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Agriculture is the oldest and most dangerous occupation as compared to other occupations. Agriculture is the major national economic contributor for under-developed nations such as India, Brazil, and South Korea. It was estimated that nearly half of the world labor force involved in agricultural activities. An attempt was undertaken to assess the environmental parameters and occupational health hazards in the view point of environmental conditions in post harvest activities. Three blocks were selected randomly from Jorhat sub-division. Two villages from each block were selected randomly and there by all together six villages and 300 farm women were selected proportionately. Both interview and experimental method was considered for collection of data. Personal and demographic characteristics of the respondents showed that 82 per cent belonged to marginal farmers having 1 acre of land. As regards to age of the respondents, 88 per cent falls in the age group of 30-40 years. The mean temperature was found to be 22°C and mean relative humidity (RH) was observed to be 49 per cent. The lighting condition revealed that the illuminance level were ranges from 21 lux to 95 lux. It was found that mean noise level was 110 db which was more than the permissible limit. Hazards faced by farm women in post harvest activities due to the environmental factors are pain or cramps, indigestion, eye strain, watering of eyes, blurred vision or vision problem, loss of hearing capacity, temporary deafness, headaches and faintness due to working under cold, humid, noisy and inadequate lighting conditions. It was apparent that 63 per cent respondents were belonged to ‘high’ incidence of environmental hazards during the performance of post harvest activities. The angles of average flexion was highest in upper arm (90.62) and extension was in thoracic and it was observed 115.30°indicating deviation of body parts.

Recently, the possibility of exploiting the phenomenon of spin transition (ST) has been intensively investigated, therefore, it is particularly important to study the behavior of ST under various stimuli. Here, the shape and content of the intermediate phase of ST in Hoffmann-like compounds [Fe(Fpz)2M(CN)4](M = Pt, Pd) under external stimuli are studied. For this purpose, magnetic and Raman spectroscopy measurements were carried out. In pressure-induced spin transition (PIST), a mixture of high-spin and low-spin states appears, while in temperature-induced spin transition (TIST), a homogeneous state occurs. The first-order ST induced by pressure has a hysteresis, but is not abrupt. Whereas, the temperature-induced spin transition at ambient pressure is hysteretic and abrupt. To investigate this difference, we discuss using a thermodynamic model that considers elastic interactions, showing that the slope of the hysteresis loop is related to the appearance of internal pressure, which is related to the difference in sample compressibility under high spin and low spin states., Comment: 10 pages, 6 figures

This article discusses the mechanisms of financial support for business, including through the provision of tax benefits and deferrals on loans to business entities, as well as certain non-profit organizations and individuals in the context of the COVID-19 pandemic in Russia and China.

A number of the nanocarbon-metal Nix-C and Co50-C core–shell structures were obtained from phenol-formaldehyde resin as a carbon precursor using a mechanochemical method and pyrolysis at 1034 °K. T...

The features of the critical bending deformation and magnetization of a magnetoactive elastomer (MAE) beam with a fixed end in a transverse uniform magnetic field have been studied. After the beam reaches a critical bending, the symmetry of the beam shape and the symmetry of the MAE magnetic state change spontaneously. At the critical point, a continuous transition from the highly symmetric magnetic state in the unbent MAE beam to the low symmetric magnetic state in the bent MAE beam (this is the angular state with the effective magnetization inclined to the field) takes place. The beam bending occurs due to the gain in the magnetic energy of the beam. The formation of an angular magnetic state in it has a magnetoelastic origin and is characterized by the critical behavior of the mutually related bending and longitudinal effective magnetization of the MAE, but it is the magnetization that plays the role of order parameter. Furthermore, there is no longitudinal magnetization in the absence of bending and, vice versa, there is no bending in the absence of longitudinal magnetization. The influence of a low remanent magnetization, which eliminates the uncertainty in the bending direction, on the critical bending has been analyzed. The role of the magnetorheological effect, which affects the critical field magnitude and leads to the appearance of field-induced bending hysteresis near the critical point, has also been elucidated.

