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1 – 10 of over 3000The purpose of this paper is to empirically examine the effect on US stock, bond and real estate investment trust (REIT) prices triggered by the US Federal Reserve Chairman Ben…
Abstract
Purpose
The purpose of this paper is to empirically examine the effect on US stock, bond and real estate investment trust (REIT) prices triggered by the US Federal Reserve Chairman Ben Bernanke’s announcement of a possible intent to unwind, or taper, quantitative easing (QE). In particular, the author assessed whether the effect of the “Taper Tantrum” was fundamental or financial on financial markets.
Design/methodology/approach
The methodology used to determine whether the effect of the “Taper Tantrum” was fundamental or purely financial is that suggested by French and Roll (1986) as extended by Tuluca et al. (2003). The analysis is based on daily data for large cap stocks, small cap stocks, long-term bonds and REITs for 18 months before Ben Bernanke’s announcement and for 18 months after the announcement.
Findings
The results show that the “Taper Tantrum” had a fundamental, rather than a financial effect on all asset classes, especially so for REITs.
Practical implications
The author also found that in the post-taper period following Ben Bernanke’s announcement the correlation of REITs with stocks decreased compared with pre-taper period, whereas the correlation of REITS with bonds increased substantially. In other words, the “Taper Tantrum” had a profound effect on the risk/return benefits of including REITs in the US mixed-asset portfolio.
Originality/value
This is the first paper to examine the effect of the “Taper Tantrum” on REITs.
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Fatimah De’nan, Nor Salwani Hashim and Mohd Yusri Mohamad Razak
Tapered steel sections are widely used in house building design due to their structural efficiency and aesthetic appearance. Due to the practical usage of web tapering…
Abstract
Purpose
Tapered steel sections are widely used in house building design due to their structural efficiency and aesthetic appearance. Due to the practical usage of web tapering specifications in the metal building industry, fabrication and material expenses are analyzed to achieve geometric and economic productivity. The purpose of this study is to investigate the effectiveness of utilizing web profiles with openings in reducing the weight of steel beams.
Design/methodology/approach
In this paper, the nonlinear analysis of the bending behavior of a tapered steel section with an opening was studied by finite element analysis. The results were then compared with those of the tapered steel section without an opening in terms of displacement and yield moment.
Findings
The bending capacity of a tapered steel section was analyzed using finite element analysis. Results showed that the tapered steel section without openings had a higher bending capacity compared to the section with various sizes of web openings. The results also showed that decreasing the number of openings would increase the bending capacity, whereas increasing the size of the opening would decrease it. The difference in the yield moment between the tapered steel section with and without openings was only 15.818%. A total of 60 nonlinear analyses were conducted to investigate the effect of the number and size of web openings, flange thickness and web thickness on the bending behavior. However, this study showed that web opening with octagon shape and 0.6D size of web opening, where D is the depth of section, showed the best section in terms of yield moment and volume reduction compared to other opening size and shape.
Originality/value
It is also found that tapered steel section has better moment resistance in thicker flange and web. The study is valuable for engineers and designers who work with steel structures and need to optimize the performance of tapered steel sections with web openings.
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Fatimah De’nan, Nor Salwani Hashim and Ngo Siew Ting
Recently, this steel section has found increasing popularity in residential, industrial and commercial buildings with their high load-carrying capacity due to the nature of high…
Abstract
Purpose
Recently, this steel section has found increasing popularity in residential, industrial and commercial buildings with their high load-carrying capacity due to the nature of high strength to weight ratio properties. However, the rise on the price of steel section should be more emphasized; therefore, the optimization in steel section design is needed to overcome the issue of material cost. As such, tapered steel sections save on material use, while the introduction of web openings allows the placement of mechanical and electrical services, plumbing and also aesthetic design considerations.
