New Technique For Design Research Articles

Novel polyoxometalate-based composite as efficient electrocatalyst for alkaline water oxidation reaction

The development of new techniques for design and fabrication of efficient and durable electrocatalysts for water splitting into hydrogen and oxygen is a fundamental approach to one of the major challenges to meet future sustainable fuel demand. Herein, a novel polyoxometalate-based composite was formed onto rotating carbon paste electrode by two different immobilization techniques, including physical mixing method and direct formation method, and used as electrocatalysts for the oxygen evolution reaction (OER) in alkaline media. The comparisons of the electrochemical performance of these fabrication methods exhibited a high catalytic activity and stability toward OER for both immobilization techniques and gained a current density of 10 mA cm−2 at overpotential of 380 and 440 mV for direct formation and physical mixing methods, respectively.

Three-Stage Feedback Controller Design With Applications to Three Time-Scale Linear Control Systems

This paper presents a new technique for design of full-state feedback controllers for linear dynamic systems in three stages. The new technique is based on appropriate partitioning of the linear dynamic system into linear dynamic subsystems. Every controller design stage is done at the subsystem level using only information about the subsystem (reduced-order) matrices. Due to independent design in each stage, different subsystem controllers can be designed to control different subsystems. Partial subsystem level optimality and partial eigenvalue subsystem assignment can be achieved. Using different feedback controllers to control different subsystems of a system has not been present in any other known linear full-state feedback controller design technique. The new technique requires only solutions of reduced-order subsystem level algebraic equations. No additional assumptions were imposed except what is common in linear feedback control theory (the system is controllable (stabilizable)) and theory of three time-scale linear systems (the fastest subsystem state matrix is invertible)). The local full-state feedback controllers are combined to form a global full-state controller for the system under consideration. The presented results are specialized to the three time-scale linear control systems that have natural decomposition into slow, fast, and very fast subsystems, for which numerical ill conditioning is removed and solutions of the design algebraic equations are easily obtained. The proposed three-stage three time-scale feedback controller technique is demonstrated on the eighth-order model of a fuel cell model.

Sound concentration caused by curved surfaces

In room acoustics, the focusing effect of reflections from concave surfaces is a well-known problem. The occurrence of concave surfaces has tended to increase in modern architecture, due to new techniques in design, materials, and manufacturing. Focusing can cause high sound pressure levels, sound coloration, or an echo. Although the problem is well known, the amount of amplification that occurs in the focusing point and the sound field around the focusing point are not. The pressure in the focusing point can only be calculated using wave-based methods. An engineering method that is based on the Kirchhoff Integral is presented to approximate the reflected sound field in and around the focusing point for a few basic geometries. It will be shown that both the amplification and the area of the focusing is strongly related to wavelength. The focusing caused by surfaces that are curved in two directions (sphere, ellipsoid) is much stronger than that caused by surfaces that are curved in only one direction (cylinders). This method enables designers to evaluate and thereby improve or redesign the geometry. The method is illustrated with a few examples.

Design, Preparation and Characterization of Self‐Reinforced Starch Films through Chemical Modification

AbstractA new technique for design and preparation of self‐reinforced starch films is introduced. The films were based on a high‐amylose corn starch that was chemically modified in different ways. Hydroxypropylation was used to decrease gelatinization temperature and improve processability. The reinforcing component consisted of cross‐linked starch granules, where the crosslinking increased granule thermal stability and moisture resistance. Distribution of the cross‐linked starch was imaged by CLSM, and the matrix/particle interface was studied by SEM. Modulus and tensile properties of the starch film were increased by about 30 and 20%, respectively, after addition of rigid cross‐linked starch particles. A perfect interface between matrix and reinforce agent was obtained. magnified image

An Input Shaping Filter

The method of control signal shaping has been practically used in control systems with flexible elements since the end of 80th years of last century. The most of applications has been focused on machine engineering, e. g. speedy elevators, cranes, etc. New techniques for design of train of impulses improving system robustness appeared in the theory (mainly in time domain). The article presents alternative approach based on discrete shaping filter design as a correction filter with impulse response identical to classical solution (for properly selected filter parameters). Referring to realization of control signal shaping system by digital devices, this approach is more convenient one. The proposed modification, increasing of sampling frequency at the input of digital shaping filter, allows fast system response to control signal changes.

