Henrys Law Constant Of Glyoxal Research Paper Example | Topics and Well Written Essays - 3500 words

Henrys Law Constant Of Glyoxal - Research Paper Example The enhancement of KH was linked to the sulfate: carbonyl molar ratio rather than the absolute concentration of sulfate ions in bulk solution. The profound sulfate effect was only observed in glyoxal and formaldehyde, but not methylglyoxal. Chemical analysis suggested that this sulfate mediated reaction was reversible. Meanwhile, Time of Flight-MS (TOF-MS), NMR spectroscopy and X-ray diffraction (XRD) suggested the unknown product was sulfate containing product. For ionic strength effect, KH of formaldehyde, methylglyoxal and glyoxal were investigated in NaCl solution with concentrations ranging from 25mM to 4M. Our observation suggested that the formation of hydrogen bonding between chloride ions and diol groups of the hydrated carbonyls lead to "salting-in" effects in concentrated NaCl solution. The partitioning process of these small, reactive carbonyls was not sensitive to the ionic strength of wet aerosols and the profound effects of sulfate on glyoxal KH supported the hypothesi s that sulfate play an important role in glyoxal gas/aqueous phase partitioning. The Henry law constant KH is a key parameter that aids in the... 2.2 Experimentation Methods 6 3.0 Results and Discussion 7 3.1 Formaldehyde 7 Product Identification 9 3.2 Glyoxal 10 3.3 Methylglyoxal 13 4.0 Conclusion 14 Work cited 16 Appendix 25 1.0 Introduction The Henry law constant KH is a key parameter that aids in the determination of the magnitude, rate and flux direction between the aqueous and the gas solution. Due to the insufficient thermodynamic data and poor understanding in gas/particle partitioning behaviors of glyoxal and other oxidation products from both anthropogenic and biogenic volatile organic compounds (VOCs), discrepancies between field measurements and SOA models were large (Volkamer et al., 2006). In particular, the partitioning process of C2, C3-bifunctional species, formed in significant yields from the photo-oxidation of aromatic hydrocarbons, isoprene, terepene, alkenes as well as alkynes, remain unclear [Yu et al., 1995; Yu et al., 1997; Yu et al., 1998; Yu et al., 1999; Warneck, 2003]. Field measurements have revealed that these low molecular weight, bi-functional species are important precursors for SOA in cloud-processing [Blando and Turpin, 2000; Warneck, 2003]. Laboratory evidence suggests that, the rate-limiting step in SOA formation of isoprene photo-oxidation was the oxidation of first-generation reaction products which leads to the formation of up to four functional groups of the carbon skeleton. Therefore, the partitioning of chemical species containing multifunction groups could be more likely a critical step for formation of SOA in other systems as well (Kroll et al, 2006). Recently, glyoxal was used as an activity indicator for photo-oxidation attributed to its high abundance after onset of sunlight and short lifetime, while formaldehyde worked

Prevention of mother to child Hiv transmission Essay

Prevention of mother to child Hiv transmission - Essay Example Quantitative research is the methodical scientific assessment of observable phenomena through computational, mathematical, or statistical methods. For example, the observable phenomena in health and social care may include HIV prevalence in expectant mothers, rate of mother to child HIV transmission, and infant deaths resulting from mother to child HIV transmission. Quantitative uses a systematic approach through actual data collection and analysis rather than making assumptions on describable phenomena. The purpose of the quantitative approach is to develop hypothesis about the observable phenomena. The research technique goes a long way in testing the hypotheses or theories so developed in order to ascertain their veracity or otherwise. In social and nursing care, scholars may use quantitative research to develop hypotheses around mother to child HIV transmission. The testing and proof of such hypothesis can bring significant benefit to the nursing fraternity (Daly, Speedy, & Jacks on 2009, pp. 135-140). Health and social care demands evidence-based practice, which quantitative research provides in hard data. In essence, evidence-based practice (EBP) or Evidence-based medicine (EBM) is the point at which the patient values & preferences, best research evidence, and clinical expertise converge. Evidence-based practice (EBP) involves the prudent utilization of the most reliable contemporary evidence in making critical decisions about the health of patients.