Search results

The purpose of this study is to present a highly stretchable and flexible strain sensor with simple and low cost of fabrication process and excellent dynamic characteristics, which make it suitable for human motion monitoring under large strain and high frequency.

The strain sensor was fabricated using the rubber/latex polymer as elastic carrier and single-walled carbon nanotubes (SWCNTs)/carbon black (CB) as a synergistic conductive network. The rubber/latex polymer was pre-treated in naphtha and then soaked in SWCNTs/CB/silicon rubber composite solution. The strain sensing and other performance of the sensor were measured and human motion tracking applications were tried.

These strain sensors based on aforementioned materials display high stretchability (500 per cent), excellent flexibility, fast response (approximately 45 ms), low creep (3.1 per cent at 100 per cent strain), temperature and humidity independence, superior stability and reproducibility during approximately 5,000 stretch/release cycles. Furthermore, the authors used these composites as human motion sensors, effectively monitoring joint motion, indicating that the stretchable strain sensor based on the rubber/latex polymer and the synergetic effects of mixed SWCNTs and CB could have promising applications in flexible and wearable devices for human motion tracking.

This paper presents a low-cost and a new type of strain sensor with excellent performance that can open up new fields of applications in flexible, stretchable and wearable electronics, especially in human motion tracking applications where very large strain should be accommodated by the strain sensor.

The purpose of this paper is to provide strong theoretical and technical support for the dynamic evolution of service system in “Cluster Supply Chain”(CSC), which can deal with two kinds of context changes: the internal service component changes and the external customer requirement changes.

A “feedback-based” evolution mechanism of service system for CSC is proposed in this study. By means of the feedback update of enterprise service’s Quality of Service (QoS) attribute and the adjustment of the assumed QoS evaluation model, the evolution of service system can be achieved to suit the dynamic market demands.

Results of the study suggest: by means of the “feed-back” evolution mechanism of service system, the enterprises in CSC can handle the context changes effectively to maintain the optimized operation status.

The implementation of evolution mechanism in service system can keep the effectiveness of enterprise service composition to face the frequent service component changes and the unpredictable market turbulence.

This paper proposes a method to realize the autonomous evolution of service system in CSC, which can support the flexibility and adaptability of enterprise service composition in the changing environment.

Continuous understanding of the best practices associated with new product development is a constant research opportunity to advance knowledge in the field, as far as changes in the business environment and the increasing turbulence level in different market segments create and reposition the importance of practices over time.

Based on a systematic review, the study aimed to analyze the 100 most relevant articles published in international journals on new product development (NDP), identifying new patterns on the best practices for new product development and the types of relationship involved in NPD.

Among the several practices observed in the literature, the analysis point to a larger group of studies that converge on the identification of a positive and significant relationship in integration – simultaneously – between supplier, company, customers and strategic alliances and the performance of NPD.

These results support integration as a cross-cutting and structural best practice for NPD, as long as it is constituted as a capacity, mainly applied in highly turbulent environments. This approach supported the proposition of a new framework.

Organizations will be able to implement the proposed framework to NPD strategy in order to prioritize resources in best practices, aiming to increase the performance of new product development.

The adoption of integration and co-creation practices for the development of new products expands the possibilities of economic and social development, based on the involvement of the actors in this network.

This model had not yet been proposed in the literature, filling a gap in the agenda for future studies.

The purpose of this paper is to propose and demonstrate a new additive manufacturing approach that breaks the layer-based point scanning limitations to increase fabrication speed, obtain better surface finish, achieve material flexibility and reduce equipment costs.

The freeform additive manufacturing approach conceptually views a 3D article as an assembly of freeform elements distributed spatially following a flexible 3D assembly structure, which conforms to the surface of the article and physically builds the article by sequentially forming the freeform elements by a vari-directional vari-dimensional capable material deposition mechanism. Vari-directional building along tangential directions of part surface gives surface smoothness. Vari-dimensional deposition maximizes material output to increase build rate wherever allowed and minimizes deposition sizes for resolution whenever needed.

Process steps based on geometric and data processing considerations were described. Dispensing and forming of basic vari-directional and vari-dimensional freeform elements and basic operations of joining them were developed using thermoplastics. Forming of 3D articles at build rates of 2-5 times the fused deposition modeling (FDM) rate was demonstrated and improvement over ten times was shown to be feasible. FDM compatible operations using 0.7 mm wire depositions from a variable exit-dispensing unit were demonstrated. Preliminary tests of a surface finishing process showed a result of 0.8-1.9 um Ra. Initial results of dispensing wax, tin alloy and steel were also shown.

This is the first time that both vari-directional and vari-dimensional material depositions are combined in a new freeform building method, which has potential impact on the FDM and other additive manufacturing methods.

The paper aims to study how global pharmaceutical companies such as Pfizer have managed the challenges of pharmaceutical patent expiry.

A case study method was applied. The best-selling brand drug over the past 10 years – Lipitor – was chosen as the case target.

For dealing with this, this paper describes all the details of the corresponding strategies of Pfizer before and after patent expiration of Lipitor. Before patent expiry, Pfizer undertook the activities of direct-to-consumer marketing, pricing strategy for competition, legal delay and me-too drug R&D. After patent expiry, Pfizer chose to carry out continuous marketing for brand, rebate strategy, authorized generics and change to over-the-counter. In addition, diversity and globalization strategy was applied before and after patent expiry.