Design/methodology/approach
The purpose of this study is to investigate the lateral torsional buckling behavior of a tapered steel section with an ellipse-shaped opening by analyzing its structural parameters. To achieve this, the finite element analysis (FEA) of the section is modeled using LUSAS software, which allows for a detailed analysis of the section's behavior under varying loads and conditions. It involves the variation in web opening size, opening layout, opening rotation angle and the tapering ratio. Eigenvalue buckling analysis is adopted to know the parametric effects of each 108 model. The size of opening varies from 0.2 to 0.5 d of the total depth where the opening located. There are three type of layouts applied in this study, which are the layouts A, B and C. There are three types of rotation angles for the ellipse-shaped opening, including the non-rotated vertical opening and two additional types formed by rotating the opening 45 degrees clockwise and counterclockwise around the center-point of the ellipse. A fixed-free boundary condition was applied, resulting in a simulation of a cantilever beam. The models are fixed at one end with a larger depth, and free at the other end with a smaller depth. Loading condition is an application of 10 kN/m uniform distributed load in the direction of gravity along the mid-span of the top flange.
Findings
It is observed that the model 82 with Layout A, tapering ratio 0.3, opening size 0.5 d and opening rotated in 45 degree anti-clockwise direction results in the highest structural efficiency among the 108 models. Therefore, the buckling moment of model 82 is 1,013.08 kNm with structural efficiency of 481.26, which shows an increase of 3.17% compared to the controlled model.
Originality/value
The FEA results shows a significant increase in ductility and stiffness of the tapered steel section with elipse shape opening and consequently changes in the behaviour of yield point.
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Lourelay Moreira dos Santos, Guilherme Ferreira Gomes and Rogerio F. Coimbra
The purpose of this study is to investigate the aerodynamic characteristics of a low-to-moderate-aspect-ratio, tapered, untwisted, unswept wing, equipped of sheared wing tips.
Abstract
Purpose
The purpose of this study is to investigate the aerodynamic characteristics of a low-to-moderate-aspect-ratio, tapered, untwisted, unswept wing, equipped of sheared wing tips.
Design/methodology/approach
In this work, wind tunnel tests were made to study the influence in aerodynamic characteristics over a typical low-to-moderate-aspect-ratio wing of a general aviation aircraft, equipped with sheared – swept and tapered planar – wing tips. An experimental parametric study of different wing tips was tested. Variations in its leading and trailing edge sweep angle as well as variations in wing tip taper ratio were considered. Sheared wing tips modify the flow pattern in the outboard region of the wing producing a vortex flow at the wing tip leading edge, enhancing lift at high angles of attack.
Findings
The induced drag is responsible for nearly 50% of aircraft total drag and can be reduced through modifications to the wing tip. Some wing tip models present complex geometries and many of them present benefits in particular flight conditions. Results have demonstrated that sweeping the wing tip leading edge between 60 and 65 degrees offers an increment in wing aerodynamic efficiency, especially at high lift conditions. However, results have demonstrated that moderate wing tip taper ratio (0.50) has better aerodynamic benefits than highly tapered wing tips (from 0.25 to 0.15), even with little less wing tip leading edge sweep angle (from 57 to 62 degrees). The moderate wing tip taper ratio (0.50) offers more wing area and wing span than the wings with highly tapered wing tips, for the same aspect ratio wing.
Originality/value
Although many studies have been reported on the aerodynamics of wing tips, most of them presented complex non-planar geometries and were developed for cruise flight in high subsonic regime (low lift coefficient). In this work, an exploration and parametric study through wind tunnel tests were made, to evaluate the influence in aerodynamic characteristics of a low-to-moderate-aspect-ratio, tapered, untwisted, unswept wing, equipped of sheared wing tips (wing tips highly swept and tapered).
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Lucian Capitanu, Liliana-Laura Badita, Constantin Tiganesteanu and Virgil Florescu
The purpose of this paper is to study the roughness effect on the fixation of taper junction components and surfaces wear in terms of taper surface design. The roughness of the…
Abstract
Purpose
The purpose of this paper is to study the roughness effect on the fixation of taper junction components and surfaces wear in terms of taper surface design. The roughness of the femoral heads’ taper and of the femoral stems’ trunnions can influence the fretting wear of the taper junction.
