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This paper aims to propose and demonstrate a simple fiber optic sensor using a tapered plastic multimode fiber as a probe for measurement of calcium nitrate concentrations in de-ionized water.

The working mechanism is based on the observed increment in the transmission of the sensor that is immersed in calcium nitrate solution of higher concentration. The tapering of the plastic fiber is carried out by etching method using acetone, sand paper and de-ionized water.

Tapered fiber with diameter 0.45 mm gives the highest sensitivity of 0.028 mV/% due to better interaction between the evanescent field and the calcium nitrate solution with a good slope linearity of more than 98 per cent for a 1.07 per cent limit of detection in a straight probe arrangement. The use of calcium and nitrate ions within the sensing medium demonstrates the strong dependency of the sensor output trend on the electrolytic nature of the chemical solutions.

Demonstration of tapered plastic multimode fiber sensor probe for measurement electrolytic chemical solutions.

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.

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.

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.

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.

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.

Global and local processing is part of human perceptual organisation, where global processing helps extract the “gist” of the visual information and local processing helps perceive the details. Individual differences in these two types of visual processing have been found in autism and ADHD (Attention-Deficit Hyperactivity Disorder). Virtual reality (VR) has become a more available method of research in the last few decades. No previous research has investigated perceptual differences using this technology.

The objective of the research is to threefold: (1) identify if there is association between ADHD and autistic traits and the performance on the Rey-Osterrieth complex figure (ROCF) task, (2) investigate practical effects of using VR drawing tools for research on perceptual experiences and (3) explore any perceptual differences brought out by the three-dimensional nature of the VR. The standard ROCF test was used as a baseline task to investigate the practical utility of using VR as an experimental platform. A total of 94 participants were tested.

Attention-to-detail, attention switching and imagination subscales of autism quotient (AQ) questionnaire were found to be predictors of organisational ROCF scores, whereas only the attention-to-detail subscale was predictive of perceptual ROCF scores.

The current study is an example of how classic psychological paradigms can be transferred into the virtual world. Further investigation of the distinct individual preferences in drawing tasks in VR could lead to a better understanding of individual differences in the processing of visuospatial information.

This paper aims to develop an inexpensive, portable, sensitive and environmentally friendly electrochemical sensor to quantify trace metals.

A sensor was constructed by modifying carbon paste electrode for the determination of lead, cadmium and zinc ions using square wave anodic stripping voltammetry (SWASV). The modified electrode was prepared by inserting homogeneous mixture of 2-hydroxy-acetophenonethiosemicarbazone, graphite powder and mineral oil. Various important parameters controlling the performance of the sensor were investigated and optimized. Electrochemical behavior of modified electrode was characterized by cyclic voltammetry.

Modified carbon pastes electrodes showed three distinct peaks at −0.50, −0.76 and −1.02 V vs silver/silver chloride corresponding to the oxidation of lead, cadmium and zinc ions at the electrode surface, respectively. The highest peak currents for all the metal ions under study were observed in the phosphate buffer solution at pH 1 with a deposition time of 70 s. The sensor exhibited linear behavior in the range of 0.25-12.5 μg mL-1 for lead and cadmium and 0.25-10.0 μg mL⁻¹ for zinc. The limit of detection was calculated as 78.81, 96.17 and 91.88 ng mL⁻¹ for Pb2⁺, Cd2⁺and Zn2⁺, respectively. The modified electrode exhibited good stability and repeatability.

A chemically modified electrode with Schiff base was applied to determine the content of cadmium, lead and zinc ions in aqueous solutions using SWASV.

This study aims to optimize the structure of gold-sputtered U-shaped plastic fiber sensors.

A group of U-shaped Au-sputtered plastic optical fiber sensing probes with polishing angles of 45°, 90° and 135° is prepared.

The experimental results show that the spectral response and sensitivity of the sensor at 45°polishing angle is twice that of the sensor at 90°.

Due to the limitations of laboratory temperature and equipment, the overall effect has not reached the ideal, but the expected effect has been obvious. Experiments also optimize the sensor.

