This work aimed to incorporate the active compounds of the jambolan leaf in sunflower seed oil, in order to increase the nutritional quality of the oil. For this purpose, ultrasound-assisted extraction was conducted to establish the process conditions related to temperature, potency, solvent:sample ratio and time to obtain the enriched sunflower seed oil (ESSO). An experimental design was applied to examine the effect of variables (temperature, power, solvent:sample ratio and time) on the extraction mass yield (EMY). The application of maximum temperature, increased power, sample:solvent ratio and time resulted in higher EMY. Maximum theoretical EMY value was 35.16% (60 °C, 100%, 1:12 g mL-1 and 15 min). The characterization of the oils obtained from ESSO and sunflower seed oil (SSO) verified a higher content of flavonoids, phenolic compounds, a large proportion of active compounds, antioxidant activity, content of phytosterols, α-tocopherol and squalene, and induction time for ESSO. purpose ultrasoundassisted ultrasound assisted temperature potency solventsample solvent sample . (ESSO) (temperature power (EMY) samplesolvent 3516 35 16 35.16 60 (6 C °C 100 100% 112 1 12 1:1 mL1 mL mL- min. min min) SSO (SSO flavonoids activity phytosterols αtocopherol α tocopherol squalene (ESSO (EMY 351 3 35.1 6 ( 10 11 1: 35.

The recycle and utilization of expired drugs is a challenge for many countries at present. The employment of expired drugs as green corrosion inhibitors is expected to address both drug recycling and corrosion prevention issues, with significant economic and environmental value. Herein, the individually and combination corrosion inhibition performance of expired amoxicillin (AMC) and penicillin V potassium tablets (PVP) for lowcarbon steel in 20% acetic acid solution containing 600 mg L-1 chloride ion are evaluated by electrochemistry and weight loss method. Both the AMC and PVP present the mixed-type corrosion inhibitors mainly affect the cathode process when used individually. The optimum inhibition efficiency is 61.22% (AMC) and 79.21% (PVP), which all appear in 5.0 × 10-3 mol L-1. The AMC and PVP are adsorbed on the steel surface by mixed physisorption and chemisorption, which are consistent with the Langmuir adsorption isotherm. The corrosion inhibition rate drops sharply when AMC and PVP are combined use with a close mole ratio. But a small amount of PVP significantly enhance the corrosion inhibition effect of AMC, the corrosion inhibition rate from 61.22 to 79.72%. The corrosion inhibition rate of AMC and PVP combination inhibitor decreased with the increase of temperature. issues value Herein (AMC (PVP 20 60 L1 L 1 L- method mixedtype type 6122 61 22 7921 79 21 79.21 PVP, , 50 5 0 5. 103 10 3 10- L1. 1. chemisorption isotherm ratio 61.2 7972 72 79.72% temperature 2 6 612 792 7 79.2 61. 797 79.72 79. 79.7

Silver film is commonly used to examine the structure and composition of molecules due to its surface-enhanced Raman scattering (SERS) effect. A simple method for preparing SERS silver films is proposed in this paper by electrodeposition in an amide-based liquid mixture (urea-acetamide-LiBr). The electrochemical behavior of silver in urea-acetamide-LiBr mixture was studied by cyclic voltammetry (CV) and chronoamperometry. It was found that the nucleation mechanism of silver shifts to instantaneous nucleation under diffusion control with increasing overpotential and temperature. The energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) investigations confirmed that the obtained deposits are pure silver. Scanning electron microscopy (SEM) analysis showed that the morphology of the silver deposits depends on the deposition potential and temperature. Rhodamine 6G was used as probe molecules for SERS experiments, showing that these new active substrates have high sensitivity to SERS response with high enhancement factors, of approximately 107, and enable Raman scattering even for diluted solutions. surfaceenhanced surface enhanced (SERS effect amidebased amide based ureaacetamideLiBr. ureaacetamideLiBr urea acetamide LiBr . (urea-acetamide-LiBr) CV (CV chronoamperometry temperature EDS (EDS Xray X ray XRD (XRD SEM (SEM G experiments factors 107 solutions (urea-acetamide-LiBr 10 1