We report phototransferred thermoluminescence (PTTL) induced in microcline by 470 nm blue- and 870 nm infrared-light. A conventional thermoluminescence (TL) glow curve measured from a sample irradiated to 40 Gy produces five composite TL glow peaks P1, P2, P3, P4 and P5 at 90, 123, 166, 298 and 391 °C respectively. The sample produces PTTL peaks also identified as P1, P2, P3 and P4 following illumination by blue or infrared light after irradiation to 40 Gy and preheating to 400 °C. Step-annealing suggests the presence of deep electron traps associated with a signal beyond 500 °C. However, preheating to 500 °C and exposure to blue or infrared light does not produce significant PTTL peaks. For doses between 40 Gy and 100 Gy, the maximum PTTL is emitted within 60 and 150 s of blue light illumination. On the other hand, the same feature under the infrared light illumination occurs within 100-200 s of illumination. PTTL peaks P1, P2, P3 and P4 reproduced under blue light illumination have a linear dose response between 10 Gy and 100 Gy and those reproduced under infrared light illumination have a superlinear dose response between 10 and 100 Gy. In contrast, donor peak P5 in both cases follows sublinear dose response within the same dose range. Fading of PTTL peaks P1, P2, P3 and P4 as well as the donor peak P5 are negligibly small under blue light illumination compared to that of infrared light illumination. PTTL glow curves are also found to be properly reproducible.

Effect of zinc substitution on magnetic properties and AC heating characteristics of Ni1−xZnxFe2O4 (x = 0–1) nanoparticles has been studied. Magnetic parameters, such as saturation magnetization, Curie temperature, specific loss power, have been determined for the samples. It is shown that the samples with a higher zinc concentration (x > 0.5) display reduced values of spontaneous magnetization and Curie temperature as compared to those with x

The magnetization of a magnetoactive elastomer (MAE) with microparticles of soft magnetic carbonyl iron embedded in a highly elastic matrix has been studied. It is shown that at high temperatures its magnetization curve has the form of a specific hysteresis loop. This hysteresis is attributed to the influence of displacement of magnetized particles in the elastically soft elastomer matrix under the effect of magnetic forces, leading to the change of magnetic interaction between the particles. In this case, there is a maximum in the field dependence of the magnetic susceptibility, the occurrence of which has been associated with the competition between re-arrangement of particles, when they are displaced in a magnetic field, and saturation of particles’ magnetization. When the MAE is cooled below approximately 225 K, both the magnetic hysteresis and the maximum in the field dependence of the magnetic susceptibility disappear. When the MAE material is cooled below the solidification temperature of the elastomer matrix, the displacements of the magnetic particles during magnetization are blocked by the rigid matrix. The magnetization reversal of the MAE is reversible. This means that the shape of subsequent magnetization loops remains constant and the sample returns into the initial non-magnetized state after the magnetic field is turned off.

The rotation of a spherical magnetically soft ferromagnetic particle with uniaxial magnetic anisotropy and located in an elastomer through a certain angle under the action of a magnetic field has been studied theoretically. It was found that if the particle loses its mechanical stability, its rotation angle becomes critically dependent on the magnetic field magnitude. The magnetically induced critical rotation of the particle in the elastomer has a magneto-elastic origin and is accompanied by a critical change in the magnetization of the particle multidomain state, as occurs in the case of second-order magnetic phase transitions. The transition of a particle in a soft-elastic elastomer from the multidomain state into a uniformly magnetized one was shown to be independent of the magnitude of the particle magnetic anisotropy field. The particle rotation was found to result in the appearance of a maximum in the field dependence of the magnetic susceptibility.

Polydimethylsiloxane based magnetoactive elastomers demonstrate above the melting transition range (e.g. at room temperature) an induced uniaxial magnetic anisotropy, which grows with increasing magnetic field. By freezing a material down to 150 K, displaced iron microparticles are immobilized, so that the magnetic anisotropy can be measured. Magnetic anisotropy “constant” is a consequence of particle displacements and a characteristic of the energy of internal deformations in the polymer matrix. The maximum anisotropy constant of the filling is at least one order of magnitude larger than the shear modulus of the pure elastomer (matrix). In a magnetic field, the gain in the rigidity of the composite material is attributed to the magnetomechanical coupling, which is in turn a source of anisotropy. The concept of effective magnetic field felt by the magnetization allows one to explain the magnetization curve at room temperature from low-temperature measurements. The results can be useful for developing vibration absorbers and isolators.

