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The purpose of this paper is to give a brief introduction of helical spring locked washer along with extensive literatures survey on role of helical spring locked washer in bolted joint analysis. It is very small component of bolted joint assembly, but it play vital role in holding the assembly components together. Helical shape of it produces spring effect in the assembly which is used for keeping the assembly in tension and that is lock the assembly under dynamic loading due to vibrations to avoid the accident.

The critical literatures survey identifies role of helical spring locked washer in different areas such as design optimization, mechanism of loosening-resistant components, bolted joint analysis, finite element-based modeling, analysis and simulation. The related literatures show contribution of helical spring washers in evaluation of anti-loosening performance of assemblies as compare to other types of washers.

It proposed that design optimization of helical spring locked washer is needed as it improves the performance in the form of load-deflection characteristics, load bearing capacity and provides the best locking force for optimize functionality.

The originality or value of this paper is to finding research gaps in literatures by dividing literatures into seven different research areas and concentrating the only on role of helical spring locked washer in bolted joint analysis.

Recycling technology for printed wiring boards (PWBs) with mounted electronic components was studied for the purpose of disassembling the boards, recovering useful materials, and reusing these materials. An automatic removal method was developed for the electronic components on the basis of a combination of heating to above the solder melting temperature and applying impacting the shearing forces. Most of the electronic components were recovered undamaged and the solder was able to be recovered as particles. The solder remaining on the board was recovered by abrading the board surface and by using a heating‐impacting process. After these processes, the resin board (a cured epoxy resin board reinforced with glass fibre)was pulverised and separated into a copper‐rich powder (copper: 82 Wt%) and a glass fibre and resin mixture powder (glass fibre‐resin powder) by gravimetric and electrostatic methods. The recovered electronic components, solder and copper‐rich powder were used as valuable metal resources for refining. Moreover, the recovered glass fibre‐resin powder was found to be a useful filler for plastic products such as epoxy resin and ABS (acrylonitrile/butadiene/styrene copolymer) resin.

This paper seeks to set out opportunities for the development of a UK‐focused feasibility and sizing model utilising linear programming.

Optimisation of the model is conducted using integer linear programming developed using Excel Solver.

When compared with comparable alternatives, the model is shown to be particularly useful as its functionality is embedded in resource intensive prime mover specifications obtained from seven real industrial cases.

The study acknowledges the limitation of utilising sizing data primarily obtained from secondary sources to develop the model.

The practical usefulness of this model is that it has been built using “real”, as opposed to simulated‐data. When compared with comparable alternatives, the model is shown to be articularly useful as its functionality is embedded in resource intensive prime mover specifications obtained from seven real industrial cases.

A boom in e-commerce in Korea has sparked off high daily-volume demand for small-sized home delivery services, which poses a great challenge to distribution networks, especially in urban areas where traffic congestion, accessibility, and pollution are serious problems. In addition, security issues for people who live in small townhouses and detached houses without security systems and guards have received increasing attention from the government and society. Thus, the introduction of a new alternative for home delivery services, unmanned parcel lockers, is urgent for residents living in these areas. This paper examines and compares potential socio-economic impacts in terms of costs and benefits when such lockers are installed at selected locations in residential areas. The results show that this policy is worthy of adoption, with several undeniable benefits to local communities. In addition, sensitivity analyses estimate the economic performance of this project at different social discount rates, and they check the sensitivity of economic performance based on variations in the variables. The value of travel time savings was identified as a critical and dominating factor directly affecting economic performance.

A semantic analysis of the “Weekly Subject Index Stop Word List” of Current Contents of the Institute for Scientific Information (ISI) as well as of the full‐stop word and semi‐stop word lists of the Permuterm Subject Index of Science Citation Index was carried out. Selected terms from the first issues for 1997, 1999 and 2000 of the CCODAb/Life Sciences, of the first issues for 1997 and 2000 of CCOD Proceedings, as well as from the SCI CDE for 1997 and January‐June of 2000 were screened. True full‐stop and semi‐stop words commonly occur in the dictionaries of these databases which proves that there is an abundance of meaningless terms in titles and abstracts. On the other hand, many synonyms and antonyms are absent in these lists. Proper list enlarging could contribute to more effective preparation of both printed reference publications and large databases thus ensuring a more economic information retrieval by practical users and scientometricians. The necessity of an improved, semantically oriented policy in preparing the lists of fullstop words and semi‐stop words used in modern databases worldwide is emphasised. Journal editors should encourage authors to reduce stop‐word usage in article titles and keyword sets.

