Ordinary Firing Research Articles

Electrical Properties of Textured Bismuth Layer-Structured Ferroelectric Ceramics with Large Number of Layers (m = 5)

Bismuth layer-structured ferroelectrics (BLSF) ceramics are attractive materials for high temperature sensor applications, because of their high Curie temperature Tc (300–900 °C), and the large anisotropy of their electromechanical coupling factor kt/kp or k33/k31. In this study, BLSF ceramics with a large number of layers, namely, (K0.5Bi0.5)2Bi4Ti5O18 + MnCO3 0.3 wt%+ Bi2O3 0.025 wt% (KBT5) and Sr0.75Ca0.25Na0.5Bi4.5Ti5O18 + CeO2 1 wt% [(SC)NBT5] ceramics, were prepared by ordinary firing (OF) and hot forging (HF) methods, and their electrical and piezoelectric properties were examined. Both KBT5 and (SC) NBT5 ceramics showed high Tc values of 545 and 424 °C, respectively. The OF-KBT5 ceramic had an electromechanical coupling factor k33 of 0.14 and a piezoelectric constant d33 of 20 pC/N, whereas the HF-KBT5 ceramic had k33 of 0.17 and d33 of 31 pC/N. On the other hand, the OF-(SC) NBT5 ceramic had k33 of 0.13 and d33 of 17 pC/N, whereas the HF-(SC) NBT5 ceramic had k33 that increased to 0.32 and d33 to 41 pC/N. The k33 and d33 of the HF ceramics were improved compared with those of the OF ceramics. Thus, the KBT5 and (SC) NBT5 ceramics with oriented grains were shown to have good piezoelectric properties with high Tc.

Reconsideration of the firing loop models for dystonia and Parkinson's disease

AbstractParkinson's disease (PD) is a hypokinetic movement disorder with degeneration of dopaminergic and other neurons, whereas dystonia is a hyperkinetic movement disorder caused by various pathogenesis, that is, sporadic, genetic, stroke, brain injury, and other diseases, such as PD. Dopamine receptor 1 (D1R) antagonist and dopamine receptor 2 (D2R) antagonist induce dystonic symptom in monkey. Consistently, D1R antagonist and D2R antagonist decrease locomotion in mice. Moreover, D1R knock‐out (KO) mice and D2R KO mice show motor deficits. In humans, dopa‐responsive dystonia (DRD) is caused by genetically defective dopamine (DA) synthesis. DYT1 dystonia and genetic mouse models show decreased striatal D1R and D2R. Therefore, PD, pharmacological dystonia models, DRD and DYT1 dystonia, have defective DA pathways. Firing of globus pallidus internus (GPi) neurons is increased in PD and dystonia with local anesthesia. However, the ordinary firing loop model cannot explain how defective DA pathways induce dystonia. PD shows thalamic neurodegeneration, whereas PD with dystonia has relatively intact thalamic neurons. Since thalamic GABAergic interneurons are innervated by GPi GABAergic neurons, here I propose to add thalamic GABAergic interneurons between GPi GABAergic neurons and thalamic glutamatergic neurons as thalamic inverse pathway for healthy condition and dystonia, whereas thalamic ordinary pathway due to degeneration of thalamic GABAergic interneurons is suitable to PD. On the contrary, PD with dystonia has both thalamic ordinary and inverse pathways. Although precise thalamic circuits have not been elucidated, discrepancy in the ordinary firing loop model for dystonia seems to be solved by the thalamic switch from dystonia to PD.