Phototransferred thermoluminescence (PTTL) of Al2O3:C,Mg induced by 470 nm blue, 525 nm green, and 870 nm infrared light is reported. Although its conventional TL glow curve measured during heating to 600 °C has seven peaks (labeled I–VII), only peak II is reproduced under phototransfer, except when the sample is preheated to 180 °C when peak IV also re-appears. The dependence of PTTL intensity on the duration of illumination for both PTTL peaks is analyzed using phenomenological and kinetic models as systems of acceptor and donors, with the number of the latter determined by experiment. The intensity of PTTL increases with the temperature of illumination with an activation energy of thermal assistance of either 0.015 ± 0.002 or 0.047 ± 0.002 eV when either 470 or 525 nm light is used but decreases at elevated temperatures with an activation energy of thermal quenching equal to 0.51 ± 0.02 eV independent of illumination wavelength. The long term behavior of time-response profiles for a system of one acceptor and a single donor, as an exemplar, as studied by stability theory, shows an unstable critical point. Mechanisms for the PTTL are discussed and the emission is ascribed to electron centers in the oxygen sub-lattice.

Selection of seed is a woman exclusive post-harvest activity which is performed manually. Work-related musculoskeletal disorders (WMSDs) are common health problems among the farm women. The use of personal protective equipments (PPE) is not common among the farm women for the reduction of occupational health hazards. A paddy stripper was designed for reducing occupational health hazards of farm women in paddy seed selection activity. The paddy stripper is made of indigenously grown Bamboo plant and hence easily affordable. Fifty farm women who are actively involved in paddy selection activity were randomly selected from two selected villages of Jorhat, Assam. Pinch hand position is one of the identified risk factors in seed selection activity. Pinch grip was measured with pinch dynamometer during the operation. There was a decrease of pinch grip strength (30%) during the seed selection activity. The incidences of musculoskeletal problems were observed to be ‘severe’ to ‘moderate’ in seed selection activity in conventional method. A scale developed by Corlett and Bishop (Corlett and Bishop in Ergonomics 19:175–182, 1976 [2]) was used in identifying the zones of discomfort in different body parts with use of paddy stripper. Highest percentage (87%) of farm women experienced ‘no discomfort’ in wrist, upper back, and shoulder in use of improved paddy stripper as compared to conventional method in performance of the activity. The use of paddy stripper reduced occupational health hazards specially cut and wounds and reduced the severity of musculoskeletal problems of farm women in seed selection activity.

A magnetoactive elastomer (MAE) consisting of single-domain La0.6Ag0.2Mn1.2O3 nanoparticles with a Curie temperature close to room temperature (TC = 308 K) in a silicone matrix has been prepared and comprehensively studied. It has been found that MAE particles are magnetized superparamagnetically with a low coercivity below 10 Oe at room temperature and above. The influence of magnetic anisotropy on the appearance of torque is justified. A coupling between magnetization and magnetoelasticity has also been established. The mechanisms of the appearance of magnetoelasticity, including the effect of MAE rearrangement and MAE compression by magnetized particles, have been revealed. It has been found that the magnetoelastic properties of MAE have critical features near TC. The magnetoelastic properties of MAE disappear at T > TC and are restored at T

Background Methicillin-resistant Staphylococcus aureus (MRSA) is capable of causing a wide range of infections. Colonized healthcare workers (HCWs) and contaminated hand-touch surfaces act as a potential source of MRSA in hospitals. This study was conducted to detect the carriage of MRSA in the hands of HCWs during patient care to check awareness among HCWs to follow proper hand hygiene protocol. Materials and methods This study was a cross-sectional point prevalence study done in wards and intensive care units (ICUs) of a tertiary care hospital. Hand cultures were collected from HCWs after the clinical rounds, without prior information about the procedure. It was done on three consecutive days to include maximum HCWs from the hospital. Cultures were taken before and after the use of alcohol-based hand rub. Hand cultures were obtained by asking HCWs to touch the surface of chromogenic screening agar for MRSA with their fingertips and thumbs of both the hands. Results Of a total of 62 HCWs screened, 32 (51.61%) were positive for MRSA. Among these, seven were doctors. After using alcohol-based hand rub, six HCWs were still positive for MRSA. Another important finding on this screening agar was detection of Candida on the hands of HCWs. Conclusion Regular monitoring of hand hygiene compliance is vital to prevent the spread of nosocomial infections. The MRSA screening agar is rapid, simple, cost-effective, and useful to identify the carriage of not only MRSA but also Candida (in the wake of nosocomial outbreaks with Candida auris) in the hands of HCWs. Further studies are required to evaluate the transmission rate of MRSA from HCWs to patients in Indian hospitals. How to cite this article Sharma A, Kalita JM, Nag VL. Screening for Methicillin-resistant Staphylococcus aureus Carriage on the Hands of Healthcare Workers: An Assessment for Hand Hygiene Practices. Indian J Crit Care Med 2019;23(12):590–592.

