300 research outputs found
Life cycle assessment of a renewable energy system with hydrogen-battery storage for a remote off-grid community
Remote areas usually do not have access to electricity from the national grid. The energy demand is often covered by diesel generators, resulting in high operating costs and significant environmental impacts. With reference to the case study of Ginostra (a village on a small island in the south of Italy), this paper analyses the environmental sustainability of an innovative solution based on Renewable Energy Sources (RES) integrated with a hybrid hydrogen-battery energy storage system. A comparative Life Cycle Assessment (LCA) has been carried out to evaluate if and to what extent the RES-based system could bring environmental improvements compared to the current diesel-based configuration. The results show that the impact of the RES-based system is less than 10% of that of the current diesel-based solution for almost all impact categories (climate change, ozone depletion, photochemical ozone formation, acidification, marine and terrestrial eutrophication and fossil resource use). The renewable solution has slightly higher values only for the following indicators: use of mineral and metal resources, water use and freshwater eutrophication. The climate change category accounts for 0.197 kg CO2 eq./kWh in the renewable scenario and 1.73 kg CO2 eq./kWh in the diesel-based scenario, which corresponds to a reduction in GHG emissions of 89%. By shifting to the RES-based solution, about 6570 t of CO2 equivalent can be saved in 25 years (lifetime of the plant). In conclusion, the hydrogen-battery system could provide a sustainable and reliable alternative for power supply in remote areas
Antimicrobial resistance, an update from the ward: Increased incidence of new potential pathogens and site of infection-specific antibacterial resistances
In order to monitor the spread of antimicrobial resistance, the European Union requires hospitals to be equipped with infection control centers. With this aim, we analyzed 1583 bacterial strains isolated from samples of different origin from patients with community-onset and nosocomial infections in a public tertiary University Hospital on the outskirts of Turin, Italy. Statistical analyses of the isolates (source, type) and their antimicrobial resistance (AMR) were performed. The survey revealed infections associated with bacterial species considered as not-commensal and not-pathogenic, hence potentially emerging as new threats for human health. Conversely to the general observation of nosocomial strains being more resistant to antibiotics compared to community-acquired strains, nosocomial strains isolated in this study were more resistant only to 1/42 tested antibiotics (tetracycline). By adopting an ecological approach, we observed that blood infections are associated with the broadest range of species compared to infections affecting other areas and we obtained clear indications on the antibiotics that should be preferred in the treatment of infections at specific body sites. Future investigations carried out on a larger geographical scale will clarify whether these indications are limited to the geographical region investigated over this study, or whether the same trends are visible at national or international level
Physiological effects of environmental acidification in the deep-sea urchin <i>Strongylocentrotus fragilis</i>
Anthropogenic CO<sub>2</sub> is now reaching depths over 1000 m in the Eastern
Pacific, overlapping the Oxygen Minimum Zone (OMZ). Deep-sea animals are
suspected to be especially sensitive to environmental acidification
associated with global climate change. We have investigated the effects of
elevated <i>p</i>CO<sub>2</sub> and variable O<sub>2</sub> on the deep-sea urchin
<i>Strongylocentrotus fragilis</i>, a species whose range of 200–1200 m
depth includes the OMZ and spans a <i>p</i>CO<sub>2</sub> range of
approx. 600–1200 μatm (approx. pH 7.6 to 7.8). Individuals were
evaluated during two exposure experiments (1-month and 4 month) at control
and three levels of elevated <i>p</i>CO<sub>2</sub> at in situ O<sub>2</sub> levels of
approx. 10% air saturation. A treatment of control <i>p</i>CO<sub>2</sub> at
100% air saturation was also included in experiment two. During the
first experiment, perivisceral coelomic fluid (PCF) acid-base balance was
investigated during a one-month exposure; results show <i>S. fragilis</i>
has limited ability to compensate for the respiratory acidosis brought on by
elevated <i>p</i>CO<sub>2</sub>, due in part to low non-bicarbonate PCF buffering
capacity. During the second experiment, individuals were separated into fed
and fasted experimental groups, and longer-term effects of elevated
<i>p</i>CO<sub>2</sub> and variable O<sub>2</sub> on righting time, feeding, growth, and
gonadosomatic index (GSI) were investigated for both groups. Results suggest
that the acidosis found during experiment one does not directly correlate
with adverse effects during exposure to realistic future <i>p</i>CO<sub>2</sub> levels
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Late miocene/pliocene origin of the inverted metamorphism of the Central Himalaya
