Optically functional bio-based phase change material nanocapsules for highly efficient conversion of sunlight to heat and thermal storage

Conversion of sunlight to heat and the subsequent thermal storage by nanoencapsulated bio-based phase change material slurries (NBPCMSs) in a low temperature solar system is investigated. The influences of capsule size, shell material, tilt angle, solar heat flux, PCM mass concentration, nanoparticle and its concentration are explored. The results reveal that the useful heat gain capacity of nano-enhanced coconut oil/Ag, coconut oil/Au, coconut oil/Al, and coconut oil/Cu based slurries is respectively 3.02, 3.12, 2.7, and 3.14 times better than that of pure water, due to an enhanced interaction of light with the functional bio-based PCM nanocapsules. Consequently, the thermal energy storage is reported to be 8.85, 9.29, 7.41, and 9.19 times higher. The increment in mass concentration of PCM from 5 to 20 % and addition of blended nanoparticles further augment the solar thermal energy storage capacity. Specifically, the storage capacity of coconut oil/Au based slurry is improved by up to 74.4 % when the 20 % coconout oil is used as a core material. The energy storage improvements of Cu and Ag based slurries enhance by 4.04 and 4.87 %, respectively, with the insertion of Au nanoparticles at a volume fraction of 25 ppm. Augmenting the core/shell confinement size, on the other hand, diminishes the surface area to volume ratio, allowing agglomeration of the structures inside the slurry. The performance of solar energy storage decreases as the inclination angle of the storage cavity increases from 0° to 60°, reducing the buoyancy force and particles’ collision. Further, since Al particles have low optical characteristics and thermal conductivity, the thermal performance of coconut oil/Al nanoencapsulated slurry are at the lowest level. Finally, experiment is conducted to validate the specific heat capacity model prediction under various wind speeds, from 1 to 4 m/s, and solar illuminations, from 400 to 1000 W/m2

The Design and Cytotoxic Evaluation of Some 1-Aryl-3- isopropylamino-1-propanone Hydrochlorides towards Human Huh-7 Hepatoma Cells

Cataloged from PDF version of article.A series of 1-aryl-3-isopropylamino-1-propanone hydrochlorides 1 and a related heterocyclic analog 2 as candidate antineoplastic agents were prepared and the rationale for designing these compounds is presented. A specific objective in this study is the discovery of novel compounds possessing growth-inhibiting properties of hepatoma cells. The compounds in series 1 and 2 were prepared and their structures established unequivocally. X-ray crystallography of two representative compounds 1d and 1g were achieved. Over half of the compounds are more potent than 5-fluorouracil which is an established drug used in treating liver cancers. QSAR evaluations and molecular modeling studies were undertaken with a view to detecting some physicochemical parameters which govern cytotoxic potencies. A number of guidelines for amplification of the project have been formulated. A number of Mannich bases displayed greater potency than the reference drug 5-fluorouracil against human Huh-7 hepatoma cells. In particular, 1i emerged as a lead compound possessing 2.8 fold higher activity than that of the reference drug. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Heat transfer characteristics of fluids containing paraffin core-metallic shell nanoencapsulated phase change materials for advanced thermal energy conversion and storage applications

The influence of heat transfer characteristics of fluids filled with paraffin core-metallic shell nanoencapsulated phase change material (PCM) on photothermal conversion and storage in a volumetrically heated solar system is numerically analysed. The results show that nanoencapsulated paraffin/Al, paraffin/Au, paraffin/Ag, and paraffin/Cu filled heat transfer fluids enhance the energy storage by 68, 73, 92 and 86 %, respectively as compared with the water-based Al, Au, Ag and Cu nanofluids. It is found that the phase change slurry (PCS) improves the temperature and storage gain, as the utilization of nanoencapsulated PCM and the rise in PCM mass concentration enhance the solar energy absorption power of the slurry. The maximum enhancement in stored energy is also observed for paraffin/Cu PCM filled slurry for a particle diameter of 15 nm. The enhancement in mass concentration of paraffin from 5 to 20 %, improves the thermal performance from 312 to 554 % compared to pure water, respectively. Increasing the size of the core/shell architecture of the PCM, however, reduces the surface area-to-volume ratio of the capsule, causing aggregation of the particles and decreasing the heat transfer between the capsule and the host fluid. This in turn results in decrease in temperature gain. Furthermore, it is noticed that the merger of mono- and hybrid- nanoparticles augments the thermal performance of the PCS. The findings of the study indicate that the paraffin core-metallic shell nanoencapsulated PCMs would significantly enhance the performance of advanced photothermal energy conversion and storage devices

