Estudio técnico-económico de una planta desaladora de agua de mar por ósmosis inversa

En el següent escrit: Estudi técnic-económic d’una planta desaladora d’aigua de mar per osmosis inversa, es pretén donar al lector una idea del procés d’Osmosis Inversa; el qual, ja el podríem ubicar dins dels processos de separació per membranes. Es pretén que aquesta idea sigui el més pràctica possible, sense deixar de banda els aspectes teòrics corresponents, però descartant aquells que, encara tenir relativa importància, l’únic que se aconseguiria amb el seu estudi, seria ampliar el contingut de l’anomenat projecte sense aportarnos això cap benefici relacionat amb l’essència del tema, com es la desalació d’aigua de mar per osmosis inversa. Es per aquest motiu que l’estudi que segueix, es divideix en cinc volums. El primer recull tots els aspectes teórico-práctics, on el lector pot trobar els diferents processos de separació per membranes, les consideracions sobre l’aigua i tot el relacionat amb el fonament fisico-químic que ens pertoca, o sia, la ósmosis inversa: definicions, conceptes bàsics, procés, membranes, etc. L’aspecte pràctic al que ens referim ve reflexat en petits sub-apartats, tals com: neteja eficaç de les membranes, o en seccions posteriors, en petits apartats on es donen recomanacions pràctiques, de instal•lació i inclòs de fabricació d’aparells per postratament. El volum segon és una descripció detalla de l’instal•lació, on s’estudia des de la presa d’aigua de mar fins l’obtenció d’aigua producte, nomenant-se tots els equips, vàlvules, bombes, filtres, etc., que l’aigua travessa en el seu procés. Els tres volums restants corresponen al aspecte més tècnic, on es mostren, por ordre: càlculs, plànols i pressupost o memòria econòmica

Prevalence of undernutrition among pregnant women and its differences across relevant subgroups in rural Ethiopia: a community-based cross-sectional study

Background - Maternal undernutrition is one of the commonest public health problems in many low- and middle-income countries where generally more than 20% of women are undernourished. It is more common in rural areas due to unclear factors. Therefore, the aim of this study was to investigate the prevalence of undernutrition in general and in subgroups and determine risk factors among pregnant women in rural Ethiopia. Methods - A community-based cross-sectional survey was conducted from April 30 to May 30, 2019 on 550 pregnant women who were randomly selected from six districts in southern Ethiopia. Trained and experienced nurses measured undernutrition using mid-upper arm circumference and collected other data. We used multilevel mixed-effect logistic regression to identify factors associated with undernutrition among pregnant women. Results - The prevalence of undernutrition among pregnant women was 38% (95% CI: (34.2–42.3). The odds of undernutrition was higher among women who got pregnant previously (adjusted odds ratio [AOR]: 1.66; 95% CI: 1.02–2.71), who had a history of miscarriage (AOR: 3.18; 95% CI: 1.77–5.70), who practiced food taboos (AOR: 2.23; 95% CI: 1.47–3.39), and who did not get any nutritional counseling during pregnancy (AOR: 2.97; 95% CI: 1.79- 4.95). The prevalence of undernutrition was higher among pregnant women who had multiple risk factors and the difference was statistically significant (p  Conclusion - Undernutrition is a highly prevalent problem among rural Ethiopian pregnant women, especially with those who avoid food, do not get counseled, and had two or more pregnancies and a history of miscarriage. Improving the integration of nutrition programs with routine healthcare services and encouraging a multi-sectorial intervention strategy would help to reduce maternal undernutrition in the country

Heat transfer and hydraulic stability in boiling-water reactors

Fundamental work on heat removal by bubble formation and by increased heat diffusivity as a result of increased turbulence in boundary layers is described. A math. model was constructed of the heat transfer loop that is in operation under pressures up to 40 atm. at input powers up to 600 kw., and inlet subcooling up to 40 Deg. The model is compared with the exptl. results obtained from the loop. The on-set of flow instability is studied, and the nature of the instabilities is characterized in the region up to burnout by means of analysis of power d. curves. The dynamic characteristics of the loop are studied by means of transfer function analysis. The validity of the underlying linearization is discussed and the resulting transfer functions are compared with those obtained from noise analysis. Systematic burnout studies of rod bundles are reported, including the analysis of flow instability preceding burnou

