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Magnetoelectric (ME) composites of suitable ferroelectric and magnetic materials can display elevated magnetic and ferroelectric operational temperatures, along with substantial ME coupling, compared to conventional single‐phase multiferroics. Herein, we describe the synthesis of (1‐Φ) PZTFT‐Φ CZFMO, Φ = 0.1, 0.2, 0.3 (PZTFT: [0.6(PbZr0.53Ti0.47O3)–0.4(PbFe0.5Ta0.5)O3] CZFMO: Co0.6Zn0.4Fe1.7Mn0.3O4)] particulate (0–3) composites and report on the magnetic as well as ferroelectric phase transitions and magnetoelectric coupling. The phase formation and the induced strain in these composites are investigated via Raman spectroscopy. A large bifurcation of the zero‐field cooled‐field cooled magnetization curves confirms the highly anisotropic behavior of the composites. These curves also identify spin glass behavior in the CZFMO phase at ≈230 K. The magnetic phase transition of the composite (Φ = 0.2) is reported to be ≈532 (± 10) K. The temperature dependent dielectric data displays the ferroelectric phase transitions from the PZTFT phase and the broad relaxation peak from the CZFMO phase. The quadratic relationship between the magneto‐capacitance and the magnetization confirms the existence of biquadratic magnetoelectric coupling in the systems. The collective results are consistent with the presence of a direct magneto‐electric effect in the composites, i.e., by the application of magnetic field, the magnetic phase is strained, and this induced strain is responsible for changes of ferroelectric order parameter in the piezoelectric phase. This attribute makes the current composite structure a promising candidate for multiferroic data storage and processing technologies. [ABSTRACT FROM AUTHOR]

Here, we have studied the phase transition and magneto-electric properties of a 70 wt. % Pb(Fe0.5Nb0.5)O3–30 wt. % Co0.6Zn0.4Fe1.7Mn0.3O4 (70 wt. % PFN–30 wt. % CZFMO) multiferroic composite that exhibits a maximum magneto-electric (ME) coefficient of 26.78 mV/cm Oe at room temperature. Raman analysis confirms the formation of composite and development of strain with the shifting of Raman modes. The local symmetry breaking of end members of the composite is observed by the splitting of Raman modes. The first-order derivative of magnetization with temperature (dM/dT vs T) shows anomalies across 140 K due to the PFN phase, whereas the anomaly around 250 K is due to the spin glass transition of the CZFMO phase. The magnetization vs magnetic field (M–H) study at different temperatures reveals the existence of superparamagnetic behavior above 300 K. The temperature-dependent dielectric behavior of the composite shows an anomaly around ferroelectric phase transition (Tm) for the PFN phase along with the broad relaxation peak arising due to the CZFMO phase. The linear behavior of magnetocapacitance (MD%) with the square of magnetization (M2) suggests the existence of biquadratic ME coupling. The ME study on the composite suggests the existence of both direct and converse ME effects. [ABSTRACT FROM AUTHOR]

The Li-doping effects of KTa1-xNbxO3 (KTN) crystals on the site occupancy were investigated by reanalysis of Raman scattering results in the literature and density functional theory (DFT) based first-principles calculations. Above the Curie temperature (TC), the transformation of the local A1(z) mode of polar nanoregions (PNRs) of non-doped KTN into the E(x,y) mode of PNRs was reported in 5%Li-doped KTN. The site occupancy for 5%Li-doped-KTN was estimated using DFT results, and it shows that 4.2%Li ions occupy at A-site, while the 0.8%Li ions occupy at B-site. In 5%Li-doped KTN crystals, the hetero-valence random occupation of 0.8%Li ions at B-site can be the microscopic origin of the change of the local mode of PNRs. [ABSTRACT FROM AUTHOR]