Enhanced sensible heat storage capacity of nanofluids by improving the photothermal conversion performance with direct radiative absorption of solar energy

The paper numerically investigates the fluid flow and radiative heat transfer behaviour of water-based mono and hybrid nanofluids in a direct absorption solar collector under solar irradiation boundary conditions. The effects of radiation on the heat and flow performance with operating parameters such as the type of nanoparticles, volume concentrations of nanoparticles, nanoparticle size and type of base fluids are investigated. The numerical results reveal that uniform temperature distribution is obtained with an incident radiation of 1029.81 W/m2 and that the collector performance increases with the addition of nanoparticles owing to their higher radiative properties. While the temperature gain for pure water is 5.58 K, it is estimated to be 48.72 K and 51.32 K with the volume concentrations of 70 ppm and 100 ppm for Al+Al2O3 and Al+Graphite nanofluids, respectively. Moreover, the thermal performance of the collector is positively affected by increasing the size of nanoparticle. For example, for Al+Al2O3 nanofluids at 10 ppm volume concentration, the temperature increase is 37.12 K and 42.02 K at 10 nm and 50 nm, respectively. Therefore, hybrid nanofluids can be considered as effective heat transfer fluids to increase the solar radiation absorbability, and subsequently, improve the efficiency and performance of the direct absorption solar collector

Sensible heat thermal energy storage performance of mono and blended nanofluids in a free convective-radiation inclined system

The photothermal conversion performance (PCP) of a nanofluid-based solar energy system is investigated numerically and experimentally. The impacts of particle size, volume concentration, nanoparticle type, base fluid type and collector inclination angle on the PCP are investigated. It is observed that using nanoparticles improves the ability to absorb solar energy. Temperature gain is 2.2, 3.2, 3.8, 4.2, and 9 times better than pure water for water-based Al, Al2O3, Au, Cu, and Graphite mono nanofluids, respectively. Interestingly, blended nanofluids containing the same nanoparticles significantly argument the optical properties, with useful heat enhancement ranging from 62.8 (mono) to 194 kJ/kg (hybrid). However, the collector's inclination angle, which ranges from 0 to 60°, has a negative impact on the PCP by reducing the solar radiation absorption of the nanofluids due to a decrease in the radiation penetrating the collector. Furthermore, as nanoparticle size increases, so does the thermal performance of the nanofluid. An experimental investigation is carried out for pure water and nanofluid at various wind speeds and solar irradiation levels ranging from 1 to 4 m/s and 200–1000 W/m2, respectively, to validate the numerical results

