Structural evolution of thermal sprayed bismuth sodium titanate piezoelectric ceramic coatings

The structural evolution of lead-free piezoelectric bismuth sodium titanate (BNT) coatings with excess Bi derived from thermal spray process was investigated with transmission electron microscopy (TEM). Bi-rich composition was identified as the nucleation agent of the BNT perovskite phase, and fine-grained microstructure was obtained with more excess Bi. The Bi-rich composition of the perovskite phase crystallized from melt was Bi_xNa_yTiO₃ (0.5 ≤ X ≤ 0.55, 0.46 ≤ y ≤ 0.5). The crystallization of the Bi-rich BNT perovskite phase first from liquid precursor phase would result in continuous depletion of Bi composition in the residual amorphous phase, and thus Ti-rich amorphous phase in the as-deposited coating and sodium titanate secondary phase in the heat-treated coating formed in the composition without enough access Bi. The results and analyses suggest only appropriate compensation with adequate amount of excess Bi can realize single perovskite phase in thermal sprayed BNT-based coatings and hence the superior piezoelectric performance property.     

Analysis of Surface Tension from Aerodynamic Levitation of Liquids

Aerodynamic levitation allows contactless diagnostics of very high-temperature liquid properties. Liquids can be metals or inorganic compounds, and the levitation gas may have any composition. Temperature limitation is dependent on the heating power and radiative properties of the samples, with 3000°C possible for oxides. Surface-tension measurement is based on previous theories, which relate it to specific vibrations of the drop. Rotation and precession of liquid drops are specific aspects of aerodynamic levitation, and their effects are quantified here. Experimental examples for nickel and alumina are also shown and compared with results from previous experiments, when available.     

Nitrogen uptake efficiency in maize production using irrigation water high in nitrate

In order to achieve efficient use of nitrogen (N) and minimize pollution potentials, producers of irrigated maize (Zea mays L.) must make the best use of N from all sources. This study was conducted to evaluate crop utilization of nitrate in irrigation water and the effect N fertilizer has on N use efficiencies of this nitrate under irrigated maize production. The study site is representative of a large portion of the Central Platte Valley of Nebraska where ground water nitrate-N (NO₃-N) concentrations over 10 mg L^–1 are common. Microplots were established to accommodate four fertilizer N rates (0, 50, 100, and 150 kg ha^–1) receiving irrigation water containing three levels of NO₃-N (0, 10, 20 mg L^–1). Stable isotope¹⁵N was applied as a tracer in the irrigation water for treatments containing 10 and 20 mg L^–1 NO₃-N. Plots that did not receive nitrate in the irrigation water where tagged with¹⁵N fertilizer as a sidedress treatment. Sidedressed N fertilizer significantly reduced irrigation-N uptake efficiencies. When residual N uptake is added to first year plant usage, total irrigation NO₃-N uptake efficiencies are similar to total sidedress N fertilizer uptake efficiencies for our cropping system over the two year period. Efficiency of irrigation-N use depends on crop needs and availability of N from other sources during the irrigation season.     

Studies on a new binary accelerator system containing TMTD and amidinothiourea in sulfur vulcanization of natural rubber

It is well known that the use of binary accelerator systems in rubber vulcanization provide better physical and chemical properties to the vulcanizates. The present work reports the results obtained on the study of amidinothiourea as a secondary accelerator along with tetramethyl thiuram disulfide (TMTD) in the sulfur vulcanization of natural rubber. Vulcanizates containing amidinothiourea have an appreciable increase in mechanical properties and better retention of these properties after aging compared to the reference mixes used. These mixes containing amidinothiourea showed appreciable reduction in optimum cure time as well. This suggests a nucleophilic reaction mechanism in the vulcanization reactions under review. Mixes with varying concentrations of amidinothiourea were tried; and the optimum level of amidinothiourea required has been derived based on the cure characteristics of the mixes and physical properties of the vulcanizates. © 1994 John Wiley & Sons, Inc.     

RETRACTED ARTICLE:3D printing of surface characterisation and finite element analysis improvement of PEEK-HAP-GO in bone implant

The International Journal of Advanced Manufacturing Technology - Research and development of polyetheretherketone (PEEK) composites with high thermal conductivities and ideal thermal stabilities...     

Design and construction of microclimate monitoring system

A portable and user-friendly weather monitoring system based on the PIC16F876 microcontroller is described. This instrument measures three parameters: temperature in the range from -10 to +70 degrees C within +/-1 degrees C using an LM335 temperature sensor, wind speed from 0 to 10 m/s within +/-0.1 m/s using a heated bead thermistor, and solar radiation from 0 to 1000 W/m(2) within +/-10 W/m(2) using a solar cell. These variables are displayed digitally, one at a time, with a 5 s separation. The values are stored on EEPROM at 2 min intervals. The instrument is intended for use in agriculture and for educational purposes.     

Getter sputtering system for high-throughput fabrication of composition spreads

We describe a sputtering system that can deposit composition spreads in an effectively UHV environment but which does not require the high-throughput paradigm to be compromised by a long pump down each time a target is changed. The system deploys four magnetron sputter guns in a cryoshroud (getter sputtering) which allows elements such as Ti and Zr to be deposited with minimal contamination by oxygen or other reactive background gases. The system also relies on custom substrate heaters to give rapid heating and cool down. The effectiveness of the gettering technique is evaluated, and example results obtained for catalytic activity of a pseudoternary composition spread are presented.     

Quantitative photochemical immobilization of biomolecules on planar and corrugated substrates: a versatile strategy for creating functional biointerfaces

Methods for the generation of substratespresenting biomolecules in a spatially controlled manner are enabling tools for applications in biosensor systems, microarray technologies, fundamental biological studies and biointerface science. We have implemented a method to create biomolecular patterns by using light to control the direct covalent immobilization of biomolecules onto benzophenone-modified glass substrates. We have generated substrates presenting up to three different biomolecules patterned in sequence, and demonstrate biomolecular photopatterning on corrugated substrates. The chemistry of the underlying monolayer was optimized to incorporate poly(ethylene glycol) to enable adhesive cell adhesion onto patterned extracellular matrix proteins. Substrates were characterized with contact angle goniometry, AFM, and immunofluorescence microscopy. Importantly, radioimmunoassays were performed to quantify the site density of immobilized biomolecules on photopatterned substrates. Retained function of photopatterned proteins was demonstrated both by native ligand recognition and cell adhesion to photopatterned substrates, revealing that substrates generated with this method are suitable for probing specific cell receptor-ligand interactions. This molecularly general photochemical patterning method is an enabling tool for the creation of substrates presenting both biochemical and topographical variation, which is an important feature of many native biointerfaces.