A New Technique for Design of Low-Profile, Second-Order, Bandpass Frequency Selective Surfaces

In this study, a new method for designing low profile frequency selective surfaces (FSS) with second-order bandpass responses is presented. The FSSs designed using this technique utilize non-resonant subwavelength constituting unit cells with unit cell dimensions and periodicities in the order of 0.15lambda <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> . It is demonstrated that using the proposed technique, second-order FSSs with an overall thickness of lambda <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> /30 can be designed. This is considerably smaller than the thickness of second-order FSSs designed using traditional techniques and could be particularly useful at lower frequencies with long wavelengths. To facilitate the design of this structure, an equivalent circuit based synthesis method is also presented in this paper. Two bandpass FSS prototypes operating at X-band are designed, fabricated, and tested. A free space measurement setup is used to thoroughly characterize the frequency responses of these prototypes for both the TE and TM polarizations and various angles of incidence. The frequency responses of these structures are shown to have a relatively low sensitivity to the angle of incidence. Principles of operation, detailed design and synthesis procedure, and measurement results of two fabricated prototypes are presented and discussed in this paper.

The Ellipsoidal Technique for Design Centering of Microwave Circuits Exploiting Space-Mapping Interpolating Surrogates

A new technique for design centering of microwave circuits is introduced. This technique exploits the space-mapping interpolating surrogate (SMIS) with a modified ellipsoidal technique. The design centering solution for microwave circuits is obtained with a small number of fine model evaluations and, hence, the number of electromagnetic simulations is greatly reduced. Practical and demonstrative examples are included to show the efficiency of the new technique.

Neurogenetic Design Centering

A new technique for design centering and yield enhancement of devices and circuits is presented. The proposed method uses neural networks for device and/or circuit modeling and genetic algorithms for parametric yield optimization. It uses a Monte Carlo-based method for yield estimation via the neural models (thus consuming less time) and genetic algorithms for efficient design centering. The neurogenetic methodology has been used for design centering of SiGe heterojunction transistors and millimeter-wave voltage controlled oscillators. It results in significant yield enhancement of the SiGe heterojunction bipolar transistors (from 25% to 75%) and voltage controlled oscillators (from 8 % to 85 %). To the best of our knowledge, this method has not been reported previously.

Visual product evaluation: exploring users’ emotional relationships with products

This paper discusses an industrial designer's approach to eliciting user perceptions and emotional responses to products through visual evaluation and stimuli. Whilst the authors accept that product functionality is crucial for product success, the appearance, use of materials, shape and form provide the most immediate product data for the user. Less tangible issues such as emotional bonding of users with products, cultural perceptions and social value systems, provide valuable insights for the product developer to help expand knowledge and understanding of the users’ need beyond the functional. This paper presents product personality profiling as a new technique for design researchers/designers, and discusses it alongside other emerging approaches such as mood boards and visual product evaluation. The authors have used these techniques during focus group sessions with users to elicit individuals’ needs and aspirations towards products. Such a user-centred approach is fundamental to applied ergonomics. Experiences, benefits, and limitations of these techniques are outlined as well as the opportunities for further development.

A computer-based intelligent system for Design for Assembly

A computer-based intelligent system for Design for Assembly (DFA) within a concurrent engineering environment is presented in this article. The main objective of the current research work is to develop an expert system that supports new techniques for design for assembly and to give users the possibility to assess and reduce the total production cost at an early stage during the design process. The system enables designers to minimise the number of components of a product and select the most economic assembly technique for that specific product.

Project-Specific Software for Offshore Emergency Shutdown Systems

New legislation following the Piper Alpha disaster has highlighted the unsatisfactory state of programmable equipment system (PES)-based emergency shutdown (ESD) systems for offshore installations. As in the nuclear generation industry, concern is being expressed for the quality of software, particularly project-specific or application software for these systems. The defence-in-depth approach adopted by the nuclear industry is impracticable for the offshore industry and new techniques for design and implementation of the project-specific software of ESD systems are urgently required.

