Papers by Michael Mario Condori Ramirez
Water Resources Management, 2014
ABSTRACT Boat-based field data and monitoring station data from the tidal reach of the Mississipp... more ABSTRACT Boat-based field data and monitoring station data from the tidal reach of the Mississippi River are utilized to examine the sediment capture of large (>1,400 cms) proposed water and sediment diversions from the channel to build and sustain wetlands in the Mississippi delta. The purpose herein is to suggest the importance of siting the diversion relative to river morphology and operating it to optimize sediment capture. At the site of a proposed diversion near Myrtle Grove, LA, water and sediment data suggest that the washload (fine) fraction is strongly weighted toward the rising limb of individual freshets (e.g., flows >16,990 cms, 1 to 5 events/y over the last 49 y) based on daily turbidity records. Significant variability in suspended fines exists between freshets depending on whether they are the first peak of the water year, and on their tributary source. Much of the sand fraction in suspended load, since it is derived from the underlying bed (e.g., bed material load), is strongly tied to water discharge in this reach, and can be accurately predicted by ratings curve. An analytical model is presented that is utilized to test efficiency of sand capture in a diversion based on ADCP backscatter data calibrated by isokinetic water samplers. Using observations from the diversion site, the model predicts a 30 % more efficient sand capture for a 1,416 cms diversion (0–10 m withdrawal depth) at a discharge of 27,250 cms (March 2011) on the proposed lateral bar diversion site, relative to a thalweg site on the opposite bank. This suggests that the proximity of large dunes, and the turbulence induced by them, is a primary control on sand resuspension in the water capture zone, which in turn plays a strong role in efficiency of diversion sand capture.
Journal of Geophysical Research: Earth Surface, 2013
Understanding specific pathways for sand transport in the lower reaches of large rivers, includin... more Understanding specific pathways for sand transport in the lower reaches of large rivers, including the Mississippi, is a key for addressing multiple significant geologic problems, such as delta building and discharge to the oceans, and for environmental restoration efforts in deltaic environments threatened by rising sea levels. Field studies were performed in the Mississippi River 75-100 km upstream of the Gulf of Mexico outlet in 2010-2011 to examine sand transport phenomena in the tidally affected river channel over a range of discharges. Methods included mapping bottom morphology (multibeam sonar), cross-sectional and longitudinal measurements of water column velocity and acoustic backscatter, suspended sediment sampling, and channel-bed sampling. Substantial interaction was observed between the flow conditions in the river (boundary shear stress), channel-bed morphology (size and extent of sandy bedforms), and bed material sand transport (quantity, transport mode, and spatial distribution). A lateral shift was observed in the region of maximum bed material transport from deep to shallow areas of subaqueous sand bars with increasing water discharge. Bed material was transported both in traction and in suspension at these water discharges, and we posit that the downriver flux of sand grains is composed of both locally-and drainage basin-sourced material, with distinct transport pathways and relations to flow conditions. We provide suggestions for the optimal design and operation of planned river diversion projects.
Sensors, and Command, Control, Communications, and Intelligence (C3I) Technologies for Homeland Security and Homeland Defense V, 2006
Characterization of peroxide-based explosives by thermal analysis. [Proceedings of SPIE 6201, 620... more Characterization of peroxide-based explosives by thermal analysis. [Proceedings of SPIE 6201, 62012B (2006)]. Michael L. Ramírez, Leonardo C. Pacheco-Londoño, Álvaro J. Peña, Samuel P. Hernández-Rivera. Abstract. Peroxide ...
Polymer Degradation and Stability, 2002
This document is disseminated under the sponsorship of the U.S. Department of Transportation in t... more This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The United States Government assumes no liability for the contents or use thereof. The United States Government does not endorse products or manufacturers. Trade or manufacturer's names appear herein solely because they are considered essential to the objective of this report. This document does not constitute FAA certification policy. Consult your local FAA aircraft certification office as to its use. This report is available at the Federal Aviation Administration William J. Hughes Technical Center's Full-Text Technical Reports page: actlibrary.tc.faa.gov in Adobe Acrobat portable document form (PDF).
Selected Topics on Optical Fiber Technology, 2012
SPIE Proceedings, 2005
The objective of this research is to design and develop a multi-sensor capable of fast detection ... more The objective of this research is to design and develop a multi-sensor capable of fast detection and of recognition optimization of the techniques for used for quantification of TATP by Pattern Recognition. In particular, the long range goal of the research is to use sensor fusion and sensor "talking" modalities to couple Stand Off detectors with Chemical Point detectors for detection of airborne chemical agents and detection of Improvised Explosive Devices (IEDs). Vibrational spectroscopy techniques are very fast and can be used for real time detection. Good results have been obtained with various target molecular (chemical) systems such as TATP, TNT and DNT. Samples of TATP were detected and quantified in air, in solution and in solid phase on surfaces by different techniques. FTIR Spectroscopy and GS-MS were used to generate new analytical procedures for detection and analysis of the organic peroxide. These procedures were compared and taken to their limits by optimization with Chemometrics, Partial Least Squares (PLS), and Discriminant Analysis (DA).