The purpose of this paper is to present an investigation of the effect of different gravity conditions on the penetration mechanism using the two-dimensional Distinct Element Method (DEM), which ranges from high gravity used in centrifuge model tests to low gravity incurred by serial parabolic flight, with the aim of efficiently analyzing cone penetration tests on the lunar surface.

Seven penetration tests were numerically simulated on loose granular ground under different gravity conditions, i.e. one-sixth, one-half, one, five, ten, 15 and 20 terrestrial gravities. The effect of gravity on the mechanisms is examined with aspect to the tip resistance, deformation pattern, displacement paths, stress fields, stress paths, strain and rotation paths, and velocity fields during the penetration process.

First, under both low and high gravities, the penetration leads to high gradients of the value and direction of stresses in addition to high gradients in the velocity field near the penetrometer. In addition, the soil near the penetrometer undergoes large rotations of the principal stresses. Second, high gravity leads to a larger rotation of principal stresses and more downward particle motions than low gravity. Third, the tip resistance increases with penetration depth and gravity. Both the maximum (steady) normalized cone tip resistance and the maximum normalized mean (deviatoric) stress can be uniquely expressed by a linear equation in terms of the reciprocal of gravity.

This study investigates the effect of different gravity conditions on penetration mechanisms by using DEM.

The aim of this paper was to investigate the effect of strain rate on microstructure and corrosion behavior of 2205 duplex stainless steel, after high-temperature compression tests.

The specimens were prepared using a Gleeble3800 thermo-simulation machine over a range of temperatures from 850 to 1,250°C and strain rates from 0.005 to 5 s−1, and the corresponding flow curves and deformation microstructure obtained were further analyzed. To evaluate the effect of strain rate on corrosion behavior, potentiodynamic polarization tests and double-loop electrochemical potentiodynamic reactivation (DL-EPR) were used to characterize the electrochemical performance.

Compared with strain rate of 0.5 s−1, the worst corrosion resistance behavior from the potentiodynamic polarization test results after deformation at 0.005 s−1 was attributed to more austenite (γ) and ferrite (δ) grain boundaries or δ/γ phase interface formation due to the better effect of γ dynamic recrystallization (DRX) or δ dynamic recovery (DRV). Increasing strain rate to 5 s−1 lowered the corrosion resistance, due to the increase in dislocation density. At the low strain rate of 0.005 s−1, the susceptibility to intergranular corrosion (IGC) was comparatively high after deformation at 1050 and 1150°C with more γ/γ grains and δ/γ phase boundary formation, which was lowered with the strain rate increase to 0.5 s−1, due to suppressing effect of γ DRX.

The paper provides the scientific basis for the practical application of hot working of 2205 duplex stainless steel.

This paper aims to develop ring resonator type optical sensors for high-sensitive detection of biomaterials and a solution concentration surrounding sensor devices. The sensing characteristics of a proposed device are investigated.

The proposed device structure is multi-slot ring resonator where the horizontal slots are arranged in vertical direction called as stacked multi-slot ring resonator. The ring resonator consists of silicon nitride because of several advantages such as easy integration of Si photo-detectors. A high sensitivity is expected in this structure because the slot height is precisely controlled by the thickness of stacked silicon nitride and etched silicon oxide layers. Sensing characteristics are evaluated from the simulated effective refractive index using the finite element method and sucrose solution sensing is confirmed using polydimethylsiloxane fluid channel.

