Understanding the thermodynamic micro-environment inside a pan coater using a data logging device

Objective: The objective of the current study was to establish the use of PyroButton data-logging device to monitor and quantify the thermodynamic environment (temperature and humidity) of a pan coating process.

Material and methods: PyroButtons were placed (fixed) at various locations in a pan coater, including exhaust plenum, spray-gun bar, baffles and were also allowed to freely move with the tablet-bed. A full factorial design of experiments (DOE) study on three process parameters, exhaust temperature, pan speed and spray rate was conducted on a 24 inch pan coater, using a coating system and a core tablet combination expected to have a narrow process operating space.

Results: It was shown that the PyroButtons can provide a detailed and useful signature of the coating process. PyroButton data showed that the tablet-bed temperature was always lower than exhaust temperature and that the difference was a function of the operating conditions such as spray rate. Similarly, the tablet-bed humidity was found to always be higher than exhaust humidity. Some of the DOE batches showed coating defects (logo-bridging). It was shown that the relative humidity (RH), as measured by the freely-moving PyroButtons in the tablet-bed, correlated well with the logo-bridging events. A critical RH value (30%) was established, above which logo-bridging was observed for the selected formulation.

Conclusions: This study showed that PyroButtons can provide very meaningful micro-environmental data that can be correlated to coating defects, and can aid in establishing a process design space for a given coating and tablet formulation.     

Description of integrated competency examination: tools to assess the chiropractic curriculum effectiveness and students' competency levels

Los Angeles College of Chiropractic (LACC) has developed a variety of methods to monitor the effectiveness of its competency based/problem-centered curriculum. The College introduced two Integrative Competency Examination courses (ICE I and ICE II) to assess the chiropractic program's effectiveness and students' competency levels. The ICE courses are pass/fail examinations that use a multistation, objective structured clinical examination (OSCE) format that involves standardized patients along with cognitive assessment of basic science information as methods of evaluation. ICE I requires students to perform psychomotor skills and interpret clinical data; ICE II requires students to perform at a higher level. They are directed to select, perform and interpret clinical data appropriately and correlate this data with relevant basic science information. Through these two levels of evaluation, the educational program, the individual courses and the competency level of each student are assessed. This paper describes the format, content and evaluation tools used in the ICE courses as well as the potential benefits of the courses.     

Materials Characterization of Cobalt Antimonide Nanostructures as Thermoelectric Material

Abstract

Cobalt antimonide (CoSb₃) nanoparticles, a binary skutterudite structure, are synthesized by following solvothermal method using water as solvent. The solvothermally processed powders are annealed to remove the excess Sb to achieve single phase CoSb₃ nanoparticles, and are examined by X-ray diffraction (XRD) indicating the formation of cubic phase of CoSb₃. The structural analysis by selected area electron diffraction (SAED) and the elemental composition of 1:3 for Co and Sb using energy dispersive X-ray spectrophotometer (EDX) predicts formation of high purity crystalline CoSb₃ nanoparticles. Morphology of the annealed CoSb₃ powders observed using field emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM) indicates particle size of 50-100?nm. The ultraviolet–visible (UV-Vis) absorption spectroscopy estimates an energy gap of 3?eV. The nanosized CoSb₃ skutterudites are potential intermediate-temperature thermoelectric materials with further application in developing efficient thermoelectric modules.     

Plane Strain Deformation in Generalized Thermoelastic Diffusion

The present investigation is concerned with plane strain deformation in homogeneous isotropic generalized thermoelastic diffusion subjected to a normal force, thermal source, and chemical potential source. Laplace and Fourier transform techniques are employed to solve the problem. The integral transform have been inverted by using a numerical technique to obtain the displacements, stresses, temperature distribution, and chemical potential distribution. The numerical results of these quantities are illustrated graphically to depict the response of various sources in the theories of thermoelastic diffusion and thermoelasticity for a particular model. Some particular cases have been deduced from the present investigation.     

Stepwise Depletion of Coating Elements as a Result of Hot Corrosion of NiCrAlY Coatings

Present investigation deals with the hot corrosion behaviour of the NiCrAlY coatings deposited by HVOF technique on Superni76 under cyclic conditions at 900  °C in the presence of Na₂SO₄ + 60% V₂O₅ salt. The weight change behaviour of the coatings was followed with time up to 200 cycles and K _p value was calculated for the hot corrosion process. Surface and cross-section of the corroded samples were examined by FESEM/EDS and XRD to follow the progress of corrosion up to 200 cycles. In earlier cycles, the corrosive species oxidised top surface of the coatings. With increasing number of cycles, oxidation of the coatings occurred up to 40-μm depth. A Cr-depleted band was seen below the oxide scale. Further increase in number of cycles led to migration and oxidation of Al to form Al₂O₃ sublayer at coating/scale interface, thereby leading to formation of Al-depleted zone in the coating below the Al₂O₃ sublayer. The corrosion resistance of the NiCrAlY coatings is attributed to the formation of the continuous and dense Al₂O₃ sublayer at the coating/scale interface, which acts as barrier to the migration of Cr to the surface. The appearance of Al₃Y after 100 and 200 cycles also contributes to the increased corrosion resistance of coatings after 100 and 200 cycles.     