We describe a first-order phase transition in an isotropic non-Heisenberg ferromagnet induced by a magnetic field with a fourth-order spin exchange interaction at temperatures above the Curie point. The field behavior of the magnetization is analyzed and the temperature dependences of the critical fields of the stability of the paramagnetic and ferromagnetic phases as well as the critical field of the phase transition between them are determined. It is shown that this first-order phase transition has a finite amplitude of the magnetization jump and can occur in small magnetic fields. An H–T phase diagram is presented. It is found that the amplitude of the phase jump during the magnetic field-induced transition from the paramagnetic to the ferromagnetic phase can exceed the magnitude of the entropy change of an isotropic Heisenberg ferromagnet by two orders of magnitude when it is magnetized at the Curie point. It is shown that the expansion of the free energy model up to the 6th power in magnetization can only qualitatively describe the entropy behavior in the phase transition between the paramagnetic and ferromagnetic phases.

Phototransferred thermoluminescence (PTTL) from BeO is reported. The conventional TL glow curve has five peaks, I–V, at 50, 182, 283, 437, and 535 °C when measured at 1 °C s−1 The dominant one is peak II. Only the first three reappear under phototransfer. Electron traps for peaks IV and V weakly contribute to the PTTL. The PTTL at peak III, supposedly associated with these weak donors, is counterintuitively intense. All PTTL peaks are affected by light-induced fading, thermal quenching, and all but peak II by thermal fading. The activation energy for thermal quenching was found as 0.56±0.02, 0.53±0.05, and 0.94±0.07eV using peaks I, II, and III, respectively. Electronic processes relevant in the PTTL of BeO are discussed. PTTL time-response profiles are analyzed using systems of coupled linear differential equations as well as by theoretical modeling.

Numerical calculations of magnetization reversal loops of nanogranular films having perpendicular anisotropy in an inclined magnetic field at finite temperature, for film “quality parameters” both less than, and greater than, one. The calculations are performed with consideration of the film's demagnetizing field in the two-level approximation for the energy of the granule. It is found that the hysteresis of the transition fields between states with uniformly directed and non-uniformly directed magnetic moments for all granules narrows with increasing temperature and field deviation angle from the normal to the film. As the field deviation increases this hysteresis vanishes, and there is a transition from the uniformly magnetized state of the granules to the equilibrium non-homogeneous state without hysteresis. In the case of large field deflection angles, at finite temperature the magnetization consists of three regions. At the center of the magnetization curve there is a hysteresis region in which the m...

We present a theoretical description of a quantum phase transition in a dimerized antiferromagnet, induced by an external magnetic field. The description of such transitions is constructed by determining the minimum of the Lagrange function which depends on the parameters of the ground-state crystal wavefunction. We determine that during a crystal transition from the singlet state of the dimer to the state with a noncollinear spin orientation, an order-order type phase transition occurs. We show that in the case of a single-axis character of the exchange anisotropy, the location of the quantum phase transition critical point is affected by the spin-spin interactions inside the dimer. Additionally, analogous to the classical Neele antiferromagnets, single-axis type anisotropic spin-spin interactions between dimers, shift the point of the spin-flip transition from the noncollinear antiferromagnetic phase to the ferromagnetic phase.