Design/methodology/approach
It was analysed whether a microgrooved taper surface of the femoral stem trunnion improves the fixation and reduces the wear rate at the taper junction of the hip prosthesis. Two models have studied: a femoral head with a smooth tapered surface combined with a microgrooved stem trunnion and a femoral head with a smooth tapered surface combined with a trunnion that had a smooth surface of the tapered. To compare the wear evolution between these two models, a computerised finite element model of the wear was used.
Findings
The results obtained after analysis carried out during millions of loading cycles showed that the depth of the linear wear and the total material loss were higher for the femoral heads joined with microgrooved trunnions. The main conclusion of this paper is that the smooth surfaces of the taper and of the trunnions will ensure a better fixation at the taper junction, and therefore, will reduce the volumetric wear rates.
Originality/value
A higher fixation of the taper junction will reduce the total hip prosthesis failure and, finally, it will improve the quality and durability of modular hip prostheses.
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Fatimah De'nan, Nor Salwani Hashim and Xing Yong Sua
With the vast advancement of structural steel properties over the recent decades, structural steel has become the dominate material for the construction of bridges, stadiums…
Abstract
Purpose
With the vast advancement of structural steel properties over the recent decades, structural steel has become the dominate material for the construction of bridges, stadiums, factories and high rise buildings. This paper aims to present the study of structural behaviour and efficiency of tapered steel section with elliptical perforation under shear loading conditions.
Design/methodology/approach
The effect of various elliptical perforation configurations such as tapering ratio, perforation size, perforation orientation and perforation layout on the shear behaviour of tapered steel section has been investigated by using finite element method. A total of 112 models are simulated via LUSAS software.
Findings
It has been found that the most efficient model is the tapered steel section with tapering ratio of 0.3 and vertical elliptical perforation of 0.2 times the section depths which are arranged in Layout 3. The most efficient model has a shear efficiency of 1,094.35 kN, which is 4.12% less than the tapered steel section without perforation, but it could achieve a 0.32% of weight reduction.
Originality/value
The smaller tapering ratio and perforation size contributed to the higher shear buckling capacity and efficiency for the elliptical perforated tapered steel section.
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Muhamad Ramdzan Buyong, Farhad Larki, Muhamad Ikhmal Hakimi Zainal, Abdelaziz Yousif Ahmed Almahi, Ahmad Ghadafi Ismail, Azrul Azlan Hamzah, Aminuddin Ahmad Kayani Kayani, Céline Elie Caille and Burhanuddin Yeop Majlis
This paper aims to present the capacitance characterization of tapered dielectrophoresis (DEP) microelectrodes as micro-electro-mechanical system sensor and actuator device. The…
Abstract
Purpose
This paper aims to present the capacitance characterization of tapered dielectrophoresis (DEP) microelectrodes as micro-electro-mechanical system sensor and actuator device. The application of DEP-on-a-chip (DOC) can be used to evaluate and correlate the capacitive sensing measurement at an actual position and end station of liquid suspended targeted particles by DEP force actuator manipulation.
Design/methodology/approach
The capability of both, sensing and manipulation was analysed based on capacitance changes corresponding to the particle positioning and stationing of the targeted particles at regions of interest. The mechanisms of DEP sensor and actuator, designed in DOC applications were energized by electric field of tapered DEP microelectrodes. The actual DEP forces behaviour has been also studied via quantitative analysis of capacitance measurement value and its correlation with qualitative analysis of positioning and stationing of targeted particles.
Findings
The significance of the present work is the ability of using tapered DEP microelectrodes in a closed mode system to simultaneously sense and vary the magnitude of manipulation.
Originality/value
The integration of DOC platform for contactless electrical-driven with selective detection and rapid manipulation can provide better efficiency in in situ selective biosensors or bio-detection and rapid bio-manipulation for DOC diagnostic and prognostic devices.
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The purpose of this paper presents the effects of actively morphing root chord and taper on the energy of the flight control system (i.e. FCS).
