasive strategies avoiding engine damage, suggesting methods suppressing Pre-ignition frequency, and understanding the phenomenon behind such stochastic behavior. Several methods suppressing Pre-ignition include injecting fuel in multiple pulses, using Octane-on-Demand Concept, using Gasoline and Methane in a dual fuel concept, injecting various fluids like Gasoline, Ethanol, Methanol, and Water in the late compression stroke and injecting water in intake, compression, and late exhaust stroke.
The dissertation also provides a conceptual framework for Pre-ignition occurrence. The framework proposes that a successful pre-ignition event occurrence is reliant on the success of several steps: In Step 1, Pre-ignition precursors (deposits flakes or rogue oil-fuel droplets) are formed and heated during the power stroke. Normally these embers are swept out in the exhaust stroke. But occasionally, an ember may be trapped in the residual gas that remains after the exhaust stroke (Step 2). These embers can ignite a flame in the fresh intake charge before the spark plug fires (Step 3). The probability of step 1 is dependent on the mixture formation, the probability of step 2 is dependent on the scavenging process, and the probability of step 3 depends on in-cylinder temperature and pressure as top dead center is approached.
Eshan Singh joined KAUST in Fall 2015. Before that, he was a Trainee Scientist at National Laboratory CSIR-Indian Institute of Petroleum, where he also received his master's degree in Advanced Automotive Technology in 2014. Eshan has authored 20 peer-reviewed publications, a book chapter, and holds one patent on detection followed by evasive measures to defuse pre-ignition. He has also represented KAUST at several prestigious International Conferences.
TIME: 01:30 PM - 03:30 PM
ABSTRACT: As one of the most promising solar cell technologies,
organic solar cells have unique superiorities distinct from inorganic
counterparts, such as semitransparency, flexibility and
solution-processability, as well as tunable photophysical properties, which
originate from the structural verstailities of organic semiconductors. A major
breakthrough in OSCs was the exploration of novel non-fullerene electron
acceptor (NFAs): In comparison with traditional fullerene derivative acceptors,
NFA possess several advantages, such as low synthesis cost, tunable absorption
range and adjustable energetic level, which effectively provides a wide
light-harvesting window with low energetic loss. However, the power conversion
efficiencies of NFA-based organic solar cell is still lower than mature and
commercial solar cell technology, such as crystalline silicon and perovskite
solar cells. In this thesis, I achieve photovoltaic performance evolution via
novel molecular design, solvent regulation and the introduction of a third
TIME: 04:20 PM - 05:20 PM
LOCATION:Lecture Hall 1 (2322), Engineering and Science Hall (Building 9)
Abstract: In the United States , the topic of CCUS recently received a crucial boost with successful passage of enhanced tax credit legislation (45Q) for CO2 utilization and storage projects. This has resulted in a resurgence of industrial and investment interest in CCUS, and allows greater scrutiny of economic and logistical viability of deployment. Information presented will summarize geologic and engineering perspectives integrated from over a decade of practical project development experience and associated applied research at the Gulf Coast Carbon Center in Texas.
Bio: Dr. Tip Meckel is a senior research scientist investigating geologic carbon storage for the Bureau of Economic Geology at The University of Texas at Austin. Dr. Meckel earned his Master’s degree in geology from the University of Montana in Missoula in 1998 and his doctorate in geology and geophysics from The University of Texas at Austin in 2003. He subsequently had a two-year position with the U.S. Geological Survey as a Mendenhall Postdoctoral Fellow. During his 13 years with the Gulf Coast Carbon Center at the Bureau, he has led research focusing on geologic characterization, structural geology, monitoring design, and pressure evolution for CO2 injections. He has been directly involved with many large-scale field demonstration projects funded through the DOE-NETL Regional Carbon Sequestration Partnerships. After early exposure during the FRIO tests east of Houston in 2006, he co-directed the research program for the SECARB CO2-EOR demonstration project in Cranfield Mississippi, and currently leads the research initiative to identify offshore sequestration potential in the Gulf of Mexico with focus on capacity assessment and high-resolution 3D marine seismic monitoring technologies. Dr. Meckel works closely with offshore CCS developments in China, Japan, and the North Sea. He also leads research for one of the three Energy Frontier Research Centers focusing on CCS in the United States, supported through Basic Energy Sciences, and hosted by the Center for Petroleum and Geosystems Engineering at UT-Austin. Since 2008 he has been PI or Co-PI on 16 CCS grants totaling over $70 million dollars.
