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Search Results: 1 - 10 of 1833 matches for " Aldo Okullo "
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Energy Targeting for a Brewing Process Using Pinch Analysis  [PDF]
Noah Tibasiima, Aldo Okullo
Energy and Power Engineering (EPE) , 2017, DOI: 10.4236/epe.2017.91002
Abstract: The rising cost of energy and environmental concerns have led the brewing industry to search for techniques of reducing energy consumption in brewery operations. In this paper, pinch analysis was applied to a typical Ugandan based brewery process to target for the energy requirements of the process. Hint software was used for the analysis. At the chosen ΔTmin of 10, the minimum cooling and heating utility requirements of the brewery studied were determined as being 4862.21 kW and 8294.21 kW respectively, with a pinch temperature at 68. It was observed that using the technique, 1806.59 kW of energy could be recovered through process to process heat exchange which presented an energy saving potential of 21.5%. It is recommended that results from this study could be used in the design or retrofit of a heat exchanger network of a brewery for improved energy efficiency. Considerations can also be made for other values of ΔTmin.
Modelling the Kinetics of Jatropha Oil Transesterification  [PDF]
Aldo A. Okullo, Abraham K. Temu
Energy and Power Engineering (EPE) , 2015, DOI: 10.4236/epe.2015.74013
Abstract: Kinetics of a chemical reaction provides an important means of determining the extent of the reaction and in reactor designs. Transesterification of jatropha oil with methanol and sodium hydroxide as a catalyst was conducted in a well mixed reactor at different agitation speeds between 600 and 800 rpm and temperature range between 35°C and 65°C. The effect of variation of temperature and mixing intensity on rate constants were studied. The initial mass transfer controlled stage was considered negligible using the above impeller speeds and second order mechanism was considered for the chemically controlled kinetic stage. Samples were collected from the reaction mixture at specified time intervals and quenched in a mixture of tetrahydrofuran (THF) and sulphuric acid. The mixture was centrifuged at 2000 rpm for 15 minutes and the methyl ester was separated from the glycerol. The ester was washed with warm water (50°C), dried and analysed using gas chromatography coupled with flame ionization detector (GC/FID) to determine free and total glycerine and methyl ester. A mathematical model was fitted using second order rate law. High temperature and high mixing intensity increased reaction rates. The model fitted well with a high correlation coefficient (R2) of 0.999.
Modeling and Simulation of an Isothermal Suspension Polymerization Reactor for PMMA Production Using Python  [PDF]
Aldo Okullo, Noah Tibasiima, Joshua Barasa
Advances in Chemical Engineering and Science (ACES) , 2017, DOI: 10.4236/aces.2017.74029
This paper presents the modeling and simulation of a suspension polymerization for methyl methacrylate in an isothermal reactor to produce poly methyl methacrylate using Python 3.5. The numeral solution to the stiff ordinary differential equations was performed by building a custom module which was used with the inbuilt NumPy and matplotlib modules that come with the Anaconda python distro. Python was used in order to obtain a realistic solution that considers the gel, glass and cage effects that affect the non-linear polymerization kinetics established in literature. The results showed that a maximum monomer conversion of about 92.8% at a minimum batch time of about 2.2 hours could be achieved at the specified conditions to obtain a polydisperse polymer with an index of 27. It is further concluded that Python can be employed to perform similar studies with equal success as any other programming language.
Validity and reliability of the Oral Impacts on Daily Performance (OIDP) frequency scale: a cross-sectional study of adolescents in Uganda
Anne ?str?m, Isaac Okullo
BMC Oral Health , 2003, DOI: 10.1186/1472-6831-3-5
Abstract: 1146 adolescents (mean age 15.8, response rate 87%) attending secondary schools in Kampala (urban) and Lira (rural) completed a survey instrument designed to measure subjective oral health indicators including the eight-item OIDP frequency scores. A clinical examination was conducted among 372 students (mean age 16.3, response rate 72%) and caries was assessed following the World Health Organisation criteria (1997).62% of the students experienced at least one oral impact during the 6 months preceding the survey. Cronbach's alpha for the OIDP frequency items was 0.91 and the corrected item-total correlation ranged from 0.62 to 0.75. Discriminant and construct validity were demonstrated in that the OIDP scores varied systematically in the expected direction with missing teeth and self-report indicators of oral health status, respectively. Socio-demographics and dental attendance did not predict OIDP through interaction with clinical indicators but varied systematically and independently with OIDP frequency scores in the multivariate analysis.the OIDP frequency score have acceptable psychometric properties in the context of an oral health survey among Ugandan adolescents. Some evidence of the importance of social and personal characteristics in shaping adolescents' responses to oral disorders was provided.In response to the growing recognition of quality of life measurement in health care, socio-dental indicators, designed to assess the functional and psychological outcomes of oral disorders, have been developed and tested in various populations [1,2]. Most of the research on oral health related quality of life has been performed with adults and older people and there are only few studies from outside North-America and Europe [1-3,5,6]. Uncertainty remains as to the use of socio-dental indicators in youth populations generally and to their applicability in non-western cultural settings, specifically.The Oral Impacts on Daily Performance (OIDP) scale [5] assesses impact
On the Expansion and Fate of the Universe  [PDF]
Aldo Bonasera
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.311212
Abstract: The evolution of the universe from an initial dramatic event, the Big-Bang, is firmly established. Hubble’s law [1] (HL) connects the velocity of galactic objects and their relative distance: v(r) = Hr, where H is the Hubble constant. In this work we suggest that HL is not valid at large distances because of total energy conservation. We propose an expansion of the velocity in terms of their relative distance and produce a better fit to the available experimental data. Using a simple “dust” universe model, we can easily calculate under which conditions an (unstable) equilibrium state can be reached and we estimate the values of the matter present in the universe as well as the “dark energy”. Within the same formalism we can derive the “deceleration parameter”. We do not need to invoke any “dark energy”, its role being played by the kinetic correction. The resulting picture is that the universe might reach an unstable equilibrium state whose fate will be decided by fluctuations: either collapse or expand forever.