ABSTRACT Desertification is the degradation process caused by climatic conditions and human activities that results in loss of soil productivity and decline in vegetation growth in the long term. Several indices related to vegetation, soil and climate are used to monitor desertification, but few studies explore qualitative and quantitative aspects of indices on desertification on spatial and hierarchical scale. This study aims to identify and measure indices related to increased risk of desertification on global, local and hierarchical scales using multinomial logistic regression models. Images from TM, ETM+ and OLI sensor from 1997 to 2018 in the end of dry and rainy seasons were used to quantify NDVI, TGSI, albedo, temperature, aridity index, evapotranspiration and precipitation on global spatial scale (Irauçuba Centro Norte) and local spatial scale (Miraíma, Canindé, Irauçuba and Santa Quitéria). GISD was calculated by geometric mean of weighted indices and segmented into 8 classes of susceptibility to desertification (hierarchical scale). The results showed that the best models were obtained on local scale and for the end of the rainy season. Temperature proved to be the most important variable for increased risk of desertification on global, local and hierarchical scales. Therefore, the increase in the risk of desertification in the studied areas is due to human activities of deforestation, overgrazing and fire. These factors contributed to reduction of vegetation cover and increase in temperature, changing the microclimatic, which led to decline in precipitation and worsening of desertification. term TM ETM 199 201 NDVI TGSI albedo temperature index Norte Miraíma, Miraíma (Miraíma Canindé Quitéria. Quitéria . Quitéria) scale) season Therefore deforestation fire microclimatic 19 20 1 2

Abstract This study aimed to evaluate the effect of thermal treatment on the adhesion quality of bonded joints in high-density wood, specifically Corymbia citriodora and Eucalyptus pellita, using resorcinol formaldehyde and castor oil-based polyurethane adhesives. It was used at temperatures of 160 ºC, 180 ºC and 200 °C, being compared with a control batch. The percentage of failure in the wood was analyzed to evaluate the quality of the bonding. The castor oil-based polyurethane adhesive exhibited higher values of viscosity and solid content than resorcinol formaldehyde. Eucalyptus pellita showed higher shear strength values compared to Corymbia citriodora wood. The increase in temperature reduced the shear strength for both woods. The ratio between the strength of the bonded wood and solid wood, at the same treatment temperature, often exceeded one, indicating the formation of an adhesive-fiber composite, which enhances the strength of the bonded interface, especially for C. citriodora wood. Overall, there was better bonding of Eucalyptus pellita wood with resorcinol formaldehyde, and it exhibited less thermal degradation due to lower mass loss. highdensity high density oilbased oil based adhesives 16 18 20 C °C batch woods one adhesivefiber fiber composite interface Overall loss 1 2

Resumo Esse estudo teve como objetivo avaliar o efeito do tratamento térmico na qualidade da adesão de juntas coladas de madeira de alta densidade, Corymbia citriodora e Eucalyptus pellita utilizando os adesivos resorcinol e poliuretano vegetal à base de óleo de mamona. O tratamento térmico foi realizado nas temperaturas de 160 ºC, 180 ºC e 200 °C, sendo comparadas com um lote controle. A qualidade da colagem foi avaliada através do teste de cisalhamento e análise do percentual de falha na madeira. O adesivo de poliuretano de mamona apresentou maiores valores de viscosidade e teor de sólidos, do que o resorcinol formaldeído. O Eucalyptus pellitaexibiu maiores valores de resistência ao cisalhamento que a madeira de Corymbia citriodora. O aumento da temperatura reduziu a resistência ao cisalhamento para ambas as madeiras. A razão entre a resistência da madeira colada com madeira solida, na mesma temperatura de tratamento, muitas vezes atingiu valores superiores a um, indicando a formação de um compósito adesivo-fibras, que aumenta a resistência da interface colada, especialmente para madeira de C. citriodora. De forma geral, houve uma melhor colagem da madeira de Eucalyptus pellita, com resorcinol formaldeído, e está exibiu menor degradação térmica, devido à menor perda de massa. densidade 16 18 20 C °C controle sólidos formaldeído madeiras solida adesivofibras, adesivofibras fibras, fibras adesivo-fibras geral térmica massa 1 2