Ln-doped La 0.7− x Ln x Sr 0.3 MnO 3 (Ln – Nd and Sm) nanoparticles were synthesized via sol-gel method with further heat treatment at 800 °C. Crystallographic, magnetic and calorimetric properties of the obtained nanoparticles have been studied. According to X-ray data, all particles have crystalline perovskite structure and lattice cell volume decreases with growing Ln content. It follows from magnetostatic measurements that the increase in Ln content results in lowering Curie temperature and reduction of room-temperature magnetization. Calorimetric studies show that the action of an external alternating magnetic field causes the effective heating of nanoparticles at temperatures lower than Curie temperature, while heating efficiency strongly weakens upon a transition into paramagnetic state. Thus, fine tuning of the Curie temperature of nanoparticles allows controlling the maximal temperature achieved during the heating, which is important for application of these materials as mediators of self-controlled magnetic nanohyperthermia.

A Monte-Carlo (MC) method is used to study the magnetization of an ensemble of Stoner-Wohlfarth particles with interparticle interactions of a ferromagnetic type. A modification of the procedure for the MC calculation is proposed to speed up the calculations. The magnetization of the ensemble is studied at different temperatures and for different ratios of the exchange field of the interparticle interaction and the uniaxial magnetic anisotropy field of the particles. It is shown that Neel relaxation has a significant influence on the coercive properties of the ensemble if the interparticle exchange field does not exceed the anisotropy field of the particles. It is also found that, at low temperatures, the coercive properties of Stoner-Wohlfarth particles with exchange interactions are related to the loss of stability of the orientation of the average magnetic moment vector of the particles. At high temperatures, the coercivity of the particle ensemble is associated with the complete loss of stability of t...

Magnetic nanoparticles constitute promising tools for addressing medical and health-related issues based on the possibility to obtain various kinds of responses triggered by safe remote stimuli. However, such richness can be detrimental if different performances are not adequately differentiated and controlled. The aim of this work is to understand and systemize different kinds of magnetic-field-induced response for an ensemble of lanthanum-strontium manganite nanoparticles, which are considered as promising materials for self-controlled magnetic hyperthermia. A complex set of static and dynamic magnetic measurements accompanied by a numerical simulation of DC and AC magnetic behavior has been carried out. It is shown that to achieve adequate results, the dispersion of particle sizes and/or magnetic parameters should necessarily be taken into account. A quantitative description of the magnetic behavior of the ensemble should comprise two groups of nanoparticles differentiated according to the regime of their magnetization reversal: one group, which demonstrates non-hysteretic behavior similar to a superparamagnet and another one, which shows magnetic hysteresis characteristic of blocked particles. The fraction of nanoparticles in each group depends not only on the nanoparticles' parameters (in particular, their size), but also on the parameters of the external AC magnetic field (amplitude and frequency) used for remagnetization. The main outcome of this work is the development of a procedure which allows one to separately analyze contributions from different groups of nanoparticles and find the regularities of the redistribution of nanoparticles between these groups on changing the parameters of the external AC magnetic field. The results show the directions to enhance the heating efficiency of ensembles of magnetic nanoparticles and pave the way for further optimization of their characteristics and the parameters of the external field.

Thermoluminescence (TL) and infrared light stimulated luminescence (IRSL) of limestone (CaCO

The results of a study of magnetoactive elastomers (MAEs) consisting of an elastomer matrix with embedded ferromagnetic particles are presented. A continuous critical bending induced by the magnetic field, characterized by a critical exponent for the bending magnitude, and the derivative of which has a singularity in the critical region is reported for the first time. The mechanical stability loss and the symmetry reduction of the magnetic state, which are interrelated with each other, take place at the critical point. The magnetization in the high-symmetric state (below the critical point) is directed along the magnetic field and the torque is absent. Above the critical point, the magnetization and the magnetic field are noncollinear and there arises a torque, which is self-consistent with the bending. The magnetic field dependence of the MAE bending was found to have a hysteresis, which is associated with the magneto-rheological effect. The shape memory effect was also obtained for the MAE bending in a cycle consisting of magnetization, cooling (at H ≠ 0), and heating (at H = 0). The influence of the critical glass transition temperature of the matrix, as well as its melting/solidification temperature, on the magnetic shape memory effect was studied.