Optical fiber sensing has always been an indispensable part of various fields.

Sensor optimization is of great help to the progress of technology and the development of science and technology.

The authors have no conflicts of interest to disclose.

This study aims to analyze the transmission characteristics of a long-period grating (LPG) fabricated on plastic optical fibers (POFs) and its refractive index (RI) sensing.

The geometric optic method is used to analyze the factors affecting the transmission characteristics of an LPG on POFs. The RI sensing performances of unbent LPGs and U-bent LPGs fabricated on POFs with different diameters are evaluated experimentally.

This study shows that the transmission loss caused by LPG strongly depends on the structural parameters of LPG and the environmental RI. For the unbent LPG, the highest RI sensitivity of 1,015%/RI unit (RIU) was obtained in the RI range of 1.33–1.45. For the U-bent LPG without cladding, the highest RI sensitivities of 1,007 and 559%/RIU are obtained in the RI ranges of 1.33–1.40 and 1.40–1.45, respectively.

A geometric optic method is used to analyze the transmission characteristics for an LPG on POFs, and the RI sensing of the LPGs are studied experimentally. The results show the LPG has a good RI sensing performances and is with the features of low-cost, simple structure and easy fabrication.

A simple tapered plastic optical fiber (POF) sensor is proposed and demonstrated for measurement of uric acid concentrations in de-ionized water. The paper aims to discuss these issues.

The sensor operates based on intensity modulation technique as the tapered POF probe which was coated by a single walled carbon nonotubes polyethylene oxide (SWCNT-PEO) composite is immersed into the uric acid solution. The probe was fabricated using an etching method and has a waist diameter of 0.46 mm and tapering length of 10 mm.

As the concentration varies from 0 to 500 ppm, the output voltage of the sensor increases linearly from 6.13 to 7.35 mV with a sensitivity of 0.0023 mV/% and a linearity of more than 97.20 percent. The SWCNT-PEO composite coating increases the sensitivity of the proposed sensor due to the effective cladding refractive index, which increases with the coating and thus allows more light to be transmitted from the tapered fiber.

This is the first demonstration of the tapered POF sensor for measurement of uric acid concentrations in de-ionized water.

The purpose of this paper is to ascertain how total productive maintenance (TPM) has been implemented in large and medium size UK manufacturing companies, focusing on why such a programme was introduced, the activities involved, and the effectiveness and difficulties encountered during the process.

The aspects listed were based on a review of the literature. A case study approach was favoured to collect the necessary data. Companies were contacted, four of which responded favourably, and a protocol was developed to enable interviews to be carried out at each.

“Culture” was highlighted as the main obstacle to successfully implementing TPM; others were lack of awareness about the advantages of the programme, low employee skills and high cost. Two benefits gained by the four companies were a significant improvement in the availability and performance of the equipment within the plant and improved communication between employees. Additional benefits were financial improvement, reduced energy cost and increased employee morale and job satisfaction.

The number of companies that were willing to take part in the study was poor, thereby making it difficult to generalise the conclusions.

The results should help large and medium size organisations to better understand the TPM discipline, to facilitate its adoption and prioritise its practice. They also highlight the effectiveness and obstacles that can be encountered during the process.

The paper highlights the strong potential of TPM implementation programmes in affecting organisational performance improvements. The study also offers a beneficial source of information to organisations, which are still lagging far behind when it comes to TPM practices.

Automated flow line manufacturing systems are becoming more and more relevant in industry, especially in the food and beverage sector. Improving the efficiency of automated flow line manufacturing systems is the core objectives of all companies as measured by the overall equipment effectiveness (OEE) index. The purpose of this paper is to carry out an innovative micro downtime data collection and statistical analysis in the food and beverage sector; it introduces a numerical indicator called “Cost Performance Indicator-CPI” to estimate the performance improvement of investment activities. Moreover this analysis will be used as a basis to carry out a new simulative model to study micro downtime of automatic production lines. In addition, the presented micro downtime data collection and statistical analysis will be used to construct a new simulative model to support improvement activities.