Resumo O concreto quando exposto a elevadas temperaturas tem suas propriedades alteradas e os processos de recuperação são dependentes da intensidade destas modificações. O objetivo deste artigo foi avaliar a influência das altas temperaturas nas propriedades do concreto, em uma faixa na qual a estrutura ainda pode ser recuperada, e a verificação dos efeitos gerados no material quando submetidos a resfriamento natural e resfriamento rápido. Para isto se desenvolveu o programa experimental com três traços de concreto, os quais foram expostos a temperaturas de 100 ºC, 300 ºC, 450 ºC e 600 ºC; subdivididos em grupos de resfriamento lento e rápido. Com a elevação da temperatura, intensificam-se os processos de fissuração e alterações microestruturais, as quais geram redução nas resistências mecânicas e o aumento da absorção. Verificou-se que o módulo de elasticidade foi a propriedade mais afetada por estas alterações. As correlações entre o módulo de elasticidade e as demais propriedades foram acompanhadas pelo aumento da microfissuração do concreto, perda de água e decomposição das fases da pasta, sendo observada posterior reidratação da etringita durante o resfriamento do concreto. modificações recuperada rápido 10 30 45 60 temperatura intensificamse intensificam microestruturais absorção Verificouse Verificou pasta 1 3 4 6

Abstract Concrete, when exposed to high temperatures, has its properties changed, and the recovery processes depend on the intensity of these changes. This paper aimed to evaluate the influence of high temperatures on concrete properties and verify the effects generated in the material when submitted to natural and fast cooling. Three different concrete mixes were exposed to temperatures of 100 °C, 300 ºC, 450 ºC, and 600 ºC, subdivided into slow and fast cooling groups. With the increase in temperature, cracking processes and microstructural alterations intensified, generating reductions in mechanical strength and increases in absorptions. This study has identified that the elastic modulus was the property most affected by these changes. The correlations between the elastic modulus and the other properties were accompanied by increased concrete micro-cracking, water loss, and decomposition of paste phases. Also, it was found an effect of ettringite rehydration during concrete cooling. Concrete changed changes 10 C °C 30 ºC 45 60 groups temperature intensified absorptions microcracking, microcracking micro cracking, micro-cracking loss phases Also 1 3 4 6

Resumen: Las Reservas Ecológicas, son la base primordial para la subsistencia de la biodiversidad, desempeñan funciones cruciales para el mantenimiento de los ecosistemas, especialmente, en la preservación de los servicios ecosistémicos de regulación del clima y suministro de agua. Determinar la capacidad de acumulación del COS en tres ecosistemas de la Reserva Ecológica Arenillas (REAR) y la influencia que tienen con los factores de profundidad y el tipo de suelo, fue el objetivo de la investigación. Se partió de la hipótesis que dichos factores ejercen un efecto sobre las propiedades físicas-químicas del suelo, provocando la variabilidad del carbono. Se establecieron 14 unidades de muestreo para los tres ecosistemas; 1) Intervenido, 2) Bosque deciduo y 3) Bosque arbustal deciduo, se extrajo de cada unidad dos muestras de suelo a profundidades de (0-10 y 10-30 cm), dando un total de 28 muestras. Los resultados revelaron diferencias significativas entre los tres tipos de ecosistemas, permitiendo afirmar que, en la REAR, el contenido de COS es mayor en el ecosistema de Bosque deciduo, que en los denominados Bosque arbustal deciduo y la zona Intervenida. Así mismo, los suelos del tipo Alfisol y Entisol en el Bosque deciduo presentaron la mayor capacidad de almacenamiento de COS, siendo la capa superficial la de mayor acumulación en los tres ecosistemas. Se concluyó que las bajas precipitaciones, el aumento de la temperatura y la esporádica vegetación producida por actividades antrópicas, afectan el almacenamiento de COS, limitando la prestación de servicios ecosistémicos relacionados con la captura de carbono edáfico.

Abstract: Ecological Reserves are the primary basis for the subsistence of biodiversity, they play crucial roles in the maintenance of ecosystems, especially in the preservation of ecosystem services of climate regulation and water supply. The objective of the research was to determine the accumulation capacity of COS in three ecosystems of the Arenillas Ecological Reserve (REAR) and the influence of depth factors and soil type. It was hypothesized that these factors exert an effect on the physical-chemical properties of the soil, causing carbon variability. Fourteen sampling units were established for the three ecosystems; 1) Intervened, 2) Deciduous Forest and 3) Deciduous shrub forest, two soil samples were extracted from each unit at depths of (0-10 and 10-30 cm), giving a total of 28 samples. The results revealed significant differences between the three types of ecosystems, allowing us to affirm that, in the REAR, the COS content is higher in the deciduous forest ecosystem than in the deciduous shrub forest and the Intermediate zone. Likewise, Alfisol and Entisol soils in the deciduous forest had the highest COS storage capacity, being the surface layer the one with the highest accumulation in the three ecosystems. It was concluded that low precipitation, increased temperature and sporadic vegetation produced by anthropic activities affect COS storage, limiting the provision of ecosystem services related to soil carbon sequestration.

