Search results

The purpose of this paper is to develop a numerical (finite-difference) model exploring phase and group velocities of SH-wave propagation in initially stressed transversely isotropic poroelastic multi-layered composite structures and initially stressed viscoelastic-dry-sandy multi-layered composite structures in two distinct cases.

With the aid of relevant constitutive relations, the non-vanishing equations of motions for the propagation SH-wave in the considered composite structures have been derived. Haskell matrix method and finite-difference scheme are adopted to deduce velocity equation for both the cases. Stability analysis for the adopted finite-difference scheme has been carried out and the expressions for phase as well as group velocity in terms of dispersion-parameter and stability-ratio have been deduced.

Velocity equations are derived for the propagation of SH-wave in both the composite structures. The obtained results are matched with the classical results for the case of double and triple-layered composite structure along with comparative analysis. Stability analysis have been carried out to develop expressions of phase as well as group velocity in terms of dispersion-parameter and stability-ratio. The effect of wavenumber, dispersion parameter along with initial-stress, porosity, sandiness, viscoelasticity, stability ratio, associated with the said composite structures on phase, damped and group velocities of SH-wave has been unveiled.

To the best of authors’ knowledge, numerical modelling and analysis of propagation characteristics of SH-wave in multi-layered initially stressed composite structures composed of transversely isotropic poroelastic materials and viscoelastic-dry-sandy materials remain unattempted inspite of its importance and relevance in many branches of science and engineering.

The recent wave of mergers and acquisitions in the financial institutions all over the developed nations has also taken its toll in Malaysia. Factors such as globalization, liberalization and information technology developments have contributed to the need for a more competitive, resilient and robust financial systems in Malaysia. This is added by the recent 1997 Asian financial crisis, which contributed for speeding the mergers and acquisitions process in the Malaysian banking sector. The end result is the formation of ten anchor banks from a total of 54 financial institutions as at end of 2001. This paper has explored the causes and the process of the mergers and acquisitions as well as the future implications in the Malaysian banking system.

This paper synthesizes existing experimental research in the area of investor perceptions and offers directions for future research. Investor-related experimental research has grown substantially, especially in the last decade, as it has made valuable contributions in establishing causal links, examining underlying process measures, and examining areas with little available data. Within this review, I examine 121 papers and identify three broad categories that affect investor perceptions: information format, investor features, and disclosure credibility. Information format describes how investors are influenced by information salience, information labeling, reporting and accounting complexity, financial statement recognition, explanatory disclosures, and proposed disclosure changes. Investor features describes investors’ use of heuristics, investor preferences, and the effect of investor experience. Disclosure credibility is influenced by external and internal assurance, management credibility, disclosure characteristics, and management incentives. Using this framework, I summarize the existing research and identify areas that would benefit from additional research.

The purpose of this paper is to study the distribution of active earth pressure in retaining walls with narrow cohesion less backfill considering arching effects.

To this end, the approach of principal stresses rotation was used to consider the arching effects.

According to the presented formulation, the active soil pressure distribution is nonlinear with zero value at the wall base. The proposed formulation implies that by increasing the frictional forces at both sides of the backfill, the arching effect is increased and so, the lateral earth pressure on the retaining wall is decreased. Also, by narrowing the backfill space, the lateral earth pressure is extremely decreased.

A comprehensive analytical solution for the active earth pressure of narrow backfills is presented, such that the effects of the surcharge and the characteristics of the stable back surface are considered. The magnitude and height of the application of lateral active force are also derived.

The purpose of this paper is to investigate the effect of corrugation, wave number, initial stress and the heterogeneity of the media on the phase velocity of the Love-type wave. Moreover, the paper aims to have a comparative study of the presence and absence of anisotropy, heterogeneity, corrugation and initial stress in the half-space, which serve as a focal theme of the study.

The present paper modelled the propagation of the Love-type wave in a corrugated heterogeneous monoclinic layer lying over an initially stressed heterogeneous transversely isotropic half-space. The method of separation of variables is used to procure the dispersion relation.

The closed form of dispersion relation is obtained and found to be in well agreement to the classical Love wave equation. Neglecting the corrugation at either of the boundary surfaces, expressions of the phase velocity of the Love-type wave are deduced in closed form as special cases of the problem. It is established through the numerical computation of the obtained relation that the concerned affecting parameters have significant impact on the phase velocity of the Love-type wave. Also, a comparative study shows that the anisotropic case favours more to the phase velocity as comparison to the isotropic case.

Although many attempts have been made to study the effect of corrugated boundaries on reflection and refraction of seismic waves, but the effect of corrugated boundaries on the dispersion of surface wave (which are dispersive in nature) propagating through mediums pertaining various incredible features still needs to be investigated.

The development of mega container ships and operational pressures puts forward higher requirements on the operational ability of the container terminal. Accordingly, the purpose of this paper is to propose an effective method for quay crane (QC) scheduling of multiple hatches vessel considering double-cycling strategy to improve the operation efficiency and reduce the risk of delay.

A mixed integer programming model, which covers the main operational constraints in a container terminal, is formulated to solve the quay crane scheduling problem (QCSP) with a novel objective.