Magnetoelectric (ME) materials exhibit interesting physics with cross coupling between ferroelectric and magnetic order parameters and thus strong potential to be utilized in memory, spintronics and other multifunctional electronic/magnetic devices. Doping of suitable transition metals in ferroelectrics can induce magnetism and ME coupling and modify the physical properties. Here, we report the structural, electronic, magnetic and ME coupling of 3.5, 5 and 7.5 mol% cobalt doped BaTiO3 (BTO) ceramics. X-ray diffraction and Raman spectroscopy indicate that the samples are single phase having a tetragonal crystal structure with P4mm symmetry. The tetragonality ratio is found to decrease with increasing cobalt content. We observed a Fano-like asymmetric peak in the [A1(LO1)] Raman mode at ∼173 cm−1 in all the cobalt doped BTO samples. The cobalt dopants are shown to be uniformly distributed throughout the surface of the samples. We observed a lowering of the ferroelectric transition temperature and increasing diffusivity parameter with increasing cobalt concentration. The electrical properties of all the samples have been investigated in detail by impedance spectroscopy and ac conductivity studies before and after the ferroelectric phase transitions. All the samples show hysteretic ferroelectric behavior with a clear saturation state that decreases with increasing cobalt content. The observed ferroelectricity in these samples is intrinsic in nature. The 3.5% cobalt doped BTO sample exhibits paramagnetic behavior whereas the 5 and 7.5% cobalt doped BTO samples show ferromagnetic ordering below 43 K. The 7.5% cobalt doped BTO samples show significant ME coupling. [ABSTRACT FROM AUTHOR]

The relaxor-like dynamics of the cubic-tetragonal ferroelectric phase transition was studied by Brillouin and Raman scattering in K(Ta1-xNbx)O3 (KTN) crystals with x=0.40 (KTN40). The local symmetry breaking by the polar nanoregions (PNRs) was observed in a paraelectric phase by Raman scattering on the A1(z) mode of the PNRs with R3m symmetry. Upon cooling from a high temperature, the remarkable increase in the LA phonon damping starts at 45K above the cubictetragonal phase transition temperature of TC-T=308 K, which is defined as the intermediate temperature, T*∼353K, indicating the start of the rapid growth of the PNRs. The coupling between the LA mode and fluctuation of the PNRs caused a remarkable elastic anomaly in the vicinity of TC-T. The analysis of the temperature dependent central peak shows a critical slowing down towards TC-T, which is the evidence for the order-disorder nature of a ferroelectric phase transition. The evolution of the dynamic PNRs is discussed by the estimation of their length scale, and it is found that it starts to increase near T* and gradually grows towards TC-T. [ABSTRACT FROM AUTHOR]

Potassium triniobate (KNb3O8) ceramic powder has been synthesized by a novel aqueous organic gel route relatively at low calcination temperature above 700 °C. Initially, homogeneous K-Nb precursor gels were prepared using the starting materials K-EDTA and Nb-citrate complex. Afterward, the mixture in stoichiometric ratio of K, Nb, and citric acid produced a pale yellow viscous like gel from which precursor powder was obtained after prolonged heating at 80 °C. The X-ray diffraction patterns reveal the formation of nearly single crystalline phase of KNb3O8 powder calcinated from 750 to 800 °C. Furthermore, the particle size of KNb3O8 powder is also estimated in the nano range using XRD data by the Debye-Scherrer formula. The microstructure, compositional homogeneity, and EDS analysis were performed by scanning electron microscopy that confirmed the fine, almost homogeneous agglomerate microstructure of synthesized ceramics. Thermal analysis showed about 90.3% weight loss of the precursor powder which was mainly responsible for the decomposition of the organic and some other substances. FTIR analysis ensured characteristic absorption bands for the formation of KNb3O8 ceramic powder. [ABSTRACT FROM AUTHOR]

Effect of thickness on structural, optical and morphological properties of 2% copper (Cu) doped zinc selenide (ZnSe) thin films, grown onto chemically and ultrasonically cleaned glass substrate by thermal evaporation method in high vacuum (~10-6 Torr) were studied. Films of 100, 200, 300 and 400 nm thickness were prepared at 200? substrate temperature where annealing temperature and annealing time was fixed at 100? and 1 hour respectively. The X-ray diffraction (XRD) exhibited polycrystalline nature indicating the zinc-blende structure with a preferential orientation along the (111) plane of cubic phase. The grain size was found to be 19.27 nm. Dislocation density and microstrain were also found as 2.691 × 10-3 nm-2 and 1.85 × 10-3 respectively. Atomic Force Microscopy (AFM) study confirmed the growth of grains and their distribution over the entire surface of the films. All the films were characterized optically by UV-VIS-NIR spectrophotometer in the photon wavelength ranging from 300 to 1000 nm. The optical transmittance and reflectance were utilized to compute the absorption coefficient, extinction coefficient and band gap energy of the films. The calculated band gap energy was found to increase (2.99 to 3.94 eV) with varying thickness. The maximum transmittance was found to be 87.65% for the 400 nm film. [ABSTRACT FROM AUTHOR]