High-power piezoelectric properties of quenched (Bi0.5Na0.5)TiO3-based solid-solution ceramics

Lead-free piezoelectric ceramics based on 0.90(Bi0.5Na0.5)TiO3 – 0.04(Bi0.5Li0.5)TiO3 – 0.06BaTiO3 with additives MnCO3 (0.1 wt%) [BNLBT4-6 + Mn0.1], which have a morphotropic phase boundary composition, were prepared by controlling the quenching rate (QR) and, their high-power piezoelectric and electrical properties were examined. The depolarization temperature Td could be increased by controlling the QR. The Td with QR = 15.0 and 0.05 °C/s was 166 and 119 °C, respectively. Thus, Td was increased by about ∼40 °C due to the quenching effect. Moreover, vibration velocities (v0−p) were observed at 1.3 m/s even after quenching. Additionally, the values of d31, ɛ33T/ɛ0, and s11E decreased, whereas Qm increased after quenching. The quenching effect promoted the dielectric and elastic hardening of BNLBT4-6 + Mn0.1 ceramics. After quenching, Td increased, and the value of d31 × Qm maintained the same value as for ordinary firing (OF) with QR = 0.05. Consequently, quenching was found to be effective for increasing the Td and Qm, hence, a promising effect for high-power piezoelectric applications.

Synthesis and enhanced electromechanical properties of Bi(Mg0.5Zr0.5)O3-modified BiFeO3–BaTiO3 piezoceramics by ordinary firing process

Synthesis and enhanced electromechanical properties of Bi(Mg0.5Zr0.5)O3-modified BiFeO3–BaTiO3 piezoceramics by ordinary firing process

LiTaO3 assisted giant strain and thermally stable energy storage response for renewable energy storage applications

Piezoceramics with composition (1–z) [Bi0.5(Na0.84K0.16)0.5TiO3]0.96–0.04SrTiO3–zLiTaO3 (z = 0.00–0.030) were formulated by ordinary firing process following by rapid quenching treatment. Effect of LiTaO3 on the structural, electrical and energy-storage properties were analyzed. For the composition with molar ratio 0.025, room temperature large-field piezoelectric coefficient (Smax/Emax = d33*) of 885 pm/V at 3.6 kV/mm was recorded. Furthermore, for compositions z = 0.025 and 0.030, broad temperature stable dielectric constants and low losses from ~135 to 350 °C with a small variation of ± 15% was observed. Additionally, the energy density for z = 0.025 was ~0.60 J/cm3 in the broader temperature range of 75–125 °C, along with the energy-storage efficiency of greater than 70%. These observations suggest that the studied piezo-material compositions are promising for the ceramic actuators and capacitor applications.

The quenching effects for depolarization temperature of (Bi0.5Na0.5)TiO3 ceramics with Mn dopants

Lead-free ferroelectric and piezoelectric ceramics, (Bi0.5Na0.5)TiO3 (BNT), with Mn dopants were prepared by a quenching procedure after sintering to examine the depolarization temperature Td, and then their electrical properties were investigated. The Td of quenched BNT + xMn (Mn x) decreased with Mn doping. Also, the Td of quenched Mn x was ∼60 °C higher than that of ordinary firing (OF) samples. Furthermore, the difference of Td (ΔTd) between the OF and the quenched process increased with increasing of the Mn-substituted amount. The electromechanical coupling factors k33 of Mn x exhibited the same value after quenching. The coercive electric field Ec was increased from 62 to 95 kV cm−1 with increasing of Mn-substituted amount. Thus, the quenching procedure is an effective way of elevating the Td of Mn-doped BNT-based solid solution systems.

Effects of quenching on bending strength and piezoelectric properties of (Bi0.5Na0.5)TiO3 ceramics

ABSTRACT Lead-free piezoelectric bismuth sodium titanate (Bi0.5Na0.5)TiO3 (BNT) ceramics were prepared by quenching and the correlation among a depolarization temperature T d, the mechanical strength, and their piezoelectric properties were investigated. We controlled the quenching rate in the temperature range from 1100°C to 800°C. We examined the 5 patterns of the quenching rate (QR): 0.05 (ordinary firing, OF), 3.85, 5.77, 6.67, and 15.0 (quenching) oC/s. T d of the rapid quenched sample reached 229°C (QR = 15.0), but its mechanical strength decreased to a quarter of that of the OF ceramics. On the other hand, T d was 211°C at QR = 3.85 which was higher than that of OF-ceramic (QR = 0.05) at about 180°C. Moreover, three-point bending strength (227 MPa) of the quenched BNLT4 (QR = 3.85) was equivalent to that of the OF ceramics (235 MPa). Therefore, both T d and the mechanical strength were improved by controlling the quenching rate.