Infrared Technology and Applications XXXIII, 2007
Fiber optics coupled-grazing angle probe Fourier transform infrared (FTIR) spectroscopy and infra... more Fiber optics coupled-grazing angle probe Fourier transform infrared (FTIR) spectroscopy and infrared microspectroscopy have been used for characterization of the distribution and form of layers of some explosives deposited on stainless steel sheets. Among the explosives tested were trinitrobenzene, HMX and Tetryl. Various solvents were used to deposit the films on stainless steel slides. Isopropyl alcohol was the preferred solvent
SPIE Proceedings, 2007
The use of liquid explosives by terrorists has raised the attention to the use of hazardous liqui... more The use of liquid explosives by terrorists has raised the attention to the use of hazardous liquids as threats to people, buildings and transportation systems. Hazardous liquids such as explosive mixtures, flammables or even chemical warfare agents (CWA) can be concealed in ...
Infrared Technology and Applications XXXII, 2006
An actively operated standoff infrared detection system was designed from commercial infrared equ... more An actively operated standoff infrared detection system was designed from commercial infrared equipment: VECTOR 22 FTIR (Bruker Optics), an external mirror and an external MCT detector. One type of experiment was done for IR detection of high explosives RDX and TNT on reflective surfaces. In the detection on surface, the samples were move to different distances and a beam of
Sensors, and Command, Control, Communications, and Intelligence (C3I) Technologies for Homeland Security and Homeland Defense V, 2006
Novel method for the preparation of explosives nanoparticles. [Proceedings of SPIE 6201, 620129 (... more Novel method for the preparation of explosives nanoparticles. [Proceedings of SPIE 6201, 620129 (2006)]. Marcos A. Barreto-Cabán, Leonardo Pacheco-Londoño, Michael L. Ramírez, Samuel P. Hernández-Rivera. Abstract. ...
Chemical and Biological Sensing VIII, 2007
This work was focused in the measurement of spectroscopic signatures of Chemical Warfare Agent Si... more This work was focused in the measurement of spectroscopic signatures of Chemical Warfare Agent Simulants (CWAS) and degradation products of chemical agents using vibrational spectroscopy for the.
SPIE Proceedings, 2005
Characterization of thermal inkjet technology TNT deposits by fiber optic-grazing angle probe FTI... more Characterization of thermal inkjet technology TNT deposits by fiber optic-grazing angle probe FTIR spectroscopy. [Proceedings of SPIE 5778, 543 (2005)]. Oliva M. Primera-Pedrozo, Leonardo Pacheco-Londono, Orlando Ruiz ...
Pancreatology, 2006
To evaluate the capacity of enteral nutrition, in comparison with the total parenteral nutrition ... more To evaluate the capacity of enteral nutrition, in comparison with the total parenteral nutrition (TPN) plus antibiotic therapy, for avoiding pancreatic necrosis infection in the severe acute pancreatitis. In the period between October 1998 and September 2003, 87 patients met the inclusion criteria and took part in this research. Within the first week from their admission, 43 patients received TPN and 44 patients received total enteral nutrition (TEN). An adequate prophylactic antibiotic therapy was used in both groups. The severity of the manifestations was similar for both groups having a tomographic 'severity index' of 8 and an entry C-reactive protein of 208 and 203 mg/l, respectively. The group that received TPN suffered an organ failure in 79% of the cases, while the percentage showed by the group that received TEN was 31%; 88 and 25% of the patients in each group requiring a surgical intervention, respectively (p < 0.001). There was decreased presence of pancreatic necrosis infection in the group of patients that was supplied with TEN (20%) than in the group receiving TPN, where it reached 74% (p < 0.001). The death rate was significantly higher among the patients who received TPN, (35%), while for the patients who received TEN it was only 5% (p < 0.001). TEN could be used as a prophylactic therapy for infected pancreatic necrosis since it significantly diminished the necrosis infection as well as the mortality.