An Unusual Case of Stercoral Perforation in a Patient with 86?cm of Small Bowel
Alfin Okullo,Ghiyath Alsnih,Titus Kwok
Case Reports in Surgery , 2013, DOI: 10.1155/2013/317250
Abstract: A 77-year-old male who previously had extensive enterectomy due to ischaemic gut with loss of all but 86?cm of jejunum in addition to a right hemicolectomy presented to the emergency department (ED) with abdominal pain and constipation of 12-day duration. Abdominal imaging with X-ray and CT revealed pneumoperitoneum in addition to a grossly redundant and faecally loaded colon. At laparotomy, rectal perforation was found. In view of the patient’s advanced age, comorbidities, and the absence of intraperitoneal faecal contamination, manual disimpaction followed by wedge resection and primary closure of the perforation was done. On postop day 11, a perforation in the sigmoid colon with free subdiaphragmatic gas was picked up on CT after a work up for abdominal tenderness. In the absence of peritonism and other signs of deterioration, conservative management was chosen with subsequent uneventful recovery for the patient. 1. Introduction A patient with 86?cm of small bowel is expected to have short bowel syndrome (SBS). It is quite unusual for such a patient to present with constipation so severe that it causes stercoral perforation. We present a rare case of one such patient. 2. Case Report A 77-year-old male presented to the (ED) with generalized abdominal pain and constipation of about 12-day duration. He was still passing wind and denied any nausea or vomiting. His previous surgical history consisted of an extensive enterectomy 17 years ago for ischaemic gut, whereupon all but 86?cm of his jejunum was resected in addition to a right hemicolectomy. A jejunal-transverse colon anastomosis was done. Back then, his postop recovery was notable for a quick resolution of his diarrhea while on a low-fibre diet without any antimotility drugs and a return to his premorbid, chronically constipated state within about 2 months of the surgery. He thereafter required daily lactulose whose dose he had increased from 20 to 30 mls to no avail over the past 12 days. He was never on any medicines used to treat short bowel syndrome. A review of his regular medications was negative for any that would contribute to his chronic constipation prior to and after the bowel resection 17 years ago. At this presentation, his vital signs and blood tests were all normal except for an INR of 6.6. A chest X-ray revealed free subdiaphragmatic gas (Figure 1), while a plain erect abdominal X-ray showed gross faecal loading. Figure 1: CXR demonstrating air under the diaphragm on presentation. A CT abdomen and pelvis with oral and intravenous contrast demonstrated gross faecal loading in the
Effect of Mode of Auxin Application on Rooting and Bud Break of Shea Tree (Vitellaria paradoxa) Cuttings  [PDF]
Moses Okao, Lawrence Ogwal, Gloria Mutoni, Samuel Oyuko Alip, John Bosco Lamoris Okullo, Clement Akais Okia
American Journal of Plant Sciences (AJPS) , 2016, DOI: 10.4236/ajps.2016.715194
Abstract: Vegetative propagation by stem cutting is an important technique applied for agricultural production where rooting success is one of the major aspects. A study to assess the effects of mode of application of rooting hormones (IBA) on adventitious root formation of V. paradoxa stem cuttings was conducted. Accordingly, four application methods were investigated in a 4 × 3 factorial experiment using a Completely Randomized Design (CRD). The application methods were: 24-hour extended soak, foliar spraying, basal quick dip and delayed IBA application method. Thus, the parameters used to determine rooting success were mean root length and root number. The effect of these application methods on occurrence of bud break was also considered. On the whole, root length was observed to be a function of IBA concentration, whereby root length increased significantly (P ≤ 0.05) with an increment in IBA concentration. Stem cuttings subjected to 24-h extended soak at 100 ppm rooted best (59.5% ± 8.33%), where as foliar sprayed stem cuttings exhibited the worst rooting success (11.9 ± 3.06 - 23.8% ± 4.16%). Bud break appeared to decrease with increasing IBA concentration and delaying IBA application enhanced rooting percentage of the quick dip method by 7.1%, 9.5% and 11.9% at 2500 ppm, 3500 ppm and 4500 ppm, respectively. The extended soak method of IBA application at 80 ppm shows potential for large scale production of V. paradoxa through stem cuttings.