The Fano resonance of non-doped KTa1-xNbxO3 (x = 0.32) single crystals was investigated by the Raman spectroscopy. The intensity of central peak (CP) and parameters of the Fano resonance revealed a significant anomaly in the vicinity of the Curie temperature, TC = 259 K. The vibrational dynamics and the symmetry breaking in the cubic phase are discussed in the framework of weak random fields. It is concluded that the coupling between continuum states induced by polar nanoregions (PNRs) and a transverse optic (TO2) phonon at about 194 cm−1 is the origin of a Fano resonance in non-doped KTN crystals. [ABSTRACT FROM AUTHOR]

The effect of integrated use of manure and fertilizers on crop yield, nutrient uptake and soil fertility was studied in the Boro-fallow-T. Aman cropping pattern over two years. The experiment was set up at Bangladesh Agricultural University (BAU) farm, Mymensingh under the AEZ 9 (Old Brahmaputra Floodplain). The field trial consisted of eight treatments and control (no fertilizer or manure), 100% chemical fertilizers (CF), and IPNS based six treatments with six types of manure. Cowdung (CD), CD slurry, Trichocompost (TC) and vermicompost (VC) were added to soil at 5 t ha-1 and poultry manure (PM) and PM slurry applied at 3 t ha-1. For all IPNS treatments, nutrient supply from manure was adjusted with that from chemical fertilizers. In each crop cycle, manure was applied to the first crop (Boro rice) and the residual effect was evaluated on the succeeding crop (T.Aman rice). The IPNS based treatments significantly increased the grain and straw yields of Boro rice and it had also positive residual effect on T.Aman rice. Trichocompost and vermicompost, among the six IPNS treatments, demonstrated higher crop yield and that was followed by poultry manure slurry and cowdung slurry. Integrated use of manure with fertilizers gave on an average 8.3-33.8% and 2.9-18.3% higher grain yield in Boro and T. Aman rice, respectively over sole fertilizers treatment. Higher nutrient uptake by crops (N, P, K & S) was also observed in IPNS treated plots. The IPNS treatments improved soil fertility in terms of increasing organic matter, N, P and S contents of soil after two crop cycles. The study suggests that manure and fertilizers should be used in an integrated manner to achieve sustainable crop yield, without incurring loss to soil fertility. [ABSTRACT FROM AUTHOR]

The electric field effects on precursor dynamics in 5% Li-doped KTa1-xNbxO3(KTN) were investigated under the zero field cooling (ZFC) and the externally applied dc field using micro-Brillouin scattering. The splitting of the transverse acoustic (TA) mode was found below the Curie temperature,TC= 20°C. It can be caused by the co-existence of macro-domains and random nano-domains related to polar-nanoregions (PNRs). AtEC= 0.9 kV/cm, the switching of macro- and nano-domains was observed, at which the TA mode splitting disappeared. Under the electric field of 1.2 kV/cm, the enhancement of creation and growth of PNRs was also studied. [ABSTRACT FROM PUBLISHER]

The effects of electric field and trapped electrons on a ferroelectric phase transition of the 5%Li-doped KTa0.74Nb0.26O3 crystals were investigated by micro-Brillouin scattering and dielectric measurements. In micro-Brillouin scattering, the remarkable changes of the central peak (CP) intensity were observed at the paraelectric cubic to ferroelectric tetragonal phase transition. The critical electric fields to induce the paraelectric to ferroelectric phase transition were found to shift to higher values with increasing temperature. From these CP results, we estimated lines of critical points for phase transitions including critical end point (CEP), (E, T)=(1.6 kV/cm, TC-T+3.4°C) in the composition-temperature-electric field (x-T-E) phase diagram. The clear difference of the CEP was observed between Brillouin result at a fixed small area and dielectric result averaged over all area of a sample. It can be caused by the field gradient, which is induced by the trapped electrons. The existence of gradient of electric field was also discussed using the observed result of position dependence of the CP intensity. [ABSTRACT FROM AUTHOR]

Prediction of ship's response in real voyage condition is essential for efficient ship design. At sea, ships rarely voyage in head wave conditions, and mostly prefer oblique waves for lower resistance and better propulsion. This paper provides oblique wave simulation results for a container, tanker and bulk carrier using a commercial potential flow (PF) based solver, HydroSTAR. Although, PF codes have limitation regarding resistance prediction, they are well reliable in predicting ship motion in waves. The paper aims at providing a relative comparison in trends of ship resistance and motion at different heading angles, for three popular ship models, KCS, KVLCC2 and JBC. The paper should prove useful to both ship builders and sailors for optimal design and weather routing. [ABSTRACT FROM AUTHOR]

