abstract: To date, there have not been any studies in a human population that explore the potential of vinegar ingestion in reducing visceral fat, a common yet serious metabolic disease risk factor. However, previous research in animal models exhibit promising findings, showing that vinegar is effective at reducing visceral fat. This is thought to be due to the activation of AMPK (adenosine monophosphate protein kinase) by acetic acid, the active ingredient in vinegar. The purpose of this study was to identify if this potentially groundbreaking relationship exists in human subjects. Healthy, nonsmoking, sedentary adults between the ages 18-45 y and a waist circumference measurement greater than or equal to 33 inches for women and 38 inches for men were recruited for this study. Twenty-three participants completed this 8-week, parallel arm, randomized control trial that tested the efficacy of red wine vinegar consumption (2 tablespoons red wine vinegar, twice per day, before a meal; providing 3.6 g acetic acid) against a placebo (1 apple cider vinegar pill, twice per day, before a meal; providing 0.0225 g acetic acid) for 8 weeks. Participants were randomized into either the vinegar (VIN) or control (CON) group after being stratified by age, gender, waist circumference, and weight. Results found that the VIN group experienced a 2% decrease in visceral fat (cm3, quantified by a DXA scan), but this change did not differ significantly from that of the CON group (p=0.256). The VIN group also experienced a slight decrease in insulin compared to the CON group, but this change was not significantly different than the control change (p=0.125). However, the change in HOMA-IR trended downward in the VIN group (-16%) as compared to the CON group (+9%) (p=0.079) with a large effect size, 0.153. Other parameters did not show statistically significant results between the groups. Further research is indicated in order to examine the potential of vinegar to reduce visceral fat. / Dissertation/Thesis / Masters Thesis Nutrition 2018

abstract: Many people with or at risk for diabetes have difficulty maintaining normal postprandial blood glucose levels (120-140 mg/dl). Research has shown that vinegar decreases postprandial glycemia. The purpose of this study was to examine a possible mechanism by which vinegar decreases postprandial glycemia, particularly the effect of vinegar ingestion on gut fermentation. In this parallel arm randomized control trial, the effects of daily ingestion of vinegar on gut fermentation markers were observed among adults at risk for type 2 diabetes in Phoenix, Arizona. Subjects (n=14) were randomly assigned to treatments consisting of a vinegar drink (1.5g acetic acid) or a placebo (2 vinegar pills containing 40mg acetic acid each). All participants were required to consume the vinegar drink (16 oz) or 2 placebo pills every day for 12 weeks. At week 12, participants filled out a questionnaire to report gastrointestinal (GI) symptoms and three consecutive breath samples were taken from each subject to measure fasting breath hydrogen (BH2) with a breath analyzer. Fasting BH2 measures for the vinegar drink group (16.1+11.8 ppm) were significantly different than those from the pill group (3.6+1.4) with a partial eta squared of 0.39 (p=0.023). After adjusting for age as a confounding factor (r=0.406) and removing an outlier, fasting BH2 measures for the vinegar drink group (4.3+1.1 ppm) were still significantly different than those from the pill group (3.6+1.4) with a partial eta squared of 0.35 (p=0.045). Participants in both groups reported mild changes in GI symptoms. In conclusion, adults at risk for type 2 diabetes that consume 2 tablespoons of vinegar a day may have increased gut fermentation compared to those who do not consume vinegar. / Dissertation/Thesis / M.S. Nutrition 2013

