Hybrid production system: perspectives in supply chain risk management

Abstract Purpose – From the perspective of the supply chain risk management (SCRM), this paper addresses the effects of a hybrid production system (make-to-stock and make-to-order) in order to know which risks can impact the production planning process at a large automaker in Brazil. Through the correlation of these themes, the purpose of this paper is to understand the relevant risks to the supply chain (SC). Design/methodology/approach – Before the field research, a theoretical approach was made on two themes. After theoretical analysis of a case study on the automaker and data collection, the work used the Pearson’s product moment correlation (r) and χ 2 and Kolmogorov–Smirnov tests to assess the risk factors raised by the interviewed professionals, thus characterizing a mixed methodological approach (i.e. qualitative and quantitative). Findings – It was evidenced that many risks are the result of functional failures, such as input of incorrect information in the system, and many are inherent to managerial decisions when procedures and different paths of production are adopted. Additionally, it has been proven that the adoption of a hybrid production planning approach does not increase the risks to the SC and that the identified risks do not necessarily are included within the scope of SCRM. Originality/value – This study is characterized by an approach which combines SCRM and hybrid production syste

Solvatochromic probes for detecting hydrogen-bond-donating solvents

Hydrogen bonding heavily influences conformations, rate of reactions, and chemical equilibria. The development of a method to monitor hydrogen bonding interactions independent of polarity is challenging as both are linked. We have developed two solvatochromic dyes that detect hydrogen-bond-donating solvents. The unique solvatochromism of the triazine architecture has allowed the development of probes that monitor hydrogen-bond-donating species including water

Azido Groups as Site‐Specific IR Probes of Hydration Around Model Helical Peptides

It has been previously reported by our group and others that the asymmetric stretching\ud band of the aliphatic azido moiety is sensitive to hydrogen bonding of its local environment\ud rather than the electrostatics, and in particular that the azido group is sensitive to an aqueous versus a non-aqueous environment. The azido probe was used to investigate solvation around model helical peptides to provide information about the mechanism of action of a known helix inducer, trifluoroethanol (TFE), in an aqueous solution. Previous studies have hypothesized that TFE acts by dehydrating the backbone of the peptide, although this mechanism is still in dispute. Two azido derivatized amino acids, azido alanine and azido norleucine, were placed in the middle of alanine repeat peptides to report on the first solvation shell around the backbone of the\ud peptide and a solvation shell further out approximating the bulk solution, respectively, using infrared spectroscopy. Circular dichroism experiments were carried out to determine whether\ud the inclusion of an artificial amino acid significantly perturbed the secondary structure of the model peptides, and to find out whether TFE was actually inducing the expected change to the secondary structure of the peptide as it was added to solution. The CD data determined that the\ud azido moiety can be incorporated as a probe without significantly perturbing the secondary\ud structure of the peptide, and the IR data suggest that local TFE clustering around the backbone of\ud the peptide does not occur

Chemical and Biological Controls on Coral Nucleation

Thesis (Ph.D.)--University of Washington, 2021Coral reefs are vibrant and important ecosystems in the oceans, but reefs today are under threat from multiple sources. One such threat is ocean acidification due to anthropogenic climate change, which is reducing both seawater pH and the thermodynamic driving force for CaCO3-based biomineralization (oversaturation or ?). It is known that coral skeletal growth will decrease in an acidifying ocean, but the detailed mechanisms driving this response are still poorly understood. In addition, there is a long-standing debate in the field regarding the relative impact of skeletal organic matrix proteins on calcification and nucleation, with some claiming that these proteins can mitigate the effects of ocean acidification. Nucleation is the first step of the skeleton growing process, and as such is the step that is thought to determine the pace, pattern, and strength of the coral skeleton, and by extension, the development of the very framework that holds reefs together. We made the first quantitative measurements of inorganic aragonite nucleation and its sensitivity to ?, mapping the energy landscape of nucleation kinetics, and finding that it is more sensitive to oversaturation than bulk mineral growth rates in the environmentally relevant range of ? values. Furthermore, we combined inorganic mineral growth rates from the literature with the nucleation rates measured in this work in a numerical model to make predictions about how these two processes work together to affect the overall skeleton. In order to determine the extent of biological control over nucleation, we measured the quantitative effects of a peptide from the acidic domain of a matrix protein from Stylophora pistillata, as well as matrix protein analogues and polypeptides with different functional groups, on nucleation rates and other growth properties. We found that although the matrix protein and analogues had an effect on nucleation, it is unlikely that this protein can counteract the effects of ocean acidification. Overall, this work provides a comprehensive look at inorganic aragonite nucleation and the balance of chemical and biological controls on inorganic rates, as well as how these inorganic studies pertain to corals. These experiments quantify the limits of corals’ ability to respond to the environmental pressure of ocean acidification on skeletal growth

Covalently Bound Azido Groups Are Very Specific Water Sensors, Even in Hydrogen-Bonding Environments

Our first paper (a full paper) on the sensitivity of the azido function group to its local environment, using model compounds. --author-supplied descriptio

Covalently Bound Azido Groups Are Very Specific Water Sensors, Even in Hydrogen-Bonding Environments

Covalently bound azido groups are found in many commercially available biomolecular precursors and substrates, and the NNN asymmetric stretching band of these groups is a strong infrared absorber that appears in a spectral region clear of other signals. In order to evaluate comprehensively the solvatochromism of the asymmetric azido NNN stretching band for site-specific use in biomolecular contexts, infrared spectra of the model compounds 5-azido,1-pentanoic acid and 3-(<i>p</i>-azidophenyl),1-propanoic acid were acquired in a large variety of nonpolar, polar, and hydrogen-bond-donating solvents, as well as mixed aqueous-organic solvents. Spectra in pure solvents indicated that the aliphatic NNN stretching frequency maximum does not depend on solvent polarity, while the aromatic NNN frequency displays a weak but nonzero sensitivity to polarity. In both cases, the NNN frequency exhibits a blue-shift in H-bond-donating solvents, but the frequency in water is higher than in any other H-bond-donating solvent including solvents that are stronger H-bond donors. In nonfluorinated H-bond donor solvents, the frequency blue shift scales with the density of H-bond donors. This sensitivity to the presence of water was further explored in several mixed solvent environments, with the conclusion that this vibrational mode is a highly specific sensor of hydration, even in environments containing other H-bond donors like amides and alcohols, due to the very high local density of H-bond donors in water. The relatively uncomplicated (compared to nitriles, for example), water-specific response of this vibrational mode should lead to its adoption as a site-specific probe of hydration in many different possible systems in which the presence and role of molecular water is of primary interest