Nanocomposite bulk of mechanically milled Al-Pb samples consolidated pore-free by the high-energy rate forming technique

It is shown that pore-free bulk samples were produced by the high-energy rate forming axis-symmetrical powder compaction method for different application purposes in case of the very different, immiscible Al and Pb metal pair. The starting Al-Pb nanocomposites were made by mechanical milling of atomized Al and Pb powders either in a SPEX 9000 or a Fritsch Pulverisette 4 mill. Due to the conditions that milling was carried out in air, the PbO layer, originally existing at the surface of the atomized Pb powder, ruptured and was also dispersed in the composite. The presence of the nano PbO particles was proven by XRD and TEM (BF, DF, SAED). When the energy of milling was high, the PbO crystallites became so small that they could hardly be seen by XRD technique. Local distribution of the PbO nanoparticles was still visible in a TEM, using the process diffraction method. Both XRD and SAED proved to be useful for the evaluation of the results of the milling process and compaction.     

Data-Intensive Computing in the 21st Century

The deluge of data that future applications must process—in domains ranging from science to business informatics—creates a compelling argument for substantially increased R&D targeted at discovering scalable hardware and software solutions for data-intensive problems.     

Control of Drying Process in Mechanically Spouted Bed Dryer

ABSTRACT

The continuously operated Mechanically Spouted Bed (MSB) dryer of high evaporative capacity can be advantageously used to produce fine powder from paste-like materials, slurries, suspensions and sludges. Due to the thin layer formed on the surface of the spherical inert particles intensive heat and mass transfer occur and the drying process takes place in the constant rate period. Steady state drying conditions can be achieved when the total operational time of partial processes of inert bed drying does not exceed the cycle time of the inert particles.

A laboratory scale MSB dryer has been equipped with a computerised measuring, data acquisition and control system. In the knowledge of the hydrodynamic characteristics of the MSB and giving the enthalpy and mass balances over the dryer a calculation method has been developed for control of drying process.     

Evolution or revolution: where next for impact assessment?

Impact assessment (IA) has become one of the most prevalent environmental policy instruments today. Its introduction under the National Environmental Policy Act (US) in 1969 was revolutionary. Perhaps it is not surprising, then, that such a widely used tool has received its share of criticism, including that it fails to meet some of its fundamental goals. Over the last fifty years, IA has broadened in scope and application and embraced new techniques. It has followed evolved, but has not changed fundamentally.

We believe that IA must continue to change to meet the societal and environmental challenges of the 21^st century. But will it be enough for IA to progress through incremental change (evolution), or is a complete overhaul of impact assessment (revolution) needed? We provide some ideas as to what ‘evolution’ and ‘revolution’ may look like, but rather then offering a definitive way forward now, we invite stakeholders to present their thoughts and suggestions at the IAIA19 Annual Conference in Brisbane, which carries the same theme as the title of this article.     

Real-time determination of cutting force coefficients without cutting geometry restriction

The determination of the cutting force coefficients is a critical point in the case of using the mechanistic cutting force model for predicting the forces during milling processes. The main reason is that the computations require a series of experiments with special geometrical conditions, and the validity of the results is limited. In this paper a cutting force predicting method, based on the mechanistic cutting force model will be introduced, together with an algorithm for determining the cutting force coefficients in the course of a single experiment without restrictions in regard to the cutting geometry. Besides the fact that the proposed method lifts the geometrical restrictions of the previously published solutions, it makes it possible to calculate the coefficients just when they are needed for force prediction right at the machining process, to avoid the problem of the limited validity of the coefficients. In this case the real-time measuring of the cutting forces is needed, while the forthcoming forces can be predicted with an appropriate look-forward algorithm, which is also presented.     

Principles for Hydrodynamical and Geometrical Design of Vibrated Bed Driers

ABSTRACT

Processing in vibrated beds is characterized by the versatility and the easy controlability through parameters of vibration (amplitude, frequency and intensity). The main task of the control of processing is the synchronization of the residence time of particles in the processing area with the duration of drying. The drying time depends on the physical properties of the processed material, on the thermal parameters of the bed and on the operational parameters. The residence time depends on the mechanical properties of the particles, on the intensity of transport and on the eometrical parameters of the equipment. Since most of the parameters of the vibrational processing depend on the intensity of vibration, synchronization of the drying time with the residence time of particles, optimization of the process and optimal design of the vibrational equipment in general must be performed by the control of this operational parameter. Therefore a sophisticated algorithm and software for optimal control and design of vibrational processing equipment is needed. Such an algorithm based on the "Classification Scheme of Vibrated Systems" is described in this paper. The design algorithm has been tested using experimental data measured in a laboratory scale aerovibrofluidized bed dryer.     

Prediction of homology and divergence in the secondary structure of polypeptides

A quantitative procedure is described for the comparison of secondary structure of homologous proteins. Standard predictive methods are used to generate probability profiles from pairs of homologous amino acid sequences; correlation coefficients (R) are then computed between each pair of amino acids for alpha-helix (R alpha), extended structure (R beta), turn (R(t)), and coil (R(c)). R values are >0.2 for correctly aligned homologous sequences. Unrelated or incorrectly aligned sequences give R values near zero. Lack of correlation for a segment of otherwise well-correlated sequences is used to identify structural divergence, which is then evaluated graphically by using difference profiles. A combination of these techniques correctly predicts secondary structural differences between melittin or beta-endorphin and their respective synthetic analogs. The method is potentially useful to describe evolutionary changes in protein secondary structure as well as in the design of peptide analogs.