Diclofenac sorption from synthetic water: Kinetic and thermodynamic analysis

This work investigated diclofenac sorption on 0.5g L-1 activated carbon in a range of temperature (288-318K) and of initial sorbate concentration (24-218mgL-1). Thermodynamic modelling was carried out with the Langmuir isotherm. For kinetic modelling we compared the so-called Diffusion-Controlled Langmuir Kinetics (DCLK) and the pseudo-second order (PSO) model. The maximum sorption capacity of the sorbent, equal to 180mgg-1, was independent of temperature. Experimental data fitted well with both kinetic models, yet the DCLK model was found to be more informative about the mechanism of the process. Kinetic parameters (α, β) increased with the temperature, with α value rising from 5×10-5 to 20×10-5 L mg-1min-0.5, and β value rising from 3×10-6 to 20×10-6 L mg-1min-1 in the temperature range investigated

Gadolinium-Doped Bismuth Ferrite for the Photocatalytic Oxidation of Arsenite to Arsenate under Visible Light

Arsenic in drinking water is one of the most concerning problems nowadays due to its high toxicity. The aim of this work is the photocatalytic oxidation of As(III) to As(V) under visible light. This study is focused on the use of gadolinium-doped bismuth ferrite as a photocatalyst active under visible light. Different gadolinium amounts were evaluated (0, 0.5, 1, 2, 5, 10 mol%), and 2 mol% resulted in the best gadolinium amount to reach higher photocatalytic efficiency in terms of As(V) production. The samples were thoroughly characterized in their optical, structural, and morphological properties. The results allowed us to identify an optimal concentration of gadolinium equal to 2 mol%. The reactive oxygen species most responsible for the photocatalytic mechanism, evaluated through the addition of radical scavengers, were O-2(-center dot) and e(-). Finally, a photocatalytic test was performed with a drinking water sample polluted by As(III), showing photocatalytic performance similar to distilled water. Therefore, gadolinium-doped bismuth ferrite can be considered an efficient catalytic material for the oxidation of As(III) to As(V) under visible light

Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 105 and 109 GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission

Northrop Grumman TR202 LOX/LH2 Deep Throttling Engine Technology Project Status

NASA's Propulsion and Cryogenic Advanced Development (PCAD) project is currently developing enabling propulsion technologies in support of future lander missions. To meet lander requirements, several technical challenges need to be overcome, one of which is the ability for the descent engine(s) to operate over a deep throttle range with cryogenic propellants. To address this need, PCAD has enlisted Northrop Grumman Aerospace Systems (NGAS) in a technology development effort associated with the TR202 engine. The TR202 is a LOX/LH2 expander cycle engine driven by independent turbopump assemblies and featuring a variable area pintle injector similar to the injector used on the TR200 Apollo Lunar Module Descent Engine (LMDE). Since the Apollo missions, NGAS has continued to mature deep throttling pintle injector technology. The TR202 program has completed two series of pintle injector testing. The first series of testing used ablative thrust chambers and demonstrated igniter operation as well as stable performance at discrete points throughout the designed 10:1 throttle range. The second series was conducted with calorimeter chambers and demonstrated injector performance at discrete points throughout the throttle range as well as chamber heat flow adequate to power an expander cycle design across the throttle range. This paper provides an overview of the TR202 program, describing the different phases and key milestones. It describes how test data was correlated to the engine conceptual design. The test data obtained has created a valuable database for deep throttling cryogenic pintle technology, a technology that is readily scalable in thrust level

Robust Limits from Upcoming Neutrino Telescopes and Implications on Minimal Dark Matter Models

Experimental developments in neutrino telescopes are drastically improving their ability to constrain the annihilation cross-section of dark matter. In this paper, we employ an angular power spectrum analysis method to probe the galactic and extra-galactic dark matter signals with neutrino telescopes. We first derive projections for a next generation of neutrino telescope that is inspired by KM3NeT. We emphasise that such analysis is much less sensitive to the choice of dark matter density profile. Remarkably, the projected sensitivity is improved by more than an order of magnitude with respect to the existing limits obtained by assuming the Burkert dark matter density profile describing the galactic halo. Second, we analyse minimal extensions to the Standard Model that will be maximally probed by the next generation of neutrino telescopes. As benchmark scenarios, we consider Dirac dark matter in $s$- and $t$-channel models with vector and scalar mediators. We follow a global approach by examining all relevant complementary experimental constraints. We find that neutrino telescopes will be able to competitively probe significant portions of parameter space. Interestingly, the anomaly-free $L_{\mu}-L_{\tau}$ model can potentially be explored in regions where the relic abundance is achieved through freeze-out mechanism