Resumen El retroceso de los glaciares es una realidad en toda la cordillera de los Andes, sobre todo en montañas de baja altitud. Uno de estos casos es la pérdida de la masa de hielo remanente en el Carihuairazo (Tungurahua, Ecuador), que en los últimos años ha experimentado un retroceso considerable. En esta investigación se intenta caracterizar el retroceso de este glaciar y su implicación en la comunidad más cercana (Cunucyacu) por medio de la aplicación de una metodología de múltiples fuentes que incluye la recopilación de aerofotografías del glaciar, datos de estaciones meteorológicas cercanas, uso de datos de reanálisis del clima global, entrevistas a miembros de la comunidad y a andinistas que trabajan y frecuentan la zona. Para caracterizar la evolución de la masa del glaciar aplicamos un modelo hidroglaciológico que usa como entrada datos de series meteorológicas y cuyos parámetros fueron calibrados con el registro fotográfico del contorno del glaciar. Como resultados se puede evidenciar una pérdida del glaciar para el 2021 equivalente al 99% de su superficie en 1956 (0.34 km 2). El modelo logra simular la variación del área del glaciar durante 67 años, en donde se observa un decrecimiento continuo del glaciar a partir de 1978, con cortos periodos de recuperación y equilibrio, en donde la temperatura es la variable que mejor explica el retroceso del glaciar. El modelo no logra considerar el efecto de factores externos como el caso de la erupción del volcán Tungurahua que podría favorecer el retroceso del glaciar. El glaciar Carihuairazo se encuentra en una situación de inevitable desaparición y revela las vulnerabilidades de las comunidades que se enfrentan a este fenómeno como consecuencia del cambio climático.

Abstract The retreat of glaciers is a reality throughout the Andes Mountain range, especially in low-altitude mountains. One of these cases is the loss of the remaining ice mass in Carihuairazo (Tungurahua, Ecuador), which in recent years has experienced a considerable retreat. This research aims to characterize the retreat of this glacier and its implications for the nearby community (Cunucyacu) through the application of a multi-source methodology, which includes the collection of glacier aerial photographs, data from nearby meteorological stations, the use of global climate reanalysis data, interviews with community members, and mountaineers who work and frequent the area. To characterize the glacier’s mass evolution, a hydroglaciological model was applied, using input data from meteorological series, and its parameters were calibrated with the photographic record of the glacier’s outline. The results show a glacier loss of 99% of its surface in 1956 (0.34 km 2) by 2021. The model successfully simulates the glacier area variation over 67 years, revealing a continuous decrease since 1978, with short periods of recovery and equilibrium, where temperature is the variable that best explains the glacier’s retreat. However, the model fails to consider the effect of external factors, such as the eruption of the Tungurahua volcano that could enhance the glacier retreat. The Carihuairazo glacier is in a situation of inevitable disappearance, highlighting the vulnerabilities of communities facing this phenomenon as a consequence of climate change.

ABSTRACT The results of the effect of five different incubation temperatures on the development of clownfish (Amphiprion ocellaris) larvae are presented. This ornamental species is widely marketed worldwide and is reared in captivity at CIAD to meet the demand in the domestic market. The experimental work was carried out over 30 days post-hatching to observe the temperature's effect on the development of the larvae's vertebral column and caudal complex. The eggs were incubated at 26, 28, 30, 32, and 34°C. The percentage of hatching, survival, growth, and the presence of skeletal malformations were evaluated. Hatching and survival percentages did not show significant differences between treatments. Regarding growth, there were significant differences between treatments, with organisms showing slower growth at 26°C and larger sizes at 34°C. The highest percentage of malformations occurred in larvae cultured at 34°C, with lordosis being the most frequently observed deformity among the treatments. Therefore, it can be concluded that the optimal temperature range for cultivating and harvesting quality A. ocellaris organisms is between 28 and 30°C.