A case study is presented and a number of numerical experiments are conducted to validate the effectiveness of the proposed model. Meanwhile, management insights are proposed. The results demonstrate that the proposed method can efficiently solve QCSP in a container terminal, and an interesting finding is that reducing the stack layers on the vessel can improve the operation efficiency of QC.

A new mathematical model is proposed for QC scheduling at the operational level, which considers the constraints of double-cycling strategy, multiple hatches and hatch covers. The proposed model also provides methods to research the QC double-cycling problem considering the balance between energy cost and operation efficiency.

The analysis of horizontally polarized shear wave (SH-wave) into a piezoelectric layer overlying a functionally graded transversely isotropic (FGTI) half-space under the influence of an impulsive point source existing at its interface is the hallmark of this investigation.

FG in the half-space is caused by quadratic variations in the elastic constants and density. The framework of this study also encompasses the use of Green’s functions technique and Fourier transforms, non-dimensionalization of the resulting equations of motion and grooved boundary conditions occasioned by the modelled problem. The closed-form dispersion equation of SH-wave has been established with the aid of admissible boundary conditions and the properties of Green’s function.

To depict the results numerically, four distinct piezoelectric materials have been considered viz. PZT-5H ceramics, BaTiO₃ ceramics, SiO₂ glass and borosilicate glass. The study manifests the remarkable impact of parameters, viz. piezoelectric constant, dielectric constant and FG parameters through the aid of numerical examples and graphical demonstrations. It is crucial to state that among the four different types of piezoelectric materials, PZT-5H ceramics have the most prominent effect for all the parameters while borosilicate glass has the least.

The originality of this research lies in its novel combination of Green’s function methodology with the study of SH-wave regulation in a specific layered material system, offering insights into both fundamental wave mechanics and potential practical applications. In addition, this study also has potential implications in the fabrication and optimization of surface acoustic wave (SAW) devices, Love wave sensors and transducers.

A direct and unified approach is proposed toward simultaneously simulating large strain elastic behaviors of gellan gels with different gellan polymer concentrations. The purpose of this paper is to construct an elastic potential with certain parameters of direct physical meanings, based on well-designed invariants of Hencky’s logarithmic strain.

For each given value of the concentration, the values of the parameters incorporated may be determined in the sense of achieving accurate agreement with large strain uniaxial extension and compression data. By means of a new interpolating technique, each parameter as a function of the concentration is then obtained from a given set of parameter values for certain concentration values.

Then, the effects of gellan polymer concentrations on large strain elastic behaviors of gellan gels are studied in demonstrating how each parameter relies on the concentration. Plane-strain (simple shear) responses are also presented for gellan gels with different polymer concentrations.

A direct, unified approach was proposed toward achieving a simultaneous simulation of large elastic strain behaviors of gellan gels for different gellan polymer concentrations. Each parameter incorporated in the proposed elastic potential will be derived as a function of the polymer concentration in an explicit form, in the very sense of simultaneously simulating large strain data for different concentrations.

Many studies have shown that rehabilitation robots are crucial for lower limb dysfunction, but application of many robotics have yet to be seen to actual use in China. This study aimed to improve a lower limb rehabilitation robot by details improving and practical design.

Structures and control system of a lower limb rehabilitation robot are improved in detail, including joint calculations, comfort analysis and feedback logic creation, and prototype experiments on healthy individuals and patients are conducted in a hospital.

All participating subjects did not experience any problems. The experiment shows detail improving is reasonable, and feasibility of the robot was confirmed, which has potential for overcoming difficulties and problems in practical application.

Therapeutic effects need to be evaluated in the future. Also, more details should be improved continuously based on the actual demand.

The improved robot could assist the lower limb during standing or walking, which has significance for practical application and patients in China.

The purpose of this paper is to establish mechanisms for process improvement so that production efficiency and product quality can be expected, and create a sustainable development in terms of circular economy.

The authors obtain a critical value from statistical hypothesis testing, and thereby construct a process capability indices chart, which both lowers the chance of quality level misjudgment caused by sampling error and provides reference for the processes improvement in poor quality levels. The authors used the bottom bracket of bicycles as an example to demonstrate the model and methods proposed in this study.

This approach enables us to plot multiple quality characteristics, despite varying attributes and specifications, onto the same process capability analysis chart. And it therefore increases accuracy and precision to reduce rework and scrap rates (reduce), increase product availability, reduce maintenance frequency and increase reuse (reuse), increase the recycle rates of components (recycle) and lengthen service life, which will delay recovery time (recovery).

Parts manufacturers in the industry chain can upload their production data to the cloud platform. The quality control center of the bicycle manufacturer can utilized the production data analysis model to identify critical-to-quality characteristics. The platform also offers reference for improvement and adds the improvement achievements and experience to its knowledge management to provide the entire industry chain. Feedback is also given to the R&D department of the bicycle manufacturer as reference for more robust product designs, more reasonable tolerance designs, and selection criteria for better parts suppliers, thereby forming an intelligent manufacturing loop system.