Post-industrial robotics: the new tendency of digital fabrication for exploring responsive forms and materials through performance

The contribution proposes the experimental results of research on robotics manufacturing issues for the realization of informed architectural organisms on a 1:1 scale. The pavilions Fusta Robotics and Digital Urban Orchard and the technological system In.Flux represent the results of tests in which material, environmental and structural performance inform the computational process and the consequent materialization. The two pavilions, both wooden, constitute the physical implementation of different functional programs realised through a collaboration with industrial partners. Fusta Robotics is the result of a collaboration between industry and universities for the tectonic experimentation derived from the use of local non-engineered material. Digital Urban Orchard is the formal expression of a complex functional program arising from the relationship amongst form (shape), function and context for a new concept of socialization space and food production within the agenda at the self-sufficiency in Barcelona. Finally, through the In.Flux prototype, we investigated the relationship among formal generation, structural analysis and robotic manufacturing for the realization of concrete free-form structures. The analysis of the prototypes opens the debate on the role of IT in the post-digital era when the design process manifest through the control and management of the flow of information affecting the digital computation and fabrication and the material behaviour. The resulting theoretical assumption considers the architectural form as the result of a diagram of forces where the achievement of the performance is the driving parameter for the formal geometric exploration. The continuous variation resulting therefrom is informed by performance parameters that define a new aesthetic which represents together the manifestation of objectively measurable performance parameters and the power of the tool through which the form is generated

A stability condition for turbulence model: From EMMS model to EMMS-based turbulence model

The closure problem of turbulence is still a challenging issue in turbulence modeling. In this work, a stability condition is used to close turbulence. Specifically, we regard single-phase flow as a mixture of turbulent and non-turbulent fluids, separating the structure of turbulence. Subsequently, according to the picture of the turbulent eddy cascade, the energy contained in turbulent flow is decomposed into different parts and then quantified. A turbulence stability condition, similar to the principle of the energy-minimization multi-scale (EMMS) model for gas-solid systems, is formulated to close the dynamic constraint equations of turbulence, allowing the heterogeneous structural parameters of turbulence to be optimized. We call this model the `EMMS-based turbulence model', and use it to construct the corresponding turbulent viscosity coefficient. To validate the EMMS-based turbulence model, it is used to simulate two classical benchmark problems, lid-driven cavity flow and turbulent flow with forced convection in an empty room. The numerical results show that the EMMS-based turbulence model improves the accuracy of turbulence modeling due to it considers the principle of compromise in competition between viscosity and inertia.Comment: 26 pages, 13 figures, 2 table

Modeling and Optimization of Lactic Acid Synthesis by the Alkaline Degradation of Fructose in a Batch Reactor

The present work deals with the determination of the optimal operating conditions of lactic acid synthesis by the alkaline degradation of fructose. It is a complex transformation for which detailed knowledge is not available. It is carried out in a batch or semi-batch reactor. The ‘‘Tendency Modeling’’ approach, which consists of the development of an approximate stoichiometric and kinetic model, has been used. An experimental planning method has been utilized as the database for model development. The application of the experimental planning methodology allows comparison between the experimental and model response. The model is then used in an optimization procedure to compute the optimal process. The optimal control problem is converted into a nonlinear programming problem solved using the sequencial quadratic programming procedure coupled with the golden search method. The strategy developed allows simultaneously optimizing the different variables, which may be constrained. The validity of the methodology is illustrated by the determination of the optimal operating conditions of lactic acid production

A Method for Optimizing Chemical Composition of Steels to Reduce Radically Their Alloy Elements and Increase Service Life of Machine Components

A method for optimizing chemical composition of steel is proposed and a correlation is established to reduce cardinally alloy elements in existing steel grades that results in high compressive residual stresses at the surface of intensively quenched steel parts and increasing strength and ductility of material due to super- strengthening phenomenon. The algorithm of optimization consists in reducing alloy elements in existing alloy steel in 1.5 – 2 times and then lowering step-by-step content of steel, beginning from the most costly alloy element and ending the most cheaper one, until established correlation is satisfied. The range of reduction is minimal and during computer calculations can be chosen as 0,001wt%. The proposed approach can save alloy elements, energy, increase service life of machine components and improve environmental condition. The method is a basis for development of the new low hardenability (LH) and optimal hardenability (OH) steels

Review on Blueprint of Designing Anti-Wetting Polymeric Membrane Surfaces for Enhanced Membrane Distillation Performance