ABSTRACT A stochastic model was developed to analyze Crassostrea virginica production when cultivated at three stocking densities, defined as the area occupation (50, 75, and 100%) in Nestier-type trays, using juvenile oysters with an initial size (height) of 29.40 ± 0.18 mm. A 25-week grow-out was first conducted in the Rio Lagartos lagoon, showing that final oyster size was inversely related to density (P < 0.05), ranging from 61.87 mm (100% density) to 68.00 mm (50% density). At the same time, mortality was negligible (lower than 1.0%). The environmental conditions in the lagoon were stable, and the oyster growth rate positively correlated with water temperature and pH. Low pH was associated with slow oyster growth, possibly as an adverse effect of acidic conditions on the oyster shell formation. The model indicated that, for an initial 100,000 oyster population, the maximum production (oyster dozens) is obtained after 20 weeks (8310 at 50% density) and 25 weeks (8250 at 75%, and 6670 at 100% density). There was a 100% probability of oysters reaching a minimum commercial size (MCS) of 60.00 mm when using the 50 and 75% densities and 80.6% when using 100%. The model estimated that, for the maximum density, extending the grow-out up to 32 weeks would allow reaching MCS with 100% probability, although this should be experimentally confirmed. The random variability of oyster production in 50 and 75% densities was minimal, while at 100% density, it was extremely high. A sensitivity analysis indicated that for 50 and 75% densities, the main stochastic elements influencing production, are related to oyster mortality, while at 100% density, they are related to oyster growth.

ABSTRACT Marine pollution caused by microplastics (MPs) in the ocean has been very high research in recent years, and their effects over different marine organisms such as zooplankton have been recognized. The crescent literature requires review and harmonization of the methodologies to unify criteria of comparison. Literature on microplastic ingestion in marine organisms is just beginning to be published, so it is of great importance to establish unified techniques for the extraction methodologies of microplastics ingested by zooplankton to determine the abundance and characteristics of MPs. Databases were used to find specific techniques for digestion of organic material from marine organisms, and four specific techniques were chosen for zooplankton degradation. Samples collected at one station in the Corales del Rosario and San Bernardo National Natural Park, Colombia were done. The chosen techniques were evaluated in four aspects: 1) The efficiency of digestions was evaluated on zooplankton samples, 2) The efficiency of digestion different duration and temperature conditions was assessed, 3) Evaluate the effect physics of digestions on microplastics, 4) Quantifying MPs from the ingestion rate. Fifty individuals were chosen from the sample to evaluate each technique. The most abundant groups corresponding to the families Paracalanidae, Corycaedae and Oncaeidae, and the phylum Chaetognatha were used. The best technique obtained was Md Amin et al (2020) with our modifications, this technique uses HNO3 65 % at 80 °C of temperature during one hour, in bottles of 2 mL lid with heat resistant. The organic matter was totally degraded, not changes on the physic integrity of MPs were observed, and the ingestion rates were similarly reported for other authors in these organisms.

RESUMEN Existe un incremento de publicaciones por conocer la problemática de la contaminación marina por microplásticos (MPs), donde ya se reconocen algunos de los efectos que pueden tener en el zooplancton. Este aumento de publicaciones requiere que se revisen las metodologías para unificar criterios de comparación, por lo que es de gran importancia unificar técnicas para las metodologías de extracción de los microplásticos ingeridos por el zooplancton para determinar la abundancia y las características de los MPs. A partir de una búsqueda en bases de datos, se escogieron cuatro técnicas específicas para la degradación de la materia orgánica representada por el zooplancton. Las técnicas fueron evaluadas en cuatro aspectos: 1) Eficiencia de la degradación de la materia orgánica, 2) Duración y condiciones de temperatura para el procesamiento, 3) Efecto físico de la digestión sobre los microplásticos, 4) cuantificar los MPs a partir de la tasa de ingestión. Se emplearon cincuenta individuos para cada uno de los grupos más abundantes correspondientes a las familias Paracalanidae, Corycaeidae y Oncaeidae, y al filo Chaetognatha. Los resultados obtenidos mostraron que la mejor técnica fue la de Md Amin et al (2020) con modificaciones, en la que no se observaron alteraciones en la integridad de los MPs y la tasa de ingestión fue similar a la que se reporta para estos organismos.