Convexity-based algorithms for design centering

A new technique for design centering and polytope approximation of the feasible region for a design are presented. In the first phase, the feasible region is approximated by a convex polytope, using a method based on a theorem on convex sets. As a natural consequence of this approach, a good approximation to the design center is obtained. In the next phase, the exact design center is estimated using one of two techniques that we present in this paper. The first inscribes the largest Hessian ellipsoid, which is known to be a good approximation to the shape of the polytope, within the polytope. This represents an improvement over previous methods, such as simplicial approximation, where a hypersphere or a crudely estimated ellipsoid is inscribed within the approximating polytope. However, when the probability density functions of the design parameters are known, the design center does not necessarily correspond to the center of the largest inscribed ellipsoid. Hence, a second technique is developed that incorporates the probability distributions of the parameters, under the assumption that their variation is modeled by Gaussian probability distributions. The problem is formulated as a convex programming problem and an efficient algorithm is used to calculate the design center, using fast and efficient Monte Carlo methods to estimate the yield gradient. An example is provided to illustrate how ellipsoid-based methods fail to incorporate the probability density functions and is solved using the convex programming-based algorithm.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Design of separable‐denominator two‐dimensional digital filters based on the reduced‐dimensional decomposition of frequency domain specifications

AbstractThis paper proposes a new technique for design of separable‐denominator two‐dimensional digital filters (2DDF·s) in the frequency domain. The technique is based on decomposing both the transfer function of a separable‐denominator 2DDF and the given 2DDF frequency domain specification into a product of two one‐dimensional ones. By these decompositions, the design problem of a separable‐denominator 2DDF can be reduced to the design of two IDDF·s. The technique makes it possible to design separable‐denominator 2DDF·s by utilizing IDDF design techniques directly. Thus stable separable‐denominatro 2DD·s satisfying the given specifications can be designed efficiently.

A new way of generating the nyquist spectral‐shaped high‐speed and multilevel digital signals

AbstractHigh‐speed waveform transmission is of great importance in the realization of digital radio systems with high spectrum utilization efficiency. the binary transversal filter (BTF) offers an effective technique for achieving high‐precision waveform generation because it is a means of producing the desired waveform directly in the time domain. This paper presents a new technique for design of the BTF and discusses the authors' experimental results. the new BTF can be applied quite easily to high‐speed multilevel signals and is composed of a shift register, a programmable ROM (PROM) and a D/A converter which are driven by a multiphase clock. A was used to design the basic parameters of the BTF: sampling frequency, number of taps and tap coefficients, quantization levels for the D/A converter and allowable phase error for the clock signal. an analysis was conducted to determine the effect that each factor has the spectral characteristics and intersymbol interference characteristics. Further it was shown that based on this configuration and design method, a 12.5‐MB 4‐level Nyquist waveform can be realized without adjustment.

Design of ARMA digital filters by pole-zero decomposition

A new technique for design of digital filters is presented in this paper. The technique exploits the spectral approximation property of autoregressive modeling to reduce ripple at the edges of the transition band in the filter response. An autoregressive model approximates a given spectrum better at the peaks than at the Valleys. Spectral information around the transition band is transformed into peaks by splitting the given squared-magnitude frequency response into two component spectra. This splitting is accomplished using a pole-zero decomposition technique, which in turn uses the properties of the derivative of phase spectrum of minimum phase filters. One of the component spectra corresponds nearly to the response of an all-pole filter, and the other component spectrum corresponds nearly to the response of an all-zero filter. Each of these corresponends spectra can be represented by a small number of coefficients using autoregressive modeling. The resulting two sets of autoregressive coefficients determine poles and zeros of the autoregressive moving average (ARMA) digital filter. Ripple characteristics in the response of the ARMA filter can be controlled by appropriately choosing the number of poles and zeros. It is shown that a wide variety of magnitude frequency response characteristics can be approximated by an ARMA filter of low order using this technique. The technique does not work well in cases where spectral approximation by autoregressive modeling is poor. Such cases arise when the component spectra have very large dynamic range.

Fifty-Year Development — Construction of Steel Pipeline Suspension Bridges

Pipeline suspension bridge construction has evolved from short or multispan structures to long single-span structures with the development of new techniques in design, fabrication, and erection. These developments are examined by reviewing the construction of representative bridges which have been built in the United States and of one unique Canadian bridge.