Child health promotion in underserved communities: The FAMILIA trial

Background: Preschool-based interventions offer promise to instill healthy behaviors in children, which can be a strategy to reduce the burden of cardiovascular disease later. However, their efficacy in underserved communities is not well established. Objectives: The purpose of this study was to assess the impact of a preschool-based health promotion educational intervention in an underserved community. Methods: This cluster-randomized controlled study involved 15 Head Start preschools in Harlem, New York. Schools and their children were randomized 3:2 to receive either a 4-month (50 h) educational intervention to instill healthy behaviors in relation to diet, physical activity, body/heart awareness, and emotion management; or their standard curriculum (control). The primary outcome was the change from baseline in the overall knowledge, attitudes, and habits (KAH) score of the children at 5 months. As secondary outcomes, we evaluated the changes in KAH subcomponents and emotion comprehension. Linear mixed-effects models were used to test for intervention effects. Results: The authors enrolled 562 preschool children age 3 to 5 years, 51% female, 54% Hispanic/Latino, and 37% African-American. Compared with the control group, the mean relative change from baseline in the overall KAH score was ∼2.2 fold higher in the intervention group (average absolute difference of 2.86 points; 95% confidence interval: 0.58 to 5.14; p = 0.014). The maximal effect was observed in children who received >75% of the curriculum. Physical activity and body/heart awareness components, and knowledge and attitudes domains, were the main drivers of the effect (p values <0.05). Changes in emotion comprehension trended toward favoring intervened children. Conclusions: This multidimensional school-based educational intervention may be an effective strategy for establishing healthy behaviors among preschoolers from a diverse and socioeconomically disadvantaged community. Early primordial prevention strategies may contribute to reducing the global burden of cardiovascular disease. (Family-Based Approach in a Minority Community Integrating Systems-Biology for Promotion of Health [FAMILIAThis study is funded by the American Heart Association under grant No. 14SFRN20490315. The CNIC is supported by the Ministerio de Ciencia, Innovación y Universidades and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (SEV-2015-0505). Dr. Fernandez-Jimenez is a recipient of funding from the European Union Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 707642. Dr. Bansilal is an employee of Bayer Pharmaceutical

Different Lifestyle Interventions in Adults From Underserved Communities: The FAMILIA Trial

BACKGROUND: The current trends of unhealthy lifestyle behaviors in underserved communities are disturbing. Thus, effective health promotion strategies constitute an unmet need. OBJECTIVES: The purpose of this study was to assess the impact of 2 different lifestyle interventions on parents/caregivers of children attending preschools in a socioeconomically disadvantaged community. METHODS: The FAMILIA (Family-Based Approach in a Minority Community Integrating Systems-Biology for Promotion of Health) study is a cluster-randomized trial involving 15 Head Start preschools in Harlem, New York. Schools, and their children's parents/caregivers, were randomized to receive either an "individual-focused" or "peer-to-peer-based" lifestyle intervention program for 12 months or control. The primary outcome was the change from baseline to 12 months in a composite health score related to blood pressure, exercise, weight, alimentation, and tobacco (Fuster-BEWAT Score [FBS]), ranging from 0 to 15 (ideal health = 15). To assess the sustainability of the intervention, this study evaluated the change of FBS at 24 months. Main pre-specified secondary outcomes included changes in FBS subcomponents and the effect of the knowledge of presence of atherosclerosis as assessed by bilateral carotid/femoral vascular ultrasound. Mixed-effects models were used to test for intervention effects. RESULTS: A total of 635 parents/caregivers were enrolled: mean age 38 ± 11 years, 83% women, 57% Hispanic/Latino, 31% African American, and a baseline FBS of 9.3 ± 2.4 points. The mean within-group change in FBS from baseline to 12 months was ∼0.20 points in all groups, with no overall between-group differences. However, high-adherence participants to the intervention exhibited a greater change in FBS than their low-adherence counterparts: 0.30 points (95% confidence interval: 0.03 to 0.57; p = 0.027) versus 0.00 points (95% confidence interval: -0.43 to 0.43; p = 1.0), respectively. Furthermore, the knowledge by the participant of the presence of atherosclerosis significantly boosted the intervention effects. Similar results were sustained at 24 months. CONCLUSIONS: Although overall significant differences were not observed between intervention and control groups, the FAMILIA trial highlights that high adherence rates to lifestyle interventions may improve health outcomes. It also suggests a potential contributory role of the presentation of atherosclerosis pictures, providing helpful information to improve future lifestyle interventions in adults.AGENCIA FINANCIADORA: The American Heart Association, under grant No 14SFRN20490315, funded this study. R.F-J is a recipient of funding from the European Union Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 707642. The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia, Innovación y Universidades (MCNU) and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (SEV-2015-0505).S