Descriptive and statistical analyses are carried out about OEE, time to repair (TTR) and time to failure (TTF) data. The least efficient production line is identified and principal causes of inefficiency are investigated. Micro downtime (downtime lower than 15 minutes) covers 57 percent of inefficiency. Investigations are carried out into the three principal machines affected by this inefficiency. The study then investigates the causes of micro downtime of these machines using ad hoc data collection and analysis. The probability distributions of TTF and TTR are evaluated and an analysis of micro downtime causes and a cause-effect is carried out. The most attractive investment in terms of recoverable OEE (1.44 percent) and costs is analyzed through the calculation of a CPI. One of the conclusions is to recommend the introduction of a payback period with a variable contribution margin.

This study get the basis for the construction of a new simulative model based on ad hoc micro downtime probability distributions, applied in automated flow line manufacturing systems. It gives an effort to downtime analysis in automated production lines and a guideline for future analysis. Results of this study can be generalized and extended to other similar cases, in order to study similar micro downtime inefficiency of other production lines. The statistical analysis developed could also potentially be used to further investigate the relationship between the reliability of specific machines and that of the entire line.

The case study presents a new detailed micro downtime data collection and statistical analysis in the beverage sector with the application of a numerical indicator, the CPI, in order to drive future actions. In addition, the presented micro downtime data collection and statistical analysis will be used to construct a new simulative model to support improvement activities. Moreover, results can be generalized and used as a basis for other micro downtime analyses involving the main causes of inefficiency in automated production lines.

City has a continuous need to diversify its products and services to ensure longer tourists’ stays and a profitable tourism industry. Kuala Lumpur is one of the most popular cities in the world, and within its vicinity, Batu Caves are not only an important Hindu religious site, but also a popular tourist attraction. Guided by the four realms of experience dimensions (Pine and Gilmore, 1998), the purpose of this paper is to analyze 54 essays written by university students, to examine the experience of their visit to Batu Caves. The findings confirmed the application of all the four realm dimensions – entertainment, educational, esthetic and escapist – revealing both positive and negative aspects of the experience. Batu Caves may capitalize on the positive experiences as pointers to create an effective marketing communication, while negative experiences are opportunities to devise appropriate corrective measures, and perhaps further develop tourism products and services that would appeal to the visitors’ experience.

This study employed a qualitative research strategy to examine visitors’ experiences at Batu Caves using the four realms of experience theory as coined by Pine and Gilmore (1998). A total of 54 undergrads were asked to describe their visit to Batu Caves (Lucia-Palacios et al., 2016) providing a complete insight of their opinions, feelings and perceptions (Jüttner et al., 2013) using the essay writing method.

The authors discovered firm evidence of the theory’s application, revealing the expected four experiential dimensions in explaining experience at a cultural religious site, extending the description to include its positive and negative aspects, all of which are useful for destination management. The study points out a lot of aspects that must be managed by the site, such as the poor esthetic experience (e.g. smell, rubbish, graffiti, etc.), controlling the animal aggression (i.e. monkeys) and perhaps develop new products and services which could enhance some experiences (e.g. cultural escapism through cultural performances in which visitors could participate).

The main weakness of the research is perhaps the qualitative research work in which data were collected from essays written by the university students. Data of this nature prevent us from being able to generalize the findings and reflect on the experience to the general public.

Tourist stays in Kuala Lumpur could be enhanced by providing meaningful, deep and memorable experiences. Tourist attractions such as Batu Caves should continuously examine the experience that they provide to the visitors. Batu Caves’ management could continuously measure its tourists’ experience provisions, as tourists’ needs evolve over time. From the results they could revamp their products and services offering to ensure the sustainability of Batu Caves’ natural and cultural appeal among visitors and tourists alike.

The outcome provides a better understanding of the current tourism product and services at the destination that have an impact on a visitor’s experience. The findings will assist the Batu Caves’ management to revise and develop the products and service offerings to the visitors.