Online Educational Resources Regarding Cardiovascular Prevention  [PDF]
Aldo T. Marrocco
E-Health Telecommunication Systems and Networks (ETSN) , 2015, DOI: 10.4236/etsn.2015.41002
Abstract: This paper presents several informative and educational tools aimed to explain some mechanisms of Miocardial Infarction and Stroke, their risk factors and their prevention. Such educational and informative documents are in English and consist of texts, images, videos, animations and games. They are downloadable for free and can be used with the method considered by the teacher as most appropriate. Among the aims of the study is to provide information on the effects which some of our daily actions may have on the circulatory system. The pathological processes affecting blood vessels may start to develop during childhood or adolescence as a consequence of physical inactivity, unhealthy diet, smoking and alcohol abuse. Notoriously, unhealthy behaviours learned in early age are very likely to be continued in the adulthood. By the time they can lead to important car-diovascular risk factors, such as high blood pressure, overweight or obesity, raised blood sugars and lipids. Some of the documents presented in this manuscript suggest that complying with cardivascular prevention measures may also, at the same time, reduce the risk of other diseases.
Online Informative and Educational Resources on the Benefits That a Lifestyle Aimed at the Primary Prevention of Cancer May Also Provide for General Health  [PDF]
Aldo T. Marrocco
E-Health Telecommunication Systems and Networks (ETSN) , 2015, DOI: 10.4236/etsn.2015.42003
Abstract: To find stimuli for getting young students interested in the primary prevention of cancer and a healthy lifestyle, internet resources have been searched that may motivate and facilitate this study. Teachers interested in teaching this subject can download for free and use them with the method felt as most appropriate; they consist of text, graphs, tables, images, quizzes and an interactive atlas. According to a personal experience, the use of these educational resources helps teachers in teaching and students in learning about cancer prevention. According to the World Health Organisation, cancer is a leading and growing cause of mortality with 10 and 14 million new cases worldwide respectively in 2000 and 2012. Several risk factors have been identified; if they are avoided, more than 30% of the cancers can be prevented. The five most important modifiable risk factors, among many others, are: smoking, alcohol, overweight, physical inactivity, low consumption of vegetables and fruit. Cancer may also have genetic causes or be related to certain infections that are more common in some areas than in others. According to several documents also quoted in this article, numerous behaviours that reduce cancer risk may, at the same time, help to prevent other important diseases. Some of the documents quoted here show the very great difference in cancer incidence and mortality rates often existing between different geographic areas. For example, prostate cancer incidence per 100,000 persons per year is 104.4 in New Zealand, and 3.9 in Chennai, India. Many studies found an increase over time in the incidence of certain cancer types in people that move from countries where their risk is low to countries where their risk is high, thus suggesting the important role of environmental changes and lifestyle. As an example of this, the risk of breast cancer among Hispanic women migrating to US increases with the duration of residence in the immigration country, and becomes up to 4 - 6 times higher after 3 or more generations. This provides an example of what can happen in transitioning countries as a consequence of some lifestyle changes, unless measures are taken.
A Set of GRASS GIS-Based Shell Scripts for the Calculation and Graphical Display of the Main Morphometric Parameters of a River Channel  [PDF]
Aldo Clerici, Susanna Perego
International Journal of Geosciences (IJG) , 2016, DOI: 10.4236/ijg.2016.72011
Abstract: For the analysis of river evolution, the use of quantitative parameters can be quite useful in order to assess changes in the channel planform. Among the several parameters proposed by different authors in a number of papers, channel length and width, braiding and sinuosity indexes, and channel lateral shifting are proved to be the most effective ones for a quantitative analysis of river changes. However, the calculation of these parameters is time-consuming, tedious and error-prone, even where made in a GIS environment. This work describes four shell scripts that perform fast and automatic calculation of the morphometric parameters and draw curves showing thevariation of the calculated parameters along the entire channel development. The scripts arebased on commands of the GRASS GIS free and open source software and, as input, they require a simple vector map containing the essential features of a river channel,i.e.bankfull channel limits and longitudinal and lateral bars.
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