Quenching effects for piezoelectric properties on lead-free (Bi1/2Na1/2)TiO3 ceramics

Lead-free ferroelectric and piezoelectric ceramics, (Bi0.5Na0.5)TiO3 (BNT), were fabricated by a quenching procedure after sintering, and then their electrical properties were investigated with the aim to increase their depolarization temperature Td. From the measurement of the temperature dependence of dielectric properties, Td increased with increasing quench temperature. The Td of a BNT sample quenched from 1100 °C was 223 °C, which was almost 50 °C higher than that prepared by the ordinary cooling process. From the measurement of P–E hysteresis loops, both the remanent polarization Pr and the coercive field Ec of BNT samples prepared by ordinary firing were almost the same as those quenched from 1100 °C. Additionally, from the measurements by a resonance–antiresonance method, the electromechanical coupling factor k33 of ordinarily fired BNT was 0.45, and that of the quenched BNT was 0.46. From these results, it is clarified that the quenching procedure is an effective way to increase the Td of BNT ceramics without deteriorating ferroelectric and piezoelectric properties.

Loss and Damage Assessment in the Context of Fire Hazards: A Study on Selected Garment Factories in Bangladesh

This research paper has discussed comprehensively about the concept, classification, estimating methods and grading standards of economic losses of fire in garments industries in Bangladesh. The contents of economic losses of industrial fire include the losses of industrial resources" direct economic losses, indirect economic losses and the economic losses on ecological environment. Different estimating methods are adopted for each of them: And, according to the amount of economic losses, industrial fires are divided into extraordinarily serious industrial fire, serious industrial fire and ordinary industrial fire. Most of the fire hazards in RMG sector occurs causing electric short circuit in Bangladesh. And this occurrence creates huge economic damage and loss in this sector. In order to attach of the store house or go down with the factory it becomes impossible to out let of the goods from the store house which happens great loss. Distance of fire station is another reason to control of fire. Locked and narrow emergency exits, panic, dark stairway, full of smoke and the electricity supply been shut down and suffocation for the smoke are the main reasons for death and casualty in the garments factories in our country. Owner of the factory should give remarkably importance in electric supply line, wearing cables and electrical equipments. Government should take steps to operate mobile courts in factory level regularly to ensure occupational safety & health.

Fabrication of dense (Bi1/2K1/2)TiO3 ceramics using hydrothermally derived fine powders

(Bi1/2K1/2)TiO3 (BKT) powders were synthesized by a hydrothermal reaction using anatase TiO2 and Bi(OH)3 under a strong alkaline condition of [KOH] = 12 M. The reaction at 200 °C for 3 h provided a mixture of BKT and Ti-rich fibrous amorphous phases. The single-phase BKT powder with a particle size of 200 nm was successfully obtained by applying a two-step temperature profile for the reaction, which consists of temperature rising up to 160 °C and subsequent holing at 110 °C for 6 h. It was found that washing treatment of the hydrothermal BKT powder with deionized water caused leaching of K+ ions, resulting in the thermal decomposition of the powder during high-temperature heat treatment. It was a key to use ethanol for the washing treatment for preventing the K+ ion leaching. The ceramic sample fabricated by the ordinary firing of the hydrothermal BKT powder at 1060 °C for 2 h had a high density of 94.5 % and showed superior dielectric, ferroelectric, and piezoelectric properties.

On Fire Severity of Building in Performance-Based Design

Analyzing fire severity of designed fire scene is necessary for building fire protection. Ordinary building fire times are calculated from statistic data of their fire heat release rates. Building fire is modeled mathematically to deduce its time-temperature function. Basing on this function curve and Simon Ingberg’s fire severity definition, we establish fire severity classification theory for building fire, including definition and equation of its fire severity, and definition of its fire severity coefficient along with calculation of those coefficients of ordinary combustible solids, and calculation and classification steps for building fire severity.

