Simple Design Approach Research Articles

Unique Roll-Off Roof for Housing 1.3 m Telescope at Devasthal, Nainital

Aryabhatta Research Institute of Observational Sciences (ARIES) had set up a 1.3 m telescope at Devasthal, Nainital, India in the year 2010. Country’s largest roll-off roof was indigenously designed, fabricated and installed on top of a building (17 × 8 m) for housing 1.3 m telescope. Telescope was supplied by M/s DFM Engineering Inc., USA to ARIES and was installed in the building with unique roll-off roof to protect it from external environment. Roll-off roof was designed and fabricated considering various parameters and available manpower and resources at ARIES. This paper presents mechanical development work, simple but distinct design approach and innovative selection of materials to economically manufacture roll-off roof of large size (8 × 8 × 4 m) at hilly remote site of Devasthal situated in Central Himalayan region. All operations in the roof viz. opening of shutters and rolling of roof were motorized to facilitate observers during night observations.

Full-Color Subwavelength Printing with Gap-Plasmonic Optical Antennas.

Metallic nanostructures can be designed to effectively reflect different colors at deep-subwavelength scales. Such color manipulation is attractive for applications such as subwavelength color printing; however, challenges remain in creating saturated colors with a general and intuitive design rule. Here, we propose a simple design approach based on all-aluminum gap-plasmonic nanoantennas, which is capable of designing colors using knowledge of the optical properties of the individual antennas. We demonstrate that the individual-antenna properties that feature strong light absorption at two distinct frequencies can be encoded into a single subwavelength-pixel, enabling the creation of saturated colors, as well as a dark color in reflection, at the optical diffraction limit. The suitability of the designed color pixels for subwavelength printing applications is demonstrated by showing microscopic letters in color, the incident polarization and angle insensitivity, and color durability. Coupled with the low cost and long-term stability of aluminum, the proposed design strategy could be useful in creating microscale images for security purposes, high-density optical data storage, and nanoscale optical elements.

Compact UWB bandpass filter based on simple radial stub resonator structure

In this letter, a new compact microstrip ultra-wideband (UWB) bandpass filter (BPF) is proposed. Using a new electrical model leading to a simple structure based on radial stub resonator (RSR), its originality resides in its noteworthy simple design approach where the filter response can be accurately adjusted by tuning three parameters only. The fabricated filter shows a good agreement between simulations and measurements whereas fulfilling UWB requirements, i.e., enhanced selectivity, good matching and flatness within the entire band of operation, and sufficiently constant group delay. With an overall size of 9.53 mm x 8.28 mm, a high compactness has been achieved, making this structure one of the most compact filters ever reported. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1707–1710, 2016

Two-degree-of-freedom fractional order-PID controllers design for fractional order processes with dead-time

Recently, fractional order (FO) processes with dead-time have attracted more and more attention of many researchers in control field, but FO-PID controllers design techniques available for the FO processes with dead-time suffer from lack of direct systematic approaches. In this paper, a simple design and parameters tuning approach of two-degree-of-freedom (2-DOF) FO-PID controller based on internal model control (IMC) is proposed for FO processes with dead-time, conventional one-degree-of-freedom control exhibited the shortcoming of coupling of robustness and dynamic response performance. 2-DOF control can overcome the above weakness which means it realizes decoupling of robustness and dynamic performance from each other. The adjustable parameter η2 of FO-PID controller is directly related to the robustness of closed-loop system, and the analytical expression is given between the maximum sensitivity specification Ms and parameters η2. In addition, according to the dynamic performance requirement of the practical system, the parameters η1 can also be selected easily. By approximating the dead-time term of the process model with the first-order Padé or Taylor series, the expressions for 2-DOF FO-PID controller parameters are derived for three classes of FO processes with dead-time. Moreover, compared with other methods, the proposed method is simple and easy to implement. Finally, the simulation results are given to illustrate the effectiveness of this method.

Production of Controlled Low Strength Material Utilizing Waste Paper Sludge Ash and Recycled Aggregate Concrete

Recently, the best method to make the concrete industry more sustainable was using the waste materials to replace the natural resources. Currently waste paper sludge is a major economic and environmental problem in this country. In this research, the alternative method is to dwindle the usage of natural resources and the usage of cement in the construction. This method is to replace the usage of cement with the waste paper sludge ash (WPSA) and to use the recycle aggregate collected from the construction is used. The WPSA has ingredient likely cement such as self-cementation but for a low strength. The research was conducted at heavy laboratory UITM Pulau Pinang. Meanwhile, the WPSA is collected at MNI Industries at Mentakab, Pahang. The recycle aggregate is a separated half, which were fine aggregate and the coarse aggregate with the specific size. In this research, the ratio is divided into two (2) which is 1:1 and 1:2 for the aggregate and difference percentage levels of WPSA. The percentage levels of WPSA that use in this research are 10%, 20%, 30%, 40%, 50%, and 60%. A total of 36 cubes were prepared. Aim of this research is to develop a simple design approach for the mixture proportioning of WPSA and recycle concrete aggregate (RCA) within the concrete and to assess the effect of concrete mix with different percentage of WPSA and RCA ratio on the properties. It is found that the best design mix that achieves control low strength material (CLSM) is on 30% of WPSA with the ratio 1:2 on day 28 of compression test.