Abstract
Purpose
The purpose of this paper presents the effects of actively morphing root chord and taper on the energy of the flight control system (i.e. FCS).
Design/methodology/approach
Via regarding previously mentioned purposes, sophisticated and realistic helicopter models are benefitted to examine the energy of the FCS.
Findings
Helicopters having actively morphing blade root chord length and blade taper consume less control energy than the ones having one of or any of passively morphing blade root chord length and blade taper.
Practical implications
Actively morphing blade root chord length and blade taper can be used for cheaper helicopter operations.
Originality/value
The main originality of this paper is applying active morphing strategy on helicopter blade root chord and blade taper. In this paper, it is also found that using active morphing strategy on helicopter blade root chord and blade taper reasons less energy consumption than using either passively morphing blade root chord length plus blade taper or not any. This causes also less fuel consumption and green environment.
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Fatimah De'nan, Nor Salwani Hashim and Lim Cheng Kuan
Tapered section can resist maximum stress at a single location while the stresses are considerably lower at the rest of the member; therefore, it could have higher structural…
Abstract
Purpose
Tapered section can resist maximum stress at a single location while the stresses are considerably lower at the rest of the member; therefore, it could have higher structural efficiency compared to conventional section. It could also satisfy functional requirements while reducing weight and cost in many fields of civil construction. Perforation in the steel section also eases the integration of Mechanical and Electrical (M&E) services such as ventilation pipes and electrical cables within the structural depths of the beam. In this analysis, the structural efficiency of tapered steel section with perforation under lateral-torsional buckling behaviour is investigated.
Design/methodology/approach
A total of 81 models are analysed using LUSAS software and five variables are investigated which involved perforation sizes, perforation shapes, perforation layout, tapering ratio and flange and Web thickness. Buckling moment is obtained from the analysis results in LUSAS software, while self-weight and structural efficiency are manually calculated.
Findings
Perforation size of 0.75 D has the highest structural efficiency, although it can withstand a smaller buckling load. This is due to its lower self-weight compared to other perforation sizes. The square perforation shape also has the highest structural efficiency compared to circular perforation and diamond perforation. An increment of percentage in structural efficiency of the square perforation shape with 0.75 D is the highest at 3.07%. The circular perforation shape with 0.75 D (Open-Open-Open perforation layout) has the highest increment of percentage in structural efficiency which is 2.37%. The tapering ratio of 0.3 is the most efficient and an increment of percentage in structural efficiency is 114.36%. The flange thickness of 0.02 m and Web thickness of 0.015 m has the highest structural efficiency at 45.756 and 29.171, respectively.
Originality/value
In conclusion, a section should be able to resist the large buckling moment and has a lower self-weight to achieve high structural efficiency.
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Zi Guo, Fenghong Chu, Jinyu Fan, Ze Zhang, Zhenglan Bian, Gaofang Li and Xiaojun Song
The purpose of this paper is to propose and optimize plastic optical fiber (POF) probe with macro-bending biconical tapered structure for the relative humidity (RH) sensing.
Abstract
Purpose
The purpose of this paper is to propose and optimize plastic optical fiber (POF) probe with macro-bending biconical tapered structure for the relative humidity (RH) sensing.
Design/methodology/approach
In this study, the principle is the evanescent wave power modulated by the ambient humidity. The probe is fabricated by using fused biconical taper and heat-setting method and then coated with a fluorescent moisture-sensitive film.
Findings
The probe’s sensing performance can be optimized by changing the probe’s curvature radius, biconical tapered transition length and taper waist diameter. The result shows that the sensitivity of the probe is up to 1.60 and 3.40 mV/ per cent, respectively, at low humidity (10-45 per cent) and high humidity (45-90 per cent). Also, this probe has good linearity, repeatability, photostability and long-term stability.
Practical implications
The proposed probe can improve the sensitivity and linearity of RH sensing without complex devices, which is necessary for mass production, remote measurement and convenient operation.
Originality/value
POF probe with macro-bending biconical tapered structure is investigated in this paper, which is proved to be effective in improving the sensitivity and linearity.
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