Northrop Grumman TR202 LOX/LH2 Deep Throttling Engine Project Status

NASA's Propulsion and Cryogenic Advanced Development (PCAD) project is currently developing enabling propulsion technologies in support of the Exploration Initiative, with a particular focus on the needs of the Altair Project. To meet Altair requirements, several technical challenges need to be overcome, one of which is the ability for the lunar descent engine(s) to operate over a deep throttle range with cryogenic propellants. To address this need, PCAD has enlisted Northrop Grumman Aerospace Systems (NGAS) in a technology development effort associated with the TR202, a LOX/LH2 expander cycle engine driven by independent turbopump assemblies and featuring a variable area pintle injector similar to the injector used on the TR200 Apollo Lunar Module Descent Engine (LMDE). Since the Apollo missions, NGAS has continued to mature deep throttling pintle injector technology. The TR202 program has completed two phases of pintle injector testing. The first phase of testing used ablative thrust chambers and demonstrated igniter operation as well as stable performance at several power levels across the designed 10:1 throttle range. The second phase of testing was performed on a calorimeter chamber and demonstrated injector performance at various power levels (75%, 50%, 25%, 10%, and 7.5%) across the throttle range as well as chamber heat flux to show that the engine can close an expander cycle design across the throttle range. This paper provides an overview of the TR202 program. It describes the different phases of the program with the key milestones of each phase. It then shows when those milestones were met. Next, it describes how the test data was used to update the conceptual design and how the test data has created a database for deep throttling cryogenic pintle technology that is readily scaleable and can be used to again update the design once the Altair program's requirements are firm. The final section of the paper describes the path forward, which includes demonstrating continuously throttling with an actuator and pursuing a path towards integrated engine sea-level test-bed testing

Evaluating the use of graphene electrodes in sub-micrometric, high-frequency n-type organic transistors

In this work we report on fully operational sub-micrometric low voltage OFETs by using graphene as the source-drain electrodes pair and a high-κ ultra-thin dielectric in a local gate architecture. The impact of the graphene electrodes on the miniaturization of the organic devices has been assessed, with particular attention to the influence of the contact resistances as well as the parasitic overlap gate capacitance on the device bandwidth. By the use of a modified Transmission-Line-Method, contact resistances have been analyzed as function of the applied voltages, revealing characteristic functional trends that follow the doping state of graphene electrodes. Through impedance spectroscopy of the electrodes, cut-off frequencies as high as 105 Hz have been estimated, highlighting the peculiar role of quantum capacitance of graphene in such architectures

Eating Problems in Youths with Type 1 Diabetes During and After Lockdown in Italy: An 8-Month Follow-Up Study

Eighty-five youths with T1D and 176 controls aged 8–19 years were asked to complete online questionnaires (ChEAT and EAT-26) measuring disordered eating behaviors (DEBs) during (baseline) and after (8-month follow-up) the lockdown. DEB symptoms in all participants (especially younger than 13 years), glycemic control, and zBMI were found unchanged from baseline to follow-up (all p >.05). After 8 months, the ChEAT/EAT-26 critical score frequency decreased significantly in controls (p =.004), as was the score for the ChEAT/EAT-26’s Oral Control subscale in both groups (T1D: p =.005; controls: p =.01). Participants with T1D, especially those older than 13 years, had higher ChEAT/EAT-26 Dieting scores (p =.037) and lower ChEAT/EAT-26 Oral Control scores (p =.046) than controls. Unchanged DEB symptoms suggest that the COVID-19 restrictions did not significantly affect participants’ eating behaviors and that a general adaptation to the challenges of lockdown and other pandemic containment measures occurred in both T1D and control participants

Disordered eating behaviors in youths with type 1 diabetes during COVID-19 lockdown: an exploratory study

Background: Recent research indicates that patients with type 1 diabetes (T1D) are at higher risk for disordered eating behaviors (DEBs) than their peers without diabetes. The present study aimed to explore the prevalence of DEBs in a sample of Italian children and adolescents with T1D and in matched-pair healthy controls during the COVID-19 lockdown. Methods: In a cross-sectional study, 138 children and adolescents with T1D (aged 8.01–19.11 years, 65 boys) attending a Southern Italian diabetic service and 276 age- and gender-matched healthy peers voluntarily completed an online survey about eating behaviors (ChEAT and EAT-26), anthropometric characteristics, and clinical characteristics. Results: 8.69% (N = 12) of participants with T1D and 13.4% (N = 37) of controls had ChEAT/EAT-26 scores indicating presence of DEBs, with no differences between patients—whether children (total ChEAT score F(1, 157) =.104, p =.748) or adolescents (total EAT-26 score F(1, 255) =.135, p =.731)—and healthy peers. zBMI values were lower than those measured in the latest diabetes visit (p <.0001), while HbA1c values remained unchanged (p =.110). In both groups, adolescents had lower Oral Control scores than children (T1D: F(1, 138) = 20.411, p <.0001, η2 =.132, controls: F(1, 276) = 18.271, p <.0001, η2 =.063); additionally, gender (female) and age were found to be significant predictors of several ChEAT/EAT-26 scores. Conclusions: This exploratory study suggested that children and adolescents with T1D did not experience more DEB symptoms during the COVID-19 lockdown compared to healthy controls. Results revealed DEBs as more of a female adolescent developmental issue rather than a result of the challenges of living with a chronic illness under quarantine measures. Possible effects of parental pressure on their children’s eating behaviors in the context of home confinement and of using a non-diabetes-specific measure to assess DEBs are discussed