Semantika vognju gončarnogo gorna v bilorus'kij kul'turi<br>The Semantics of the Pottery Kiln Fire in Belarusian Culture</br>

The article deals with the specific character of the traditional perception of the fire of a pottery kiln in the context of the mythopoetical model of the world among the Belarusians. This flame was identified with lightning, the stormy fire of Perun, which was interpreted as an emanation of this pagan God. The author analyses Belarusian legends on the origin of fire, Slavonic folk beliefs and rites connected with storm, thunder and lightning, the folk attitude to the fire, which was kindled by a thunderclap. There is a close correspondence between these concepts and Vedic mythology. The old Belarusian myth on the origin of the world, where the lightning of Perun plays an important part, has staggering parallels with ancient Vedic cosmogony. The fire in the potter’s kiln is a primordial flame, given by the Thunderer; it is frightful and dangerous owing to its appearance from the other world. It is opposed to ordinary fire, which is secondary and tame. But just this stormy fire, which retains its own demiurgic potential, is used by potters. An archetypal precedent is reproduced in the ceremony of pottery-making, wherein the ceremony is projected in the sacral time of commencement.

Discharge Ability of Hydrant to Ordinary Fire

Discharge Ability of Hydrant to Ordinary Fire

INFLUENCE OF HEATING ON THE VARIOUS STRENGTH PROPERTIES OF ALC PANEL

In official regulations, fire retardant / resistant property is defined as the performance required in the parts of the structure involved in preventing the structure from collapsing, and the fire from spreading until the time the fire ends, in case of an ordinary fire. Nothing is said, however, about such matters as the reuse of building materials after a fire. From the standpoint of the maintenance of ALC-buildings and management, the ability of ALC panel to be reused after being subjected to fire is likely to become an important issue. In the research described here, The bending strength of ALC panel after heating and analysis of ALC crystal structure by X-ray diffraction were studied

Lead-free piezoelectric ceramics based on perovskite structures

The piezoelectric properties of a solid solution based on three components of bismuth sodium titanate (Bi1/2Na1/2)TiO3 (BNT), bismuth potassium titanate, (Bi1/2K1/2)TiO3 (BKT), and barium titanate, BaTiO3 (BT), that is x(Bi1/2Na1/2)TiO3−y(Bi1/2K1/2)TiO3−zBaTiO3, [ $$ x + y + z = 1 $$ , abbreviated as BNBKy:z(x)] and potassium niobate, KNbO3 (KN) based ceramics, that is KN+MnCO3 x wt.%, [abbreviated as KN−Mn x], were studied as a lead-free piezoelectric material. In the case of BNBK2:1 system, high piezoelectric properties were obtained near the MPB composition, and the highest electromechanical coupling factor, k 33 and piezoelectric constant, d 33, were 0.58 for BNBK2:1(0.89) and 181 pC/N for BNBK2:1(0.88). Nevertheless, the depolarization temperature, T d , shifts to lower temperature around the MPB compositions, and the T d ’s of BNBK2:1(0.88–0.90) are only about 100 °C. On the tetragonal side, the T d shifts to higher temperature with increasing the lattice anisotropy, c/a. As T d higher than 200 °C was obtained in the range of x < 0.78, with a k 33 and d 33 for BNBK2:1(0.78) being 0.45 and 128 pC/N, respectively. In the case of Mn doped KN ceramics, dense and non deliquescence KN ceramic were successfully obtained via ordinary firing technique in air by optimizing the fabrication process. Mn doping for KN ceramics was effective to obtain full poling state easily under poling conditions of high temperature and high electric field. As a result, we obtained the excellent piezoelectric properties of k 33 = 0.507 for KN−Mn0.2.