Resumen El gasto de energía en proceso es una investigación de vanguardia en el campo general de la aplicación de la energía. En este trabajo se estimó la cantidad de energía para calentar o comprimir un sistema en fase gaseosa utilizando las ecuaciones termodinámicas. En primer lugar, se eligieron los sistemas y entre los alcoholes los usamos de C3 a C12 para discutir el efecto del número de átomos de carbono en la cadena. En segundo lugar, la ecuación de Peng-Robinson representó el comportamiento del sistema pVT. Además, se analizó la influencia del nivel en la temperatura y la presión. Los resultados muestran que la energía gastada para el calentamiento isobárico fue muy similar en valor con respecto al rango de presiones (1-20 atm). El número de carbonos en la cadena tuvo influencia significativa en el resultado de calentamiento de los alcoholes, así como en la solución de integral de pdV. Para la compresión isotérmica, cuando el proceso ocurrió a bajas presiones (1 a 5 atm), la cantidad de energía gastada fue prácticamente constante para todos los alcoholes estudiados. Además, para el mismo rango de presión, a medida que aumenta la temperatura, aumenta la energía para comprimir. Debido a que no hay influencia del término pdV, el cambio de energía interna podría considerarse como el mismo de la energía gastada en el proceso. Las principales conclusiones extraídas de este trabajo serán de gran ayuda para el desarrollo futuro de equipos de eficiencia como los motores de combustión.

Abstract In-process energy expenditure is cutting-edge research in the general field of energy application.In this paper, the amount of energy for heating or compressing a system in gas phase was estimated by using the thermodynamic equations. Firstly, thesystems were chosen and among the alcohols, we used them from C3 to C12 to discussthe effect of number of carbons atoms in the chain. Secondly, the Peng-Robinson equation represented the pVT system behavior. Also, influences of the level in temperature and pressure was analyzed. The results show that the energy expended for isobaric heating was very similar in value regardig the pressure range (1-20 atm).The number of carbons in the chain had significant influence on the heating result of alcohols, as well as in the solution of integral of pdV. For isothermic compression, when the process ocurred at low pressures (1 to 5 atm),the amount of spent energy was pratically constant for all alcohols studied. Furthermore, for the same pressure range, as the temperature increases, the energy required to compress increases.Because there is no influence of the pdV term, internal energy change could be considered as the same of spent energy in the process. The main conclusions drawn from this work will be helpful for future development of of efficient equipment such as combustion engines.

ABSTRACT Agroindustrial potato (Solanum tuberosum L.) waste mainly includes peel and pulp; however, potatoes of low industrial quality are also discarded by industry. A viable alternative to give added value to these byproducts is the use of these as seeds, as well as the use of starch. The objective of this work was to evaluate the physiological quality (germination and vigor), starch content and relationship between these variables in discarded tubers from the industry through chemical-structural analyses to better understand their influence on starch composition. The physiological quality of the potatoes was evaluated through germination and vigor tests; likewise, starch was extracted, and the yield was determined. Physicochemical characterization of the starches was carried out through proximal and structural analysis using nuclear magnetic resonance (NMR). The results showed that the tubers had 100.00% germination and 98.66% vigor and were suitable for use as seeds. The starch yield did not significantly differ. However, characterization of the starch revealed significant differences (p ≤ 0.05) in moisture, ash, carbohydrate and amylose contents, which were influenced by the storage temperature (4 °C) of the tubers subjected to a vigor test, which interferes with enzymatic activity. During germination, the NMR results showed type B crystallinity, which is typical of tubers, indicating that the viability tests did not promote changes in the type of crystallinity. The results obtained can help us understand the effect of germination on the composition of starch and, accordingly, choose the most appropriate applications for this starch, whether food or nonfood.

Resumo O objetivo do trabalho foi comparar o comportamento de elementos climáticos e eventos térmicos extremos entre duas unidades de paisagem da cidade de Neuquén, Argentina, no período de 2013 a 2020. Foram analisados dados diários de temperatura mínima (Tmin), temperatura máxima (Tmax) e umidade relativa (UR) das estações meteorológicas “Neuquén Aero” (NA) e “Paseo de la Costa” (PC), que são referências do vale (área periurbana) e do corredor fluvial (ambiente ribeirinho), respectivamente. Foi analisada a influência da margem nas Tmin e Tmax diárias durante ondas de calor (OC) e ondas de frio (OF) no vale de acordo com a metodologia do Serviço Meteorológico Nacional. As médias de Tmax (Tmin), em resoluções anuais, sazonais e mensais, foram menores (maiores) em PC. Os valores médios de UR foram superiores em NA. Durante as OC, foi observado um efeito regulador em relação à quantidade de dias em que os valores limites foram excedidos de forma consecutiva no litoral fluvial.