Abstract More than 900 papers related to organosolv pulping have been reviewed in this thesis. From the information included in those papers it can be concluded that organosolv pulping processes are still in a developing stage and are not yet ready to seriously threat the position of the kraft process as the main pulp manufacturing process in the world. Distillation seems to be the main alternative as the process for recovering the solvent in organosolv pulping. A good reason for this is that using simple distillation no potentially harmful components are introduced to the process. The effect of feed composition on the operation of a separation sequence in an organosolv process using aqueous formic and acetic acids and corresponding peroxyacids was studied. When simple distillation was used as the separation method the effect was found to be significant. The no ideal nature of the formic acid-acetic acid-water mixture, which separation was studied, makes the ternary composition space to divide into four distillation regions. Which region the feed is located in, obviously determines the economy of the distillation sequence. Shortcut calculation methods cannot be recommended to be used for designing a distillation sequence for the ternary mixture studied, but they give useful information for the comparison of such sequences. They were used to choose a limited number of alternatives for studies with rigorous calculation methods. Minimum work of separation can also be used to make a satisfying estimate for the relative easiness of separation of the formic acid-acetic acid-water mixture. Thermal integration using pinch technology was also tested and found very useful for decreasing the thermal energy consumption of distillation processes. Thermodynamic efficiencies for separating the formic acid-acetic acid-water mixture by simple distillation were estimated. They were found to be lower than the average value for distillation presented in literature.

In this research, the corrosion performance of two austenitic stainless steels, namely 316L and 254SMO, in concentrated acetic acid solutions containing bromide ions has been investigated. In this research, the influence of two different electrochemical surface treatments (electropolishing and nitric acid passivation) on the corrosion behaviour of 316L stainless steel immersed in 15.3M HAc with 18.7mM bromide ions at 900°C was examined. Also, attemptswere made to study the performance of three organic inhibitors in the same conditions. Corrosion rates are assessed both by weight loss, and linear polarisation resistance. Interfacial corrosion chemistry is further characterised by open circuit potential and potentiodynamic polarization measurements. Substrate morphology is elucidated with optical microscopy, including 3D surface profiling, and scanning electron microscopy. Also, X-ray photoelectron spectroscopy is employed to gain further insight into the quite differentcorrosion performances of 316L and 254SMO in 15.3M acetic acid with 18.7mM Br ions.It was found that 316L and 254SMO steels have good corrosion resistance and low corrosion rates in 11.9M-HAc-Br-. Increasing acid concentration to 15.3 M led to a dramatic increase in corrosion rate of 316L with clear evidence of uniform and pitting corrosion proceeding simultaneously. Notably, the step increase in OCP for 316L steel and 254SMO during immersion in 15.3M-HAc-Br- solution indicates sudden changes in corrosion activity of the steels. The step seen for the 254SMO in 15.3M-HAc-Br- is indicative of passivation which is also supported by the XPS results, as a stable passive film was observed on the surface of alloy over the immersion time. However, the step increase in the OCP observed for 316L in 15.3MHAc-Br- is not associated with a significant decrease in corrosion rate. An alternative explanation is that the step coincides with an increase in the importance of pitting due to the evolving surface structure.From the attempts which were made to improve the corrosion resistance of the 316L stainless steel in 15.3M-HAc-Br-, both electropolishing and nitric acid passivation treatments were not sufficient to give any noticeable protection from the aggressive solution. Also, no corrosion inhibition was achieved when the three organic inhibitors, BTA, TU and 2MBI were utilised.