Shipbuilding is on the verge of blooming into the major foreign revenue-earning industry in Bangladesh. A number of export-oriented shipyards are developed to build different kinds of ships for local and international clients. For designing a ship, model testing facilities are required not only to predict power requirements but also to evaluate its performance in actual sea operation. At present, Bangladesh does not have this facility. Also carrying out model testing is very expensive and time consuming. Therefore, now-a-days a number of the shipyards in the world are using virtual or computational towing tank facility. Due to improvement of solution algorithm for handling non-linear problem and computational infrastructure, computational or virtual towing tank can be used as a replacement of physical towing tank. In the present study, a numerical or computational towing tank technique named WISDAM which is developed at The University of Tokyo, Japan is described with its applicability in the perspective of Bangladesh shipbuilding industries. [ABSTRACT FROM AUTHOR]

Huttly S R A (Department of Epidemiology and Population Sciences, London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT, UK), Hoque BA, Aziz K M A, Hasan K Z, Patwary M Y, Rahaman M M and Feachem R G. Persistent diarrhoea in a rural area of Bangladesh: a community-based longitudinal study. 1989; : 964–969 As part of a health impact evaluation of a water supply and sanitation project in a rural area of Bangladesh, diarrhoeal morbidity was recorded in children 0–4 years of age using weekly recall in household interviews, during the period March 1984 to December 1987. During the baseline year, 1984, the incidence rate of all diarrhoea episodes (3.8 episodes per child per year), and those defined as pesistent, duration >14 days (0.6 episodes per child per year), showed a similar age distribution, peaking in the 12–23 month age group. Sixteen per cent of all episodes were classified as persistent, and this proportion was greatest in the 0–5 month age group (25%). Children suffering at least one episode of persistent diarrhoea in 1984 also experienced a higher incidence of acute diarrhoea (< = 14 days duration) than those suffering acute diarrhoea only (4.2 versus 3.7 episodes per child per year). Persistent diarrhoea showed a similar seasonal pattern to that of all episodes. Rates of abdominal pain, isolation of and a diagnosis of dysentery were significantly higher in persistent episodes than in acute episodes. Closer follow-up of children during 1986 and 1987, through the recording of all periods of absence of the child from the home, showed that overall diarrhoea incidence rates were little affected when absence was taken into account, but that the incidence of persistent diarrhoea and the proportion of episodes classified as persistent were significantly reduced. The implications of this methodological problem are discussed. [ABSTRACT FROM PUBLISHER]

A randomised three cell study was carried out in 78 children with acute diarrhoea to evaluate the relative efficacy of oral rehydration solution (ORS) made from partially hydrolysed wheat grain, cooked rice powder, or glucose. Twenty six patients with comparable age, body weight, duration of diarrhoea, and degree of dehydration were studied in each of the three groups. Initial rehydration was carried out by using intravenous Dhaka solution within one to two hours followed by administration of oral rehydration solution. The mean ORS intake during the first and second 24 hours of treatment in patients with cholera receiving wheat-ORS and rice-ORS was significantly less compared with those receiving glucose-ORS. The stool output during the same period in patients receiving wheat-ORS and rice-ORS was significantly less compared with those receiving glucose-ORS. Similar trends in both ORS intake and stool output were observed during the next 24 hours. [ABSTRACT FROM AUTHOR]

Faecal alpha 1 antitrypsin was measured in two groups of children with diarrhoea aged 6 months to 6 years during the acute and recovery stages of the illness. Group 1 comprised 19 children with a history of measles in the two weeks preceding admission to hospital. In this group there were six cases of Shigella species, six enterotoxigenic Escherichia coli, and five rotavirus, and two did not yield an aetiologic agent. Group 2 comprised 15 children with diarrhoea only. In this group there were five cases of Shigella species, five enterotoxigenic Escherichia coli, and five rotavirus. Children with rotavirus diarrhoea belonging to both groups showed a transient high faecal clearance of alpha 1 antitrypsin during the acute stage. Post measles cases of diarrhoea showed significantly higher faecal clearance of alpha 1 antitrypsin than group 2 subjects in both the acute and recovery stages. The faecal clearance of alpha 1 antitrypsin in both groups was significantly higher during the acute stage compared with the recovery stage. Highest faecal clearances of alpha 1 antitrypsin were observed in children with post measles shigellosis in the acute stage and they also had persistently raised concentrations, thus suggesting prolonged protein losing enteropathy. [ABSTRACT FROM AUTHOR]