Field-induced magnetic quantum phase transitions in the Van Vleck paramagnet with easy-plane single-ion anisotropy and competing Ising exchange between ions with the spin S=1 have been studied theoretically. The description was made by minimizing the Lagrange function at zero temperature (Т=0) and the free energy at T ≠ 0 . Stable and unstable solutions of equations corresponding to the case ψ 0 = | 0 〉 asymptotically transform into those following from the Lagrange function at Т=0. First-order phase transitions from the Van Vleck paramagnet state into the ferromagnet one were found to take place at a sufficiently high single-ion anisotropy. The entropy of such a magnet was shown to grow with its magnetization, as it occurs for antiferromagnets. At the point of quantum phase transition, the entropy has a jump, which magnitude depends on the ratio between the Ising exchange and anisotropy constants, as well as on the temperature. The described magnetic phase transition was supposed to be accompanied by the magnetocaloric effect. In the case when the Ising exchange dominates over the single-ion anisotropy, the magnetization reversal of ferromagnetic state by an external field was shown to be a phase transition of the first kind, which does not belong to orientational ones and which should be regarded as a quantum order-order phase transition.

This paper is focused on the analysis of hysteresis and critical phenomena of magnetization reversal of superferromagnetic (SFM) state in nanogranular (NG) Co/Al 2 O 3 film with perpendicular anisotropy. It was demonstrated that the transition from the multidomain SFM state to the homogeneous SFM state, during the magnetization process, occurs critically. The value of the field of critical transition to the homogeneous state depends on the demagnetization field, granular anisotropy and interparticle exchange anisotropy. It turned out that the temperature dependence of the coercive force of the film, despite its SFM state, accords with the Neel–Brown formula for anisotropic single-domain ferromagnetic particles, but has an anomalous angular dependence. It was concluded that domain wall motion affects these features of the coercive field. The domain wall movement may occur due to the overturn of magnetic moments of particles in the boundaries between the superdomains. At the same time, the main factors influencing the coercivity are the anisotropy of the particles, which blocks their magnetic moment reorientation, and demagnetizing factor of the film. Together they lead to the anomalous angular dependence of the coercive field.

Two series of nanosized cobalt spinel ferrites CoFe2O4 are synthesized from metal salts using high-energy ball milling with the addition of NaCl as a growth agent (series CFO-NaCl), and without (CFO Series). The particle properties are characterized using atomic force microscopy, as well as magnetic and calorimetric measurements. It is shown that the average sizes of the nanoparticles were ∼5.6 and ∼10.3 nm for CFO and CFO-NaCl series, respectively. We performed magnetostatic measurements and determined the parameters that are required to analyze the magnetic state and remagnetization processes of the nanoparticles. It is shown that the blocking temperature is ≈160 K for CFO samples and ≈300 K for the CFO-NaCl series. It was concluded that at 293 K the CFO series particles exhibit a superparamagnetic state, whereas the CFO-NaCl series are in the blocked state. The specific loss power that is scattered by the synthesized nanoparticle ensembles placed in an alternating magnetic field, is measured experiment...

The magnetization of a two-sublattice Ising antiferromagnet with easy-plane single-ion anisotropy, which is accompanied by two phase transitions, has been studied. The both phase transitions are induced by the magnetic field. One of them is isostructural, i.e., the system symmetry remains unchanged and a transition between two antiferromagnetic states with different sublattice magnetizations takes place. The other phase transition occurs when the antiferromagnetic state transforms into the ferromagnetic one. At both phase transitions, the field dependence of the system entropy has two successive positive jumps, which is not typical of ordinary antiferromagnets. On the other hand, if the temperature of the system is higher than the tricritical temperature of the isostructural phase transition, there appears a continuous maximum in the field dependence of the entropy.

Phase transitions from the low-spin to the high-spin state are a unique physical phenomenon without lowering of symmetry. In contrast to magnetic phase transitions, for which vector or tensor of physical quantities are used as order parameters, we have shown that for spin phase transitions the order parameter is a scalar quantity—the thermodynamic mean of spin square operator, which was not previously used at all in the theory of phase transitions. The free energy in the form of a functional of this order parameter is determined, and the phase diagrams for spin transitions are constructed. The influence of the pressure on spin transition is analyzed also. It is shown that the spin Hamiltonian with this order parameter allows one to obtain all possible spin transformations in compounds. At the same time, this order parameter correctly reflects the physical nature of the spin transition phenomena.