Recently, membrane distillation (MD) has emerged as a versatile technology for treating saline water and industrial wastewater. However, the long-term use of MD wets the polymeric membrane and prevents the membrane from working as a semi-permeable barrier. Currently, the concept of antiwetting interfaces has been utilized for reducing the wetting issue of MD. This review paper discusses the fundamentals and roles of surface energy and hierarchical structures on both the hydrophobic characteristics and wetting tolerance of MD membranes. Designing stable antiwetting interfaces with their basic working principle is illustrated with high scientific discussions. The capability of antiwetting surfaces in terms of their self-cleaning properties has also been demonstrated. This comprehensive review paper can be utilized as the fundamental basis for developing antiwetting surfaces to minimize fouling, as well as the wetting issue in the MD process

Conditions for the growth of smooth La0.7Sr0.3MnO3 thin films by pulsed electron ablation

We report on the optimisation of the growth conditions of manganite La0.7Sr0.3MnO3 (LSMO) thin films prepared by Channel Spark Ablation (CSA). CSA belongs to pulsed electron deposition methods and its energetic and deposition parameters are quite similar to those of pulsed laser deposition. The method has been already proven to provide manganite films with good magnetic properties, but the films were generally relatively rough (a few nm coarseness). Here we show that increasing the oxygen deposition pressure with respect to previously used regimes, reduces the surface roughness down to unit cell size while maintaining a robust magnetism. We analyse in detail the effect of other deposition parameters, like accelerating voltage, discharging energy, and temperature and provide on this basis a set of optimal conditions for the growth of atomically flat films. The thicknesses for which atomically flat surface was achieved is as high as about 10-20 nm, corresponding to films with room temperature magnetism. We believe such magnetic layers represent appealing and suitable electrodes for various spintronic devices.Comment: original paper, thin film optimization, 25 pages, 9 figure

Intramolecular Torque, an Indicator of the Internal Rotation Direction of Rotor Molecules and Similar Systems

Torque is ubiquitous in many molecular systems, including collisions, chemical reactions, vibrations, electronic excitations and especially rotor molecules. We present a straightforward theoretical method based on forces acting on atoms and obtained from atomistic quantum mechanics calculations, to quickly and qualitatively determine whether a molecule or sub-unit thereof has a tendency to rotation and, if so, around which axis and in which sense: clockwise or counterclockwise. The method also indicates which atoms, if any, are predominant in causing the rotation. Our computational approach can in general efficiently provide insights into the rotational ability of many molecules and help to theoretically screen or modify them in advance of experiments or before analyzing their rotational behavior in more detail with more extensive computations guided by the results from the torque approach. As an example, we demonstrate the effectiveness of the approach using a specific light-driven molecular rotary motor which was successfully synthesized and analyzed in prior experiments and simulations.Comment: 11 pages, 4 figures, 1 SI fil

Pembinaan dan penilaian program rekabentuk rasuk keluli (PRRK) sebagai alat kognitif dalam pembelajaran rekabentuk struktur di kalangan pelajar diploma kejuruteraan awam KUiTTHO

Kajian awal yang telah dijalankan mendapati pelajar Kejuruteraan Awam KUiTTHO menghadapi masalah kognitif dalam pembelajaran mata pelajaran Rekabentuk Struktur khasnya dalam pemahaman konsep dan prosedur reka bentuk. Langkah pengiraan yang terlalu banyak selalunya mengelirukan pelajar sehinggakan mereka hilang minat dan tumpuan. Bagi membantu mereka, satu program telah disediakan dengan menggunakan perisian Microsoft Excel bagi tujuan menganalisis dan mereka bentuk rasuk keluli bagi meningkatkan tahap kemahiran kognitif terhadap matapelajaran tersebut. Program Rekabentuk Rasuk Keluli (PRRK) ini disediakan berdasarkan kaedah reka bentuk yang diamalkan oleh British Standard Institution, Structural Use of Steel Work In Building. Seramai dua puluh satu orang pelajar semester akhir Diploma Kejuruteraan A warn yang mengambil mata pelajaran Rekabentuk Struktur telah diminta menilai program ini. Penilaian telah dijalankan terhadap isi, sifat mesra pengguna dan kebolehlaksanaan program menggunakan kaedah skor min. Selain itu perkaitan antara pengalaman pelajar menggunakan komputer sebagai sumber pembelajaran dengan penilaian PRRK juga telah dilihat. Keputusan skor min menunjukkan isi PRKK adalah baik, bersifat mesra pengguna dan mempunyai sifat kebolehlaksanaan. Ujian korelasi Spearman pula menunjukkan bahawa tidak terdapat sebarang perkaitan yang signifikan di antara pengalaman pelajar menggunakan komputer sebagai sumber pembelajaran dengan penilaian PRRK