Analysis of a dual-twist Pancharatnam phase device with ultrahigh-efficiency large-angle optical beam steering.

It has been previously shown that a Pancharatnam phase device with a dual-twist structure can deflect light up to 60° with nearly perfect efficiency. This was beyond the limits previously assumed for these types of devices, which were considered to be optically similar to Raman-Nath gratings. In this paper we first consider the range of parameters that will allow for high efficiency and show the results for a structure that demonstrates 80° deflection. We then explore the light propagation through these devices to point out interesting intensity variations in the deflected mode of light as it traverses the deflecting layer. Finally, we explain the key to understanding the efficiency of these devices, which is not the typical parameters that are important for traditional diffractive devices, but rather the control of the polarization state of light. We provide a simple design approach for optimizing the twist angle and retardation for high efficiency.

Simple Design Criterion for Residual Energy on Embankment Dam Stepped Spillways

AbstractThe stepped spillway design is associated with significant flow resistance and associated energy dissipation on the steps, yielding smaller, more economical downstream dissipation structures. A number of design guidelines were developed for steep stepped spillways typical of concrete gravity dams. The focus of this study is on embankment stepped spillways. A large set of air-water flow data is compared with reanalyzed data sets to provide a simple unifying design approach for the residual energy at the stepped chute’s downstream end and to highlight the uncertainties involved. The results provided some simple design criteria in terms of the dimensionless residual energy of stepped chutes with flat steps. It is believed that a stepped design with a 1V:2.5H slope (θ=21.8°) might be optimum in terms of energy dissipation performances. The Darcy-Weisbach friction factors were close for all stepped data ranging between 0.1≤fe≤0.4.

A general approach for rational design of fluorescent DNA aptazyme sensors based on target-induced unfolding of DNA hairpins

DNA aptazymes are allosteric DNAzymes activated by the targets of DNA aptamers. They take the advantages of both aptamers and DNAzymes, which can recognize specific targets with high selectivity and catalyze multiple-turnover reactions for signal amplification, respectively, and have shown their great promise in many analytical applications. So far, however, the available examples of DNA aptazyme sensors are still limited in utilizing only several DNAzymes and DNA aptamers, most likely due to the lack of a general and simple approach for rational design. Herein, we have developed such a general approach for designing fluorescent DNA aptazyme sensors. In this approach, aptamers and DNAzymes are connected at the ends to avoid any change in their original sequences, therefore enabling the general use of different aptamers and DNAzymes in the design. Upon activation of the aptazymes by the targets of interest, the rate of fluorescence enhancement via the cleavage of a dually labeled substrate by the active aptazymes is then monitored for target quantification. Two DNAzymes and two aptamers are used as examples for the design of three fluorescent aptazyme sensors, and they all show high selectivity and sensitivity for the detection of their targets. More DNA aptazyme sensors for a broader range of targets could be developed by this general approach as long as suitable DNAzymes and aptamers are used.

Semiotic Analysis of E-Newspapers Interface Views within the Scope of Advertisements

Interface of a website is a designed and composed space and it is like a paper to be filled with visual and inscriptive data. Advertisements on newspapers can reach to readers both by physical and virtual space. As district from traditional techniques, online advertisements realize presentation functions by the fee for taking place on web pages without any paper or print cost. However, with today's revised advertising policy laws, due to enhance of advertising spaces, the main information and images are almost stuck between the advertisements on webpage of enewspapers. On the web interfaces of e-newspapers, almost half of the page is covered with advertisements without attention of design principles. In this context, with the purpose of arranging web pages more appropriately to the design principles and transferring actual information to the readers with more simple design approach the selected newspapers’ web interfaces will be discussed with semiotics.