In the simulation for the solution concentration sensor, the detection sensitivity is enhanced with increasing the slot height and the number of slots. On the other hand, for the biomaterial sensor such as the adsorbed antigen-antibody reaction, the sensitivity increases with decreasing the slot height. In this case, more than four times higher sensitivity is expected compared with the slot ring resonator sensor with vertical single slot and 0.1-0.2 μm slot width.

This paper presents an improved new structure of ring resonator type sensors and its optimum design parameters. The sensing characteristics are evaluated, and, for the biomaterial sensor, the sensitivity is high in comparison to the previous slot ring resonator.

The purpose of this paper is to present an update and the latest results from work on a project aimed at enabling waste printed circuit board (WPCB) recycling to become more environmentally friendly and efficient.

A new system was proposed and studied individually under laboratory and factory conditions, which consisted of lossless component removal, component classification, waste crushing/separating processes, and application of crushed non‐metallic particles to develop resin composites.

The use of these novel processes, including component lossless removal, component classification, waste crushing/separating processes, and application of crushed non‐metallic particles to develop resin composites can be combined to give a more sustainable treatment process for printed circuit boards recycling.

Most parts of the WPCBs recycling system have been used. Further development work should be undertaken to establish the whole system in a factory‐scale environment in order to enhance the system efficiency.

The paper details how individual treatment technologies can be combined to enable a more environmentally friendly and efficient system for treatment of WPCBs which offers the benefits of reducing pollution and complete resource recovery for WPCBs.

The purpose of this study is to explore the role individual innovativeness along with e-learning self-efficacy play in predicting the e-learning readiness of first- and second-year students of an open and distance education institutions in an African context.

Therefore, building on previous related research in this area, a quantitative approach was adopted to address the research questions and to establish whether a statistically significant relationship existed between individual innovativeness, e-learning self-efficacy, the independent variables; and e-learning readiness, the dependent variable. In total, 476 first- and second-years students of the university participated in the four-Likert-type scale survey. The research instrument which comprises 74 survey items was completed by 217 of the students. Statistical tools used for analysing data included both Pearson Product Moment Correlation coefficients and t-tests.

It was discovered that a strong positive and significant relationship was observed between individual innovativeness and e-learning readiness of first- and second-year students of the Yenagoa Study Centre of the National Open University of Nigeria (NOUN); a statistically significant relationship was also found between e-learning self-efficacy scores and the e-learning readiness of the first- and second-year students of the Yenagoa Study Centre of NOUN; there was a statistically significant joint relationship between the three variables under investigation; findings equally revealed that male respondents had higher e-learning readiness than their female counterparts.

Like every other study of this nature, this one also suffers some limitations. First, NOUN is a very large university with over half a million students spread across almost 78 study centres. This means that observation from just one study centre amounts to a very small sample size. This according to Schweighofer, Weitlaner, Ebner and Rothe (2019) jeopardises the generalisability and validity of study results. The authors also maintain that empirical data generated from surveys that usually rely participants' abilities to read and select responses without further interpretation by the researchers suffer from cognitive biases like social desirability. To address the above limitations, detailed studies involving all studies centres of NOUN be undertaken and other qualitative and or mixed research methodologies be adopted in the future.

The implications for this study are that people who are innately innovative will willingly accept technology and by extension, learning in technology-rich environments like those found in like NOUN whose mode of study is blended learning inherently found in open and distance learning (ODL) institution. Therefore, this study is significant as it will provide relevant information to the management and administrators of NOUN, policymakers and regulatory institutions for the development, deployment and implementation of e-learning strategies. Findings will also benefit e-learning initiatives undertaken by similar institutions that adopt the ODL mode of education in Nigeria and other developing countries.

Even though, studies on the antecedents of e-learning readiness have been widely conducted across diverse contexts, studies exploring the associations between individual innovativeness, e-learning self-efficacy and e-learning readiness are relatively hard to come by. The above two variables as predicting the e-learning readiness in the study context are comparatively new. This study thus focuses on the relationships between the individual innovativeness levels, e-learning self-efficacy beliefs of students and their e-learning readiness which ultimately determines their ability to sustain studies in an ODL institution.