Magnetic nanoparticles of the La0.6Ag0.2Mn1.2O3 manganite with superstoichiometric manganese have been obtained using nitrate pyrolysis method. Structure, phase composition, morphology, and size of the nanoparticles have been determined. Magnetic properties of the La0.6Ag0.2Mn1.2O3 nanoparticles have been studied near the temperature of their magnetic ordering. It has been shown that magnetization near critical temperature is equilibrium and superparamagnetic. It has been found that magnetization and a change in entropy have critical behavior with a large value of the magnetocaloric effect. Interrelation between the critical indices of magnetization and the magnetocaloric effect has been established. In strong magnetic field, these properties of the nanoparticles have behaviour comparable with bulk samples. In weak magnetic field, the effect of superparamagnetism on the entropy has been found. The magnitude of the contribution from superparamagnetism to the magnetocaloric effect has anomalous temperature dependence. The obtained results of the influence of superparamagnetism on the thermomagnetic properties of the nanoparticles near critical temperature are important to understand and can be used for applied applications.

Combined study of magnetization reversal and AC field-induced processes has been carried out for lanthanum-strontium manganite nanoparticles with an average particle size near 30 nm. Hysteretic behavior with magnetic anisotropy fields of the order of one hundred Oersteds is independently confirmed by magnetic and calorimetric measurements. The regularities of the AC field-induced heating processes occurring in magnetic fluids based on the synthesized nanoparticles are specified and linked to magnetic anisotropy characteristics. The ways to optimize nanoparticle parameters and experimental conditions for the achievement of maximal heating efficiency are outlined.

It was found that the anomalous magnetorheological effect observed in initially unstructured magnetoisotropic magnetoactive elastomers, i.e., the growth of their effective shear modulus in an external magnetic field by almost two orders of magnitude, is a result of the uniaxial magnetic anisotropy induced by the magnetic field. An additional magnetoelastic contribution to the mechanical stress created by the induced magnetic anisotropy counteracts the shear and increases the effective shear modulus of the magnetoactive elastomer when the latter is magnetized. Numerical estimates made for the magnitude of magnetorheological effect are in good agreement with known experimental data.

We propose a theoretical approach for calculating effective electric and magnetic properties of composites, with field dependent restructuring of the filler. The theory combines the effective medium approximation, extended to a field-dependent (variable) percolation threshold, with an approximate treatment of the nonlinearity of material properties. Theoretical results are compared with experiments on magnetorheological elastomers, which in the context of investigated phenomena are often called magnetoactive elastomers (MAEs). In MAEs with soft polymer matrices, the mutual arrangement of inclusions changes in an applied magnetic field. This reorganization of the microstructure leads to unconventionally large changes of electrical and magnetic properties. The obtained theoretical results describe observed phenomena in MAEs well. For the magnetodielectric effect, qualitative agreement between theory and experiment is demonstrated. In the case of magnetic permeability, quantitative agreement is achieved. The theoretical approach presented can be useful for the development of field-controlled smart materials and design of intelligent structures on their basis, because the field dependence of physical properties can be predicted.

We report the effect of pre-dose on the thermoluminescence (TL) and optically stimulated luminescence (OSL) dose response of α-Al

Magnetic properties of a magnetoactive elastomer (MAE) filled with {\mu}m-sized soft-magnetic iron particles have been experimentally studied in the temperature range between 150 K and 310 K. By changing the temperature, the elastic modulus of the elastomer matrix was modified and it was possible to obtain magnetization curves for an invariable arrangement of particles in the sample as well as in the case when the particles were able to change their position within the MAE under the influence of magnetic forces. At low (less than 220 K) temperatures, when the matrix becomes rigid, the magnetization of the MAE does not show a hysteresis behavior and it is characterized by a negative value of the Rayleigh constant. At room temperature, when the polymer matrix is compliant, a magnetic hysteresis exists and exhibits local maxima of the field dependence of the differential magnetic susceptibility. The appearance of these maxima is explained by the elastic resistance of the matrix to the displacement of particles under the action of magnetic forces., Comment: 16 pages, 6 figures