Fourth‐order dual mode substrate integrated waveguide filter

ABSTRACTIn this letter, a simple approach for design and realization of dual mode substrate integrated waveguide (SIW) bandpass filter of order higher than two is presented. The dual mode resonators are square SIW cavities perturbed by corner cut perturbation. In the coupling configuration of the proposed filter, the odd and even modes of the perturbed cavities are used as basis modes. Different paths are provided for the odd modes and the even modes from input to output port and, therefore, the sensitivity of filter with respect to the fabrication tolerance is reduced. Using this approach, a fourth‐order dual mode bandpass filter is designed and realized and a filter prototype is fabricated on a single layer substrate using PCB technology. The measured results are in a good agreement with the simulated results. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1550–1553, 2015

Analysis and compensation of hysteresis of PZT micro-actuator used in high precision dual-stage servo system

Piezoelectric micro–actuator made from (PZT) has been a suitable choice as the secondary actuator of a dual–stage actuator system. However, like any other piezoelectric actuator, this secondary PZT micro–actuator also exhibits hysteresis which is the inherent nonlinearity characteristic of piezoelectric material. Therefore, the advantage gained by the precision of secondary actuator is somewhat lost by this hysteresis, if not compensated. This paper proposes a rigorous technique for analysing, identifying and compensating the hysteresis of PZT actuator used in dual–stage actuator system. Identification and compensation are the two parts of the paper. In the first part of the paper, the parameters of generalised Prandtl–Ishlinskii (GPI) model are identified offline by particle swarm optimisation (PSO) technique. In compensation part, inverse GPI as the hysteresis compensator is obtained from the identified hysteresis model. Then in case of parameter uncertainty, PSO–based online tuning method is employed to adaptively adjust the parameters of inverse GPI model. For the linear controller of dual–stage, a simple design approach is followed. Simulation results show that the proposed technique can be efficiently used for the identification and compensation of hysteresis of PZT micro–actuator.

A Fast Geometric Optics-Based Design Approach for Dielectric Rod Antennas

A simple and effective dielectric rod antenna design approach based on geometric optics and modal analysis is presented. The tapered antennas from microwave to terahertz can be readily designed with the equations presented in this paper. The radius of antenna is determined by the desired traveling wave mode inside the antenna. The field inside the antenna consists of the fundamental mode and the second mode. For the end-fire operation, there is only the fundamental mode. The length of the antenna is designed based on geometric optics theory so that most of the traveling wave will be converted to the radiating field towards the output plane, avoiding reflection inside the antenna. Such antennas can achieve wide bandwidth. The gain increases with the length of the antenna as long as the diameters and length satisfy the conditions given in this paper. A number of antenna design examples with high gain and wide bandwidth are presented. The measurement results of a 130 GHz rectangular antenna with a length of 4λshow a bandwidth of 60 GHz and a gain of 12 dB.

Effect of Seismic Load History on Deformation Limit States for Longitudinal Bar Buckling in RC Circular Columns

This paper investigates the impact of seismic load history on longitudinal bar buckling in reinforced concrete (RC) bridge columns. Previous research has shown that reinforcing bars are prone to buckling upon reversal from tensile strain. To quantify this effect, a hybrid analysis method using both fiber and solid elements is developed and implemented to assess the impact of seismic load history on reinforcing bar buckling. Forty earthquake ground motions are utilized to conduct nonlinear time history analysis of bridge columns using a fiber-based model. The longitudinal bar strain history from the fiber-based model is then utilized as the input to the finite element model. A parametric study is conducted for the purpose of developing design equations that provide strain limits prior to the onset of bar buckling. Simple design approaches are proposed based on the design equations.

A multinotched octagonal shaped fractal UWB antenna

ABSTRACTIn this article, a simple design approach for small ultrawideband (UWB) antenna is presented. The small size and wideband operability is obtained by introducing Minkowski like fractal geometry in the design. It is observed that addition of fractal elements at the edges of octagonal shape leads to wideband phenomena. Furthermore, the insertion of multiple notches in the ground plane improves return loss characteristic in the desired UWB operational bandwidth of 3.1–10.6 GHz. The compact 16.5 × 13.5 mm2 antenna geometry size exhibits nearly omnidirectional radiation pattern, with VSWR < 2 over the entire UWB frequency range. The optimized antenna is fabricated and measured using vector network analyzer. The measured characteristics are in good agreement with the simulated one. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2469–2473, 2014

Ku-band 200-W Pulsed Power Amplifier Based on Waveguide Spatially Power-Combining Technique for Industrial Applications

A Ku-band 200-W pulsed solid-state power amplifier has been presented and designed by using a hybrid radial-/rectangular-waveguide spatially power-combining technique. The hybrid radial-/rectangular-waveguide power-dividing/power-combining circuit employed in this design provides not only a high power-combining efficiency over a wide bandwidth but also efficient heat sinking for the active power devices. A simple design approach of the presented power-dividing/power-combining structure has been developed. The measured small-signal gain of the pulsed power amplifier is about 51.3 dB over the operating frequency range, while the measured maximum output power at 1-dB compression is 209 W at 13.9 GHz, with an active power-combining efficiency of about 91%. Furthermore, the active power-combining efficiency is greater than 82% from 13.75 to 14.5 GHz.