Molecular Cancer Research, 2013
Tumor necrosis factor (TNF)-α promotes tumor development under chronic inflammation. Because TNF ... more Tumor necrosis factor (TNF)-α promotes tumor development under chronic inflammation. Because TNF also activates caspase-8, selective inhibition of TNF-induced extrinsic apoptosis would be required for inflammation-associated tumor growth. In a mouse model of inflammation-associated colon carcinogenesis, we found nuclear expression of β-catenin in tumors of wild-type, but not mutant, mice that were made resistant to TNF-induced apoptosis by a germline mutation blocking caspase cleavage of the retinoblastoma (RB) protein, despite similar frequencies of β-catenin exon-3 mutations in these two genetic backgrounds. TNF-induced apoptosis was also attenuated in human colon cancer cell lines with genetically activated β-catenin. However, we found that HCT116 cells, which contain an activated allele of β-catenin but do not express nuclear β-catenin, were sensitive to TNF-induced apoptosis. In HCT116 cells, TNF stimulated efficient RB cleavage that preceded chromatin condensation. In contrast...
Molecular Biology of the Cell, 2012
The Wnt/β-catenin pathway is constitutively activated in more than 90% of human colorectal cancer... more The Wnt/β-catenin pathway is constitutively activated in more than 90% of human colorectal cancer. Activated β-catenin stimulates cell proliferation and survival, however, its antiapoptotic mechanisms are not fully understood. We show here that activated β-catenin is required to suppress caspase-8 activation, but only in colon cancer cells that are resistant to tumor necrosis factor-α (TNF)-induced apoptosis. We found that lysosomal delivery of internalized TNF occurred at a faster pace in apoptosis-resistant than in apoptosis-sensitive colon cancer cells. Retardation of endosomal trafficking through vacuolar ATPase (V-ATPase) inhibition enhanced caspase-8 activation in apoptosis-resistant but not apoptosis-sensitive cells. Interestingly, knockdown of β-catenin also prolonged TNF association with the early endosome and enhanced caspase-8 activation in apoptosis-resistant but not apoptosis-sensitive colon cancer cells. In a mouse model of inflammation-associated colon tumors, we foun...
Journal of Thermal Analysis and Calorimetry, 2010
Page 1. Thermal-spectroscopic characterization of acetone peroxide and acetone peroxide mixtures ... more Page 1. Thermal-spectroscopic characterization of acetone peroxide and acetone peroxide mixtures with nitrocompounds Michael L. Ramırez Hilsamar Félix-Rivera Rhaisa A. Sánchez-Cuprill Samuel P. Hernández-Rivera ...
Journal of Hydrology, 2013
The large Mississippi River flood in 2011 was notable in the lowermost Louisiana, USA reach for r... more The large Mississippi River flood in 2011 was notable in the lowermost Louisiana, USA reach for requiring operation of several flood control structures to reduce stress on artificial levees: the largest diversion went through the gated Bonnet Carré Spillway, which was opened for 42 days in May and June. The removal of approximately 20% of the total flood discharge from the river provided an opportunity to examine the impact of large water diversion on the sediment transport capacity of large rivers. Boat-based, acoustic and water and bed sampling surveys were conducted in the Mississippi River channel adjacent to the Spillway immediately prior to the opening of the structure, at full capacity, and immediately following (June 2011) and 1 year after (June 2012) closure. The surveys were designed to examine (1) elevation change of the channel bed due to scour or aggradation of sediment, and (2) suspended and bedload transport variability upriver and downriver of the Spillway. The results indicate that approximately 9.1 million tons of sand were deposited on the channel bed immediately downriver of the water exit pathway and extending at least 13 km downriver at a rapidly and progressively reducing magnitude per river kilometer. The surficial deposit was of finer grain size than the lateral sand bars in the channel upriver of the structure. We argue the deposit was largely delivered from suspension derived from the observed deflation of lateral bars upstream of the diversion point, rather than from sand arriving from the drainage basin. Approximately 69% of the 2011 flood deposit was removed from the 13 km downstream reach between June 2011 and June 2012. We conclude that the source of the channel deposit was the reduction in stream power, and, thus, in the sediment transport capacity of the Mississippi, associated with the water withdrawal. The re-entrainment of this material in the following flood year indicates the system rapidly re-establishes an equilibrium to pre-opening conditions. Future diversions in the river for coastal restoration will have to address this issue to maintain a deep draft navigation channel in the Mississippi River.
High Performance Polymers, 2007
The chemistry and properties of polymers containing the “fire smart” moiety 1,1-dichloro-2,2-diph... more The chemistry and properties of polymers containing the “fire smart” moiety 1,1-dichloro-2,2-diphenylethene (DDE) are described. These polymers are typically derived from the bisphenol of chloral (bisphenol-C/BPC) and are low cost, easily processed, and have good mechanical properties and toughness under normal conditions. Under fire conditions, the DDE group undergoes an intramolecular rearrangement with the elimination of hydrogen chloride (a noncombustible gas) and intermolecular crosslinking to form an aromatic char residue in high yield. The flammability and mechanical properties of DDE-containing polymers are described.
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Papers by Michael Mario Condori Ramirez