Abstract This paper aimed to compare the behavior of climatic elements and extreme thermal events between two landscape units of the city of Neuquén, Argentina, for the period 2013-2020. The study involved daily data of minimum temperature (Tmin), maximum temperature (Tmax), and relative humidity (RH) obtained from the meteorological stations “Neuquén Aero” (NA) and “Paseo de la Costa” (PC), referring to the valley (peri-urban area) and the fluvial corridor (riparian environment) respectively. The influence of the riverbank on the daily Tmin and Tmax during Heat Waves (HW) and Cold Waves (CW) in the valley was analyzed using the methodology of the National Meteorological Service. The mean Tmax (Tmin), at annual, seasonal, and monthly resolutions, were lower (higher) in PC. The mean RH values were higher in NA. During the HW, a regulatory effect was exhibited regarding the number of days that the threshold values were exceeded consecutively in the fluvial littoral.

Resumen El objetivo del trabajo fue comparar el comportamiento de elementos climáticos y eventos térmicos extremos entre dos unidades de paisaje de la ciudad de Neuquén (Argentina) para el período 2013-2020. Se examinaron datos diarios de temperatura mínima -Tmin-, temperatura máxima -Tmax- y humedad relativa -HR- de las estaciones meteorológicas “Neuquén Aero” (NA) y “Paseo de la Costa” (PC), referentes del valle (área periurbana) y del corredor fluvial (entorno ripario) respectivamente. Se analizó la influencia de la ribera en las Tmin y Tmax diarias durante Olas de Calor (OC) y Olas de Frío (OF) en el valle según metodología del Servicio Meteorológico Nacional. Las Tmax (Tmin) medias, a resoluciones anual, estacional y mensual, resultaron menores (mayores) en PC. Los valores medios de HR fueron superiores en NA. Durante las OC, se exhibió un efecto regulador respecto a la cantidad de días que se excedieron los valores umbrales de manera consecutiva en el litoral fluvial.

Abstract The aim of the article was to investigate the impact of vacuum tube joints on the thermosiphon effect. The effect of the tube connections in the solar heater was analyzed using two different height arrangements. These configurations were simulated under the same conditions through software that allowed us to enter data related to the city of Riobamba, which has a low latitude. The first design was made by inserting the vacuum tubes in the middle of the tank, while the second was placed at the bottom of the tank. For the thermal-optical analysis, a solar reflector was used, and the data obtained during the simulation was manipulated. A greater temperature distribution was found in the tank for higher hydrodynamic heights. Acceptable values of useful heat and heat losses were determined. The position of the joints directly influenced the thermosiphon effect since it increased the force with which the water circulated in the tank due to the greater volume of water in this configuration. The heat losses evidenced the need to use another type of cover. However, this model generated enough energy to be used domestically

Resumen El objetivo del artículo fue investigar el impacto de las uniones de los tubos de vacío en el efecto termosifón. Se analizó el efecto de las conexiones de los tubos en el calentador solar empleando dos disposiciones de alturas diferentes. Se simuló dichas configuraciones bajo las mismas condiciones con un software que nos permitió introducir datos relativos a la ciudad de Riobamba, la cual posee una latitud baja. El primer diseño se realizó insertando los tubos de vacío en la mitad del tanque mientras que en el segundo se colocó en el fondo del tanque. Para el análisis térmico-óptico, se empleó un reflector solar y se manipuló los datos obtenidos durante la simulación efectuada. Se encontró en el tanque, una mayor distribución de temperaturas para alturas hidrodinámicas mayores. Se determinaron valores aceptables de calor útil y pérdidas de calor. La posición de las uniones influyó directamente en el efecto termosifón ya que esta aumentaba la fuerza con la que el agua circulaba alrededor del tanque debido al mayor volumen de agua en esta configuración. Las pérdidas de calor evidenciaron la necesidad de emplear otro tipo de cobertor. Sin embargo, este modelo generó suficiente energía para ser empleada de manera doméstica.