Synthesis and Properties of Core–Shell Metal–Ceramic Microstructures and their Application as Heterogeneous Catalysts

AbstractA facile synthesis of core–shell metal–ceramic microcomposites with unique structural and chemical properties and their superior performance as heterogeneous catalysts are reported. These core–shell microstructures were prepared by hydrothermal surface oxidation of Al particles in water with or without the presence of heterometal species followed by calcination. The crystalline porous MgAl2O4 spinel, which has complex morphological features, allowed the superior dispersion and stability of Rh clusters, and the core–shell microarchitecture provided facilitated heat and mass transport concomitantly, which enabled a significant enhancement in the glycerol conversion turnover rate to hydrogen compared to the conventional Rh/MgAl2O4 catalyst. This simple and scalable heterogeneous catalyst design approach offers practical applicability for catalytic reactions that require extensive heat and mass flux and rapid process response, such as for micro‐fuel‐processing in fuel cells.

Theory of ESPAR Design With Their Implementation in Large Arrays

A generalized formulation as well as a simple design approach is presented for electronically steerable parasitic array radiators (ESPAR). Based on the presented design procedure, a low-cost rectangular dielectric resonator parasitic phased array antenna is designed. An E-plane linear dielectric resonator phased array coupled to symmetric narrow slot apertures is investigated. The driven element is mutually coupled to the parasitic elements and reactive loads are utilized to control the phase to achieve a particular beam scanning direction. The use of low-cost reactive loads instead of expensive conventional phase shifters allows for more economic fabrication. Based on this design, a five elements planar array is designed and measured. In addition, a large array using ESPAR subarrays is presented.

Micro-electro-mechanically tunable metamaterial with enhanced electro-optic performance

We experimentally demonstrate a micro-electro-mechanically tunable metamaterial with enhanced electro-optical performance by increasing the number of movable cantilevers in the symmetrical split ring resonator metamaterial unit cell. Simulations were carried out to understand the interaction of the incident terahertz radiation with out-of-plane deforming metamaterial resonator. In order to improve the overall device performance, the number of released cantilever in a unit cell was increased from one to two, and it was seen that the tunable range was doubled and the switching contrast improved by a factor of around five at 0.7 THz. This simple design approach can be adopted for a wide range of high performance electro-optical devices such as continuously tunable filters, modulators, and electro-optic switches to enable future photonic circuit applications.

Acoustic and vibration response of a structure with added noise control treatment under various excitations.

The evaluation of the acoustic performance of noise control treatments is of great importance in many engineering applications, e.g., aircraft, automotive, and building acoustics applications. Numerical methods such as finite- and boundary elements allow for the study of complex structures with added noise control treatment. However, these methods are computationally expensive when used for complex structures. At an early stage of the acoustic trim design process, many industries look for simple and easy to use tools that provide sufficient physical insight that can help to formulate design criteria. The paper presents a simple and tractable approach for the acoustic design of noise control treatments. It presents and compares two transfer matrix-based methods to investigate the vibroacoustic behavior of noise control treatments. The first is based on a modal approach, while the second is based on wave-number space decomposition. In addition to the classical rain-on-the-roof and diffuse acoustic field excitations, the paper also addresses turbulent boundary layer and point source (monopole) excitations. Various examples are presented and compared to a finite element calculation to validate the methodology and to confirm its relevance along with its limitations.

Harvesting energy via electromagnetic damper: Application to bridge stay cables

Energy harvesting from ambient vibration is an emerging and promising solution to the power supply problem associated with autonomous sensors. This article proposes a novel strategy of harvesting damping energy from vibration control devices. A novel system, termed electromagnetic damper cum energy harvester, is employed to fulfill both vibration damping and energy harvesting functions. Electromagnetic damper cum energy harvester is essentially an electromagnetic device connected to a specially designed energy harvesting circuit, which is a buck–boost converter operating in a discontinuous conduction mode. The energy harvesting circuit can achieve satisfactory efficiency without any feedback loop. The effectiveness of the dual-function electromagnetic damper cum energy harvester is demonstrated through a numerical case study of bridge stay cables under wind excitations, in which the major parameters of electromagnetic damper cum energy harvester are determined through a simple design approach. Simulation results project average output power ranging from 82.5 to 2396.8 mW at a wind speed of 9–15 m/s, corresponding to an overall efficiency of 42.3%. The dual-function electromagnetic damper cum energy harvester also exhibits vibration control performance comparable to an optimally designed viscous fluid damper.