First Bovine Serum Albumin‐Promoted Synthesis of Enones,Cinnamic Acids and Coumarins in Ionic Liquid: An Insight into the Role of Protein Impurities in Porcine Pancreas Lipase for Olefinic Bond Formation

During studies on exploiting the catalytic promiscuity of crude porcine pancreas lipase (PPL) in ionic liquid for CC bond formations, bovine serum albumin (BSA) was found to be competing for these reactions. After a detailed investigation, we establish that these transformations are possible by unspecific protein catalysis rather than catalytic promiscuity of “PPL” – a first insight into the role of protein impurities in crude enzyme. Thus, a novel and highly efficient, environmentally friendly approach involving synergistic catalysis by bovine serum albumin‐1‐butyl‐3‐methylimidazolium bromide (BSA‐[bmim]Br) has been developed for the synthesis of (E)‐α,β‐unsaturated compounds including a one‐pot cascade synthesis of cinnamic acids and coumarins via aldol, Knoevenagel and Knoevenagel–Doebner condensations.     

Appreciable Magnetic Moment and Energy Density in Single-Step Normal Route Synthesized MnBi

We study the structural and magnetic properties of the MnBi intermetallic compound. The LTP (Low Temperature Phase) MnBi compound is successfully synthesized in single step by vacuum encapsulation technique and rapid quenching from phase formation temperature. The phase purity and the magnetic moments of MnBi are highly dependent on heat treating schedule. The best phase purity and the magnetic moment are found for a heat-treated sample at 310 °C for 48 h. Rietveld fitted X-ray diffraction (XRD) patterns revealed that the studied MnBi compound is crystallized in hexagonal P63/mmc space group with minute presence of unreacted Bi and Mn phases. The scanning electron microscopy (SEM) study is carried out to visualize the grains morphology and phase identification. The bulk MnBi powder showed appreciable magnetic moment of ～62 emu/g at 6 Tesla and maximum energy product BH _max of 4.01 MGOe at 6 Tesla. The magnetic properties of synthesized MnBi show that it could be a potential candidate for rare earth free permanent magnets.     

Modification of oxide inclusions in calcium-treated Al-killed high sulphur steels

A study has been carried out to understand the modification of alumina inclusions in Al-killed high sulphur steel with calcium treatment. For calcium treatment to be effective, a general practice is to desulphurise the steel to prevent the formation of solid CaS inclusions that are harmful to steel quality and final properties. To avoid this additional desulphurising step, the authors developed a new approach of calcium treatment of steel at an industrial scale. This approach involves treating the liquid steel with calcium treatment at low aluminium levels which enables formation of liquid calcium aluminate inclusions (C12A7) in the melt and then adding remaining amount of required aluminium. Based on this principle, Al-S diagram has been developed and calcium treatment has been modified accordingly. The inclusion transformation and morphology were studied using scanning electron microscope /energy dispersive spectroscopy analysis and. activity of CaS was calculated.     

Experimental investigation of recovery and efficiency of calcium addition through cored wire in steel melt at Visakhapatnam Steel Plant

Samples from calcium-treated liquid steel at Visakhapatnam Steel Plant (VSP), Visakhapatnam are studied under scanning electron microscope to understand the inclusion evolution under various operating parameters. The compositions of inclusions are plotted in ternary Ca–Al–S diagram to evaluate the efficiency of inclusion modification and stable casting operation. Process parameters such as amount of calcium addition, bath superheat, and the speed of wire injection are studied for calcium treatment of steel. Both CaFe and CaSi addition are studied, and calcium recovery for CaFe addition is always found to be less than CaSi addition for the same operating conditions. For CaSi addition, the recommended ranges in terms of bath superheat, wire speed, and the amount of calcium addition are identified for the operating conditions studied for VSP, Visakhapatnam.     

添加Al-TiB中间合金对铝合金组织、磨损和压缩变形行为的影响(英文)

在7178铝合金中添加不同比例的Al-10%TiB中间合金,考察TiB对铝合金的晶粒细化、磨损和压缩变形行为的影响。组织观察表明,TiB颗粒起着晶粒细化剂的作用,导致生成球状枝晶。当Al-TiB中间合金的添加量超过20%时,合金的耐磨性和强度随着中间合金添加量的增加而降低,即使其枝晶组织变得更细而接近于球状组织。