This study investigated the corrosion processes at the top and bottom of carbon steel pipelines transporting wet gases, and studied possible chemical mitigation strategies. First, immersion tests were carried out using carbon steel to study the effects of de-aeration with high purity nitrogen gas on the corrosion rate. Secondly, the corrosion rate was assessed for varying chloride ion concentrations in an aerated environment. In general, increasing de-aeration time changes the corrosion mechanism from mass transfer oxygen reduction to water reduction reaction. However, oxygen solubility controlled the corrosion process in aerated solution containing different chloride ion concentrations. A special two-electrode cell was designed for the top of the line corrosion (TLC) electrochemical measurements but a conventional three electrode cell was used for the bottom of the line corrosion (BLC) measurements. The TLC rate increases with temperature, and X-Ray Diffraction (XRD) confirmed the presence of chukanovite {Fe2(CO3)(OH)2}and possibly ferrous carbonate corrosion products at 40oC and 60oC respectively. However, for the BLC, the cementite phase remained on the metal surface after preferential dissolution of the ferrite phase in the carbon steel. Addition of acetic acid (HAc) locally dissolved the initially FeCO3 film formed on the metal surface, causing local corrosion damage. Addition of methyl di ethanol amine (MDEA) as a pH stabiliser reduced TLC and BLC rates due to enhanced stability of FeCO3 at pH 5.7-6.3. When Zn2+ ions were added as ZnCl2, both Fe2O3 and ZnCO3 were formed at reduced corrosion rate. Whenever FeCO3 film was damaged/dissolved by HAc addition of neither pH stabiliser; MDEA nor hydrate preventer; mono ethylene glycol (MEG) could not re-establish a protective film on the metal surface. The following organic inhibitors were investigated as potential mitigators of TLC: 2-mercaptobenzimidazole (2MBI), 2-amino-5-ethyl-1,3,4-thiodiazole (AETDA), 2-phenyl-2-imidazoline (2PI), dicyclohexylamine (DHA), and a commercial inhibitor formulation (CI-A). The inhibition efficiency (IE%) was found to increase in the order CI-A > 2MBI > AETDA > DHA. Their efficiency increases (except DHA) with inhibitor concentrations both at top and bottom of the line. 2MBI and CI-A behaved as mixed inhibitors but AETDA behaved as cathodic inhibitor, all were best fitted to a simple Langmuir adsorption isotherm. However, IE% of DHA decreased at higher inhibitor concentrations. Surprisingly, 2PI inhibitor increased the corrosion rate, and the corrosion rate further increased with increase inhibitor concentrations. Weight loss measurements results of TLC are also presented which showed lower inhibition efficiency for all the inhibitors investigated compared with electrochemical measurements in similar environments. The free energy of adsorption (∆Goads values for 2MBI and AETDA are around -36kJ.mol-1 while for CI-A the value was -15kJ.mol-1 (-7kJ.mol-1 in the presence of HAc). This is evidence for adsorption of 2MBI and AETDA on the metal surface by chemisorption with CI-A by physisorption. XPS analysis confirmed the presence of FeCO3 and FeOOH as corrosion products in the brine solution in the absence and presence of HAc containing different corrosion inhibitors.

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>Magister Scientiae - MSc / This study presents the successful characterization and hydrolysis of magnesium hydride (MgH2) for hydrogen generation. The as-received MgH2 served as a precursor in most of the hydrolysis experiments for H2 generation. The phase-structural and morphological characteristics of the as-received MgH2 were evaluated using scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray dispersive diffraction (XRD) characterization techniques. The hydrogen storage performance of the as-received MgH2 was analysed by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and thermal desorption spectroscopy (TDS) techniques. The hydrolysis of MgH2 was performed in a hydrogen generation reactor operated in a batch mode where the temperature and H2 flow rate were logged.

Objective. To assess the acceptability of cervical screening using direct visual inspection after acetic acid application followed by immediate cryotherapy for cervical intraepithelial neoplasia among women in rural Guatemala. Materials and Methods. An unselected group of 1,052 women voluntarily registered to undergo cervical screening using direct visual inspection of the cervix after acetic acid application. Women with acetowhite changes consistent with cervical intraepithelial neoplasia were offered immediate cryotherapy. Results. Cervical screening was deferred in 80 (7.6%) registrants, and 18 (1.7%) refused to undergo an examination. Among the 954 registrants screened, 125 (13%) had findings consistent with cervical intraepithelial neoplasia. Cryotherapy was deferred in three patients. A total of 121 (99%) women agreed to immediate cryotherapy. Conclusion. Direct cervical visualization after acetic acid application followed by immediate cryotherapy for acetowhite changes consistent with cervical intraepithelial neoplasia would be a well-accepted method of cervical screening in rural Guatemala.

No description available.

No description available.