DATE: Thursday, October 24, 2019
TIME: 12:00 AM - 12:00 AM
LOCATION:Auditorium (Room 0215) between building 2 & 3
ABSTRACT: Over the past few years, organic-inorganic hybrid perovskites have emerged as a new class of solution processable semiconductor for many optoelectronic applications, such as solar cells and light emitting devices (LEDs). Their electronic, electrical and optical properties can be controlled by tuning their compositions and crystal structures. In this talk, I will discuss how to control the dimension and nanostructure of perovskites by introducing small molecules and polymers with tailored functional groups that can strongly interact with the perovskite crystals. Using such strategy, we have developed very stable Sn-based low bandgap perovskite solar cells with much improved stability and efficiency as well as highly efficient red and blue[3,4] emitting perovskite LEDs. In the second part of my talk, I will discuss how to lean on the experience in interface engineering for organic solar cells and design new electron[5-7] and hole[8-9] transport conjugated materials with proper interfacial properties to improve the charge collection efficiency of perovskite solar cells.Reference: (1) Z. Chen, H.-L. Yip, et al, iScience 2018, 9, 337-346. (2) W. Cai, H.-L. Yip, et al. ACS Appl. Mater. Interfaces 2018, 10, 42564-42572. (3) Z. Chen, H.-L. Yip, et al Adv. Mater. 2017, 29, 1603157. (4) Z. Li, H.-L. Yip, et al Nat. Commun. 2019, 10, 1027(5) S. Chen, H.-L. Yip, M. Wang, F. Huang, et al, Adv. Energy Mater., 2016, 6, 1501534. (6) L. Yan, Q. Xue, H.-L. Yip, et al, Adv. Mater. 2018, 30, 1802509(7) J. Tian, Q. Xue, H.-L. Yip, et al, Adv. Mater. 2019, 31, 1901152(8) Q. Xue, B. Zhang, H.-L. Yip, et al, Adv. Energy Mater., 2016, 6, 1502021.(9) Q. Xue, Y. Li, H.-L. Yip, et al, Adv. Funct. Mater., 2018, 28, 1707444.BIOGRAPHY: Hin-Lap (Angus) Yip is a Professor in the State Key Laboratory of Luminescent Materials and Devices and the Materials Science and Engineering (MSE) Department in South China University of Technology (SCUT). He got his BSc and MPhil degrees in Materials Science from the Chinese University of Hong Kong, and completed his PhD degree in MSE in 2008 under the guidance of Prof. Alex Jen at the University of Washington, Seattle. He joined SCUT in 2013 as full Professor. His current research focuses on the use of an integrated approach combining materials, interface, and device engineering to improve both polymer and perovskite optoelectronic devices. He had published more than 170 scientific papers with citations over 17000 and a H-index of 74. He was also honored as “Highly Cited Researcher” in Materials Science by Thomson Reuters from 2014-2018.
DATE: Sunday, October 27 - Monday, October 28, 2019
DATE: Sunday, October 27, 2019
LOCATION:Building 9, Level 2, Lecture Hall 2, Room 2325
Abstract: High-valent Pd and Ni complexes have been proposed to play an important role in a number of C-C and C-heteroatom bond formation reactions. In this context, a series of stable mononuclear Pd(III) andPd(IV) complexes supported by multidentate N-donor ligands have been synthesized and their oxidative reactivity was investigated. In addition, organometallic Ni(III) and Ni(IV) complexes relevant to cross-coupling reactions have been isolated and their reactivity was studied in detail. The intermediacy of high-valent Pd and Ni species in other organometallic reactions will also be discussed.