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We have studied magnetocaloric properties of a Ni-Mn-In metamagnetic shape-memory alloy especially designed in order to display low thermal hysteresis. Magnetization and calorimetric measurements under a magnetic field have been used in order to determine isothermal magnetic field-induced entropy changes. Results obtained indirectly from magnetization data, quasi-directly from isofield calorimetric measurements, and directly from isothermal calorimetric runs are systematic and agree well with each other. We have analyzed the reproducibility of magnetocaloric properties with cycling from direct isothermal calorimetric measurements. Due to low thermal hysteresis, we have found that about 80% of the transition entropy change, ΔSt ≅ 25 J/kg K, can be reversibly induced under successive application and removal of a field of 6 T. [ABSTRACT FROM AUTHOR]

We have studied magnetocaloric and elastocaloric properties of a Ni-Mn-Sn(Cu) metamagnetic shape-memory alloy undergoing a magneto-structural transition (martensitic type) close to room temperature. Changes of entropy have been induced by isothermally applying both mechanical (uniaxial stress) and magnetic fields. These entropy changes have been, respectively, estimated from dilatometric measurements giving the length of the sample as a function of temperature at selected applied forces and magnetic fields and from magnetization measurements as a function of temperature at selected applied magnetic fields. Our results indicate that the elastocaloric effect is conventional and occurs in two steps which reflect the interplay between the martensitic and the incipient magnetic transitions. By contrast, the magnetocaloric effect is inverse and occurs in a single step that encompasses the effect arising from both transitions. [ABSTRACT FROM AUTHOR]

A kinetic study of the CO 2 desorption process by carbonated sodium zirconate (Na 2 ZrO 3 ) synthesized by a liquid suspension route is presented using zirconium acetylacetonate and sodium acetate as precursors. Na 2 ZrO 3 was characterized by XRD, SEM and TGA. Na 2 ZrO 3 exhibited a 90% conversion during absorption with respect to the theoretical value. CO 2 desorption kinetic study used three temperatures; 850, 900 °C and 950 °C and three concentrations: 5, 3 and 1% of CO 2 in Ar at 200 ml/min. XRD data shown only slight segregation of the precursors, which led to a small amount of ZrO 2 formation in the solid product. The global rate of the decarbonation reaction of Na 2 ZrO 3 was of first order in CO 2 concentration and strongly dependent on temperature. The calculated apparent activation energy was E A = 23.35 kcal/mol. Na 2 ZrO 3 performance during four continuous cycles, shown an excellent thermal and chemical stability, with the material conversion remaining practically unchanged. [ABSTRACT FROM AUTHOR]

The failure dynamics in SiO2-based porous materials under compression, namely the synthetic glass Gelsil and three natural sandstones, has been studied for slowly increasing compressive uniaxial stress with rates between 0.2 and 2.8 kPa/s. The measured collapsed dynamics is similar to Vycor, which is another synthetic porous SiO2 glass similar to Gelsil but with a different porous mesostructure. Compression occurs by jerks of strain release and a major collapse at the failure point. The acoustic emission and shrinking of the samples during jerks are measured and analyzed. The energy of acoustic emission events, its duration, and waiting times between events show that the failure process follows avalanche criticality with power law statistics over ca. 4 decades with a power law exponent ℇ ⊧ 1.4 for the energy distribution. This exponent is consistent with the mean-field value for the collapse of granular media. Besides the absence of length, energy, and time scales, we demonstrate the existence of aftershock correlations during the failure process. [ABSTRACT FROM AUTHOR]

We have studied the elastocaloric effect in a Co-doped Ni-Mn-Ga magnetic Heusler shape memory alloy in the vicinity of its martensitic transition. Measurements of the length change as a function of temperature have been carried out across the transition under applied compression stresses and magnetic fields. The isothermal stress-induced entropy changes have been computed from the experimental data. Results evidence a significant elastocaloric effect associated with the large entropy change of the structural phase transition. The alloy also exhibits a magnetocaloric effect at low applied magnetic fields. It is shown that application of a magnetic field below 1 T increases the estimated elastocaloric relative cooling power by about 20%. A comparison of elasto- and magnetocaloric properties indicates that a similar relative cooling power is reached under application of 10 MPa or 0.8 T. [ABSTRACT FROM AUTHOR]