Fabrication and Ferroelectric Properties of Ba-Doped Strontium Bismuth Titanate Ceramics

In the paper, the microstructure and properties of Sr1-xBaxBi4Ti4O15 (SBBT) ceramics with different Ba contents were investigated. SBBT ceramics were fabricated by means of the method combining Sol-Gel process and ordinary firing. The morphology will change when Ba2+ is doped in SrBi4Ti4O15 (SBTi), which will lead to the change of structure and ferroelectric properties. The microstructure of SBTi and BaBi4Ti4O15 (BBTi) ceramics were characterized by scan electron microscopy (SEM). With the increase of Ba2+ doping contents, the sintering temperature of SBBT ceramics decreases, 1120°C for SBTi and 1060°C for BBTi. BBTi ceramics contain more and larger plate-like grains than that in SBTi, the diameter of the grains in BBTi is about 8~10 µm, the thickness is about 2.5 µm. With the increase of Ba2+ doping contents, remanent polarization (Pr) and coercive electric-field (Ec) increase first and then decrease. At the molar ratio of Sr:Ba=0.5:0.5, SBBT ceramics exhibited the highest Pr and Ec.

An Advanced Ferroelectric Properties of the Mn Doped Na0.5Bi4.5Ti4O15 Ceramics Fabricated by Hot-Forging Method

Mn doped Na0.5Bi4.5Ti4O15 (NBTM) ceramics were fabricated by ordinary firing (OF) and hot forging (HF) method. The HF(//) sample is strongly oriented to the c-axis which is confirmed by the X-ray diffraction. Dielectric constant of HF(⊥) sample at Curie temperature is about 5176 which is larger than that (416) of the HF(//) sample. The value of the remnant polarization Pr and coercive field Ecof HF(⊥) samples at 200°C are 17.8 μC/cm2 and 28.5 kV/cm, respectively. From the temperature dependence of conductivity, the activation energy of the HF(⊥) sample is 1.65 eV in the temperature range of 520°C ∼750°C.

Ferroelectric and piezoelectric properties of bismuth layered-structure ferroelectric (Sr,Na,Bi)Bi 2Ta 2O 9 ceramics

Sodium strontium bismuth tantalate (1 − x)[Na 0.5Bi 2.5Ta 2O 9]– x[Sr 0.8Bi 2.15Ta 2O 9] (NSBT- x) solid solution ceramics were synthesized by an ordinary firing method. The ferroelectric and piezoelectric properties of the NSBT- x ceramics were characterized. A single phase with the ABi 2Ta 2O 9-type structure was obtained over the entire composition range. The Curie temperature, T c, linearly decreased with an increase in x from 780 °C ( x = 0) to 410 °C ( x = 1.0). Well-developed P(polarization)– E(electric field) hysteresis loops were observed for all samples. The observed P r-values were independent of the composition x. The coercive field, E c, changed with the composition x and the maximum value of 72 kV/cm was obtained in the NSBT-0.25 ceramics. Superior piezoelectric properties were observed for the NSBT-0.75 ceramics sintered at 1200 °C. The maximum electromechanical coupling factors and mechanical quality factor were k p = 9.0%, k 33 = 15.4% and Q m( k p) = 7000, respectively.

Grain Orientation Effects on the Properties of a Bismuth Layer‐Structured Ferroelectric (BLSF) Bi3NbTiO9 Solid Solution

Bi3NbTiO9 ceramics were prepared by ordinary firing and by hot‐press sintering. The crystal structures of the ceramics were investigated by X‐ray diffractometry. Scanning electron microscopy observation showed that the platelike grains were oriented after hot pressing. Dielectric, piezoelectric, and ferroelectric characterizations, as well as the electrical resistivities, showed remarkable anisotropy in the hot‐pressed samples. Because of grain orientation in the hot‐pressed samples, the remanent polarization and piezoelectric constant in the direction perpendicular to the pressing axis were much higher than in the unoriented, ordinary fired samples.

Tribological Properties of Sr-Ca-Cu-O Films Prepared by Spin Coating Method.

Sr-Ca-Cu-O complex oxide thin films were prepared at different firing temperatures using a spin coating method. Sr0.14Ca0.86CuO2 having layer structure could be prepared at lower temperatures and the method was compared with ordinary firing methods. However, the single phase of Sr0.14Ca0.86CuO2 was not obtained under such spin coating conditions as in this study. The friction properties of four spin coating films sliding against a cemented carbide ball were investigated using a Bowden-Leben type friction tester. Comparatively low friction coefficient and high wear resistance under non-lubrication conditions were obtained with these complex oxide films.