The spatial association of intracontinental thrusting and inverted metamorphism, recognized in the Himalaya more than a century ago, has inspired continuing efforts to identify their causal relationship. Perhaps the best known sequence of inverted metamorphism is that found immediately beneath the Himalayan Main Central Thrust (MCT), generally thought to have been active during the Early Miocene. It has been widely assumed that the pattern of inverted metamorphism also developed at that time. Using a new approach, in situ Th-Pb dating of monazite included in garnet, we have discovered that the peak metamorphic recrystallization recorded in the footwall of the MCT fault occurred at ca. 5 Ma. The apparent inverted metamorphism resulted from activation of a broad shear zone beneath the MCT zone which juxtaposed two right-way-up metamorphic sequences. Recognition of this remarkably youthful phase of metamorphism resolves outstanding problems in Himalayan tectonics, such as why the MCT (and not the more recently initiated thrusts) marks the break in slope of the present day mountain range, and transcends others, such as the need for exceptional conditions to explain Himalayan anatexis
Barbed Dental Ti6Al4V Alloy Screw : Design and Bench Testing
Background context. Dental implants are designed to replace a missing tooth. Implant stability is vital to achieving osseointegration and successful implantation. Although there are many implants available on the market, there is room for improvement. Purpose. We describe a new dental implant with improved primary stability features. Study design. Lab bench test studies. Methods. We evaluated the new implant using static and flexion-compression fatigue tests with compression loads, 35 Ncm tightening torque, displacement control, 0.01 mm/s actuator movement speed, and 9-10 Hz load application frequency, obtaining a cyclic load diagram. We applied variable cyclic loadings of predetermined amplitude and recorded the number of cycles until failure. The test ended with implant failure (breakage or permanent deformation) or reaching five million cycles for each load. Results. Mean stiffness was 1151.13 ± 133.62 SD N/mm, mean elastic limit force 463.94 ± 75.03 SD N, and displacement 0.52 ± 0.04 SD mm, at failure force 663.21 ± 54.23 SD N and displacement 1.56 ± 0.18 SD mm, fatigue load limit 132.6 ± 10.4 N, and maximum bending moment 729.3 ± 69.43 mm/N. Conclusions. The implant fatigue limit is satisfactory for incisor and canine teeth and between the values for premolars and molars for healthy patients. The system exceeds five million cycles when subjected to a 132.60 N load, ensuring long-lasting life against loads below the fatigue limit
VALORES HEMATOLÓGICOS Y BIOQUÍMICA RENAL REFERENCIALES DE VENADOS COLA BLANCA (Odocoileus virginianus peruvianus) EN CAUTIVERIO.
The objective of the present study was to determine the normal hematological values and renal biochemistry of the adult white-tailed deer (Odocoileus virginianus) reared in captivity. Blood samples were collected in 25 animals. The deers were anesthetized with two chemical methods of restraint (ketamina 7 mg/kg; ketamina 4 mg/kg and xilacina 1 mg/ kg) without significant difference between both methods in relation to hematological and biochemistry values. In the erythrocytic series, the number of red cells was 10.12 x 106/μl, hemoglobin was 9.5 g/dl, hematocrit was 28.9%, and the erythocytic indexes were VCM = 28.8 fL, HCM = 9.6 pg, CHCM = 33.2 g/dl, without differences due to sex. The number of leukocytes was statistical different (p<0.05) between females (4018 x 103/μl) and males (3059 x 103/μl), but the differential count was similar between sexes (neutrophils: 55.5%, lymphocytes: 39.8%, monocytes: 0.1%, eosinophils: 4.6%). In the renal biochemistry, the mean values for urea and creatinine were 47 mg/dl and 2.1 mg/dl respectively.El objetivo del presente estudio fue determinar el perfil hematológico y bioquímica renal normal del Venado Cola Blanca (Odocoileus virginianus), adulto (1 a 6 años), criado en cautiverio. Se colectaron 25 muestras de sangre de tres zoológicos o zoocriaderos de la zona de Lima. Los animales fueron previamente sedados con dos métodos químicos de contención (ketamina 10 mg/kg y ketamina 4 mg/kg con Xilacina 1 mg/kg), sin que hubiera diferencia significativa entre ambos con relación a los valores hematológicos y bioquímicos. En la serie eritrocítica, el número de glóbulos rojos fue de 10.12 x 106/μl, hemoglobina de 9.5 g/dl, hematocrito de 28.9%, y los índices eritrocíticos fueron de: VCM = 28.8 fL, HCM = 9.6 pg, CHCM = 33.2 g/dl, sin encontrar diferencia entre sexos. En la serie leucocítica, el número de leucocitos fue estadísticamente diferente (p<0.05) entre hembras (4.018 x 103/μl) y machos (3059 x 103/μl), pero sin diferencias en el recuento diferencial (neutrófilos: 55.5%, linfocitos: 39.8%, monocitos: 0.1%, eosinófilos: 4.6%). En la bioquímica renal, el valor de urea fue 47 mg/dl y la creatinina fue de 2.1 mg/dl
Removal of dissolved oxygen interference in the amperometric detection of monochloramine using a pH control method
Monochloramine amperometric determination was investigated using a pH control method to eliminate dissolved oxygen as an interferent. This method allowed local pH conditions to become more acidic, causing the production of dichloramine. This species showed an onset of electro-reduction at 450 mV, far outside of the oxygen reduction region. Monochloramine was calibrated using this method and showed good linearity (0.99) and a limit of detection of 0.03 ppm
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