BACKGROUND Respiratory syncytial virus (RSV) infection causes considerable illness in older adults. The efficacy and safety of an investigational bivalent RSV prefusion F protein—based (RSVpreF) vaccine in this population are unknown. METHODS In this ongoing, phase 3 trial, we randomly assigned, in a 1:1 ratio, adults (260 years of age) to receive a single intramuscular injection of RSVpreF vaccine at a dose of 120 pg (RSV subgroups A and B, 60 itg each) or placebo. The two primary end points were vaccine efficacy against seasonal RSV-associated lower respiratory tract illness with at least two or at least three signs or symptoms. The secondary end point was vaccine efficacy against RSV-associated acute respiratory illness. RESULTS At the interim analysis (data-cutoff date, July 14, 2022), 34,284 participants had received RSVpreF vaccine (17,215 participants) or placebo (17,069 participants). RSV-associated lower respiratory tract illness with at least two signs or symptoms occurred in 11 participants in the vaccine group (1.19 cases per 1000 person-years of observation) and 33 participants in the placebo group (3.58 cases per 1000 person-years of observation) (vaccine efficacy, 66.7%; 96.66% confidence interval [CI], 28.8 to 85.8); 2 cases (0.22 cases per 1000 person-years of observation) and 14 cases (1.52 cases per 1000 person-years of observation), respectively, occurred with at least three signs or symptoms (vaccine efficacy, 85.7%; 96.66% CI, 32.0 to 98.7). RSV-associated acute respiratory illness occurred in 22 participants in the vaccine group (2.38 cases per 1000 person-years of observation) and 58 partici-pants in the placebo group (6.30 cases per 1000 person-years of observation) (vac-cine efficacy, 62.1%; 95% CI, 37.1 to 77.9). The incidence of local reactions was higher with vaccine (12%) than with placebo (7%); the incidences of systemic events were similar (27% and 26%, respectively). Similar rates of adverse events through 1 month after injection were reported (vaccine, 9.0%; placebo, 8.5%), with 1.4% and 1.0%, respectively, considered by the investigators to be injection-related. Severe or life-threatening adverse events were reported in 0.5% of vaccine recipients and 0.4% of placebo recipients. Serious adverse events were reported in 2.3% of participants in each group through the data-cutoff date. CONCLUSIONS RSVpreF vaccine prevented RSV-associated lower respiratory tract illness and RSV-associated acute respiratory illness in adults (260 years of age), without evident safety concerns. (Funded by Pfizer; RENOIRClinicalTrials.gov number, NCT05035212; EudraCT number, 2021-003693-31.) [ABSTRACT FROM AUTHOR]

Mn-rich Ni–Mn–Sn metamagnetic shape memory alloys exhibiting magnetostructural transformation are of a great potential as the base materials for solid-state refrigeration. With the aim of fine tuning of the transformation characteristics and improving functional properties, in the present work we have fabricated polycrystalline Ni 50-x Fe x Mn 40 Sn 10 (x = 0, 2, 4, 6, 8 at.%) melt-spun ribbons, starting from the base alloy with x = 0, which is weakly magnetic in both austenitic and martensitic phases. By exploring martensitic transformation (MT) and magnetic behaviors as a function of Fe doping and magnetic field, we have found that Fe and/or magnetic field reduce the MT temperature and Curie temperature of austenite phase, becoming closer to each other as the Fe-content increases, accompanied by an increase of the magnetic moment of austenite, magnetization jump at MT, transformation volume, and magnetic contribution, ΔS M , to the total entropy change at MT. The ribbons present moderate values of ΔS M equal to 11 J kg −1 K −1 at 5 T for x = 8, moderate thermal hysteresis (10–14 K) nearly independent of Fe doping or magnetic field, and adjustable structural and magnetic transition temperatures close to room temperature. [ABSTRACT FROM AUTHOR]

Abstract: Microstructure, martensitic transformation temperatures, hardness, and magnetic properties have been studied in Co–Ni–Ga alloys for different compositions of Co and Ni. Hardness, transformation temperatures and thermal hysteresis show a decrease with Co content. On the contrary, maximal magnetization, and magnetic hysteresis both grow with cobalt composition. [Copyright &y& Elsevier]

Abstract: Some thermal and structural characteristics of Ni–Fe–Ga alloys were studied by means of differential scanning calorimetry (DSC), thermo mechanical analysis (TMA), and X-ray diffraction techniques. It was observed that martensitic transition temperature rapidly decreases and Curie temperature increases with Fe content. The order–disorder transition temperature from a L21 to A2 structures grows linearly with iron content, as measured by TMA. TMA has been found as a useful tool to perform these characterizations. [Copyright &y& Elsevier]