This research provides strong implication for managing pharmaceutical products before and after patent expiry.

It is strongly recommended for both brand and generic drug companies to design strategies to meet the challenges of pharmaceutical patent expiry.

For the global pharmaceutical market, a conclusion can be drawn that, nowadays, the “patent cliff” is the most significant factor influencing decision-makers to consider futuristic policies. Further, it is also a considerably effective solution for reducing health-care costs for policymakers.

This paper contributes to the field of patent expiry management in high-tech industries such as pharmaceuticals.

Corrosion inhibitors for copper immersed in emulsion were investigated by experiments and theoretical calculations, and this study aims to propose a new inhibition mechanism of the inhibitors having protective effects for copper corrosion.

Adsorption behavior of penta-heterocycles (thiophene, 1,2,5-oxadiazole, furan, 2 H-1,2,3-triazole, pyrrole and 1,2,5-thiadiazole) as corrosion inhibitors for copper immersed in oil-in-water (O/W) emulsions was investigated by weight loss, electrochemical tests, morphological characterization and theoretical calculations.

The orders of inhibition effect are furan < pyrrole < thiophene < 1,2,5-oxadiazole < 2H-1,2,3-triazole < 1,2,5-thiadiazole, and 1,2,5-thiadiazole at 0.5 mM has the best inhibition effect for copper immersed in emulsion. The results of scanning probe microscope, scanning electron microscope and electrochemical test show that a protective barrier can be formed on the surface of copper substrate with six corrosion inhibitors, thus effectively inhibiting the corrosion of copper mainly through chemisorption and following Langmuir’s adsorption isotherm.

Quantum chemical and molecular dynamic simulations demonstrate that all these compounds attached to Cu matrix with a flat-adsorption mode to prevent the emulsion corrode copper. Adsorbed inhibitors act as a barrier at Cu matrix to block corrosion and improve hydrophobicity.

The purpose of this paper is to investigate the dynamic characteristics of a spiral groove liquid film seal considering the effect of cavitation.

A mathematical model of a spiral groove liquid film seal was established based on the mass-conserving Jakobsson–Floberg–Olsson cavitation boundary condition. The film rupture and film reformation boundaries were assumed to be unchanged under infinitesimal perturbation conditions. Governing equations under steady and perturbed states were solved by the finite element method, and then the dynamic characteristics of the spiral groove liquid film seal were theoretically investigated considering the effect of cavitation.

The results indicate that dynamic coefficients considering cavitation are smaller than those neglecting cavitation. The difference value is consistent with the change in cavitation area. The liquid film seal does not suffer axial instability whether considering cavitation, but its angular instability is more likely to occur when cavitation is considered.

For liquid lubricated non-contacting mechanical seals, the dynamic characteristics considering cavitation are investigated. The results are expected to provide a theoretical basis for improving the design method of liquid film seals.

To authenticate the existence and principles of the adhesion recovery phenomenon under water pollution conditions, an innovative circumferential rail–wheel adhesion test rig was used. The study conducted extensive tests on the adhesion characteristics under large sliding conditions.

Experiments were conducted to investigate the influence of speed, axle load and slip on adhesion recovery. Based on the experimental results, the adhesion recovery transition function was re-fitted.

The study reveals that the adhesion recovery phenomenon truly exists under water conditions. The adhesion coefficient shows an increasing trend with the growth of the slip ratio. Moreover, at the current speed and axle load levels, the adhesion recovery is directly proportional to the square of the slip ratio and inversely proportional to the axle load.

The phenomenon of adhesion recovery and the formulated equations in this study can serve as an experimental and theoretical foundation for the design of braking and anti-skid control algorithms for trains.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2023-0379/

This work aims to demonstrate the vibration suppression of the rotor system with localized defects on bearing using an integral squeeze film damper (ISFD).

Experiments were carried out to study the vibration characteristics of the rotor system with ISFD mounted on fault deep groove ball bearings. Three fault bearings including bearing with outer race defect, inner race defect and ball defect have been used in this paper. The results were compared by use of vibration acceleration level, continuous wavelet transform and envelope spectrum.

It was found that ISFD shows excellent damping and vibration attenuation characteristics of the rotor system with defective bearing. The fault bearing rotor system with external ISFD considerably reduces the vibration energy and amplitude compared with the system without ISFD.

There is a dearth of experimental research pertaining to vibration characteristics of rotor system support by defective bearings with ISFD. Besides, the test provides evidence for the application of ISFD in vibration control of the rotor system with incipient defects on bearing.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0144/

This study aims to using Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and scanning electron microscope/energy dispersive Xray spectrometer to identify different automotive coatings for forensic purpose.

Two four-layered samples in a hit-and-run case were compared layer by layer with three different methods. FTIR spectroscopy was used to primarily identify the organic and inorganic compositions. Raman spectrum and scanning electron microscope/energy dispersive Xray spectrometer (SEM-EDS) were further used to complement the FTIR results.

Two weak and tiny peaks in one layer found between two samples by FTIR, Raman microscope and SEM-EDS verified the result of differences. The study used the three instruments in combination and found it’s effective in sensing coatings, especially in the inorganic additives.

Using these three instruments in combination is more accurate than individually in multilayered coating analysis for forensic purpose.

The three different instruments all present unique information on the composition, and provided similar and mutually verifiable results on the two samples.

With this method, scientists could identify and discriminate important coating evidences with tiny but characteristic differences.