Predictors of exacerbations of asthma and COPD during one year in primary care

Aims. To investigate the incidence of asthma and chronic obstructive pulmonary disease (COPD) exacerbations in primary care during one year and to identify risk factors for such events. Methods. The study was carried out at seven general practice offices in Norway. Patients aged 40 years or more registered with a diagnosis of asthma and/or COPD the previous 5 years were included. After a baseline examination, the participants consulted their GP during exacerbations for the following 12 months. A questionnaire on exacerbations during the follow-up year was distributed to all. Univariable and multivariable logistic regression was performed to determine predictors of future exacerbations. Results. Three hundred and eighty patients attended the baseline examination and complete follow-up data were retrieved from 340 patients. COPD as defined by forced expiratory volume in the first second of expiration/forced vital capacity (FEV1 /FVC) < 0.7, was found in 132 (38.8%) patients. One hundred and fifty-nine patients (46.8%) experienced one exacerbation or more and 101 (29.7%) two exacerbations or more. Patients who had an exacerbation treated with antibiotics or systemic corticosteroids or leading to hospitalization the year before baseline (N = 88) had the highest risk of getting an exacerbation during the subsequent year (odds ratio 9.2), whether the FEV1 /FVC was below 0.7 or not. Increased risk of future exacerbations was also related to age ≥ 65 years and limitations in social activities, but not to the FEV1 . Conclusions. The study confirms that previous exacerbations strongly predict future exacerbations in patients with COPD or asthma. Identification and a closer follow-up of patients at risk of such events could promote earlier treatment when necessary and prevent a rapid deterioration of their condition

Physical activity and survival in chronic comorbidity among adult HIV patients in Ethiopia: a prospective cohort study

Background - Antiretroviral therapy enables people living with HIV to live long lives, and these advances have transformed HIV infection from an acute to a chronic disease. Many non-communicable diseases, including type 2 diabetes, heart disease, and stroke, are influenced by physical inactivity. Therefore, the aim of this study was to assess the level of physical activity and survival in chronic co-morbidity among adult people living with HIV in Ethiopia. Methods - An institution-based prospective cohort study of adult people living with HIV was conducted between 2019 and 2021. We included 422 people living with HIV at baseline. After the baseline visit, 364 patients without hypertension or diabetes, were followed up for two years. Nine trained nurses used a pre-tested, structured questionnaire to collect data during routine care consultations in three hospitals in southern Ethiopia. STATA version 15 was used to analyze the data. To estimate the survival probability of developing chronic comorbidities, a Kaplan-Meier survival curve was used. A Cox proportional hazards model was fitted to identify the predictors of the development of chronic comorbidities. Result - In the current study, 39% of the participants were found to have a low level of physical activity. Those who had self-management skills to maintain physical activity (p = 0.023), considered physical activity an important aspect of their HIV management (p = 0.003), and regularly attended social support groups (p = 0.002) had significantly higher levels of physical activity. The risk of chronic comorbidity increased over time, with a rate of 10.83 chronic comorbidities per 1000 persons per month. Lack of regular exercise [AHR: 2.04; 95% CI: (1.03, 5.13)], low physical activity [AHR: 2.01; 95% CI: (1.03, 7.89)], BMI greater than 25 kg/m2 [AHR: 2.74; 95% CI: (1.31, 5.12)] and low fruit and vegetable intake [AHR = 2.57; 95% CI: (1.28, 6.49)] were all associated with the development of chronic comorbidity. Conclusion - The prevalence of physical inactivity is high in the study population. A physical activity program for people living with HIV should be considered, and the promotion of self-management skills should be integrated into HIV care programs