How to motivate students to do a course project in design of experiments course from a web-based virtual learning material?

Purpose The purpose of this study is to develop a practical method for training students how to conduct statistical analysis and do a course project in design of experiments (DOEs) course through the Web-based virtual catapult simulation. Design/methodology/approach A step-by-step sequential DOE process for investigating the effects of controllable factors on quality characteristic responses was presented as a guideline for conducting a DOE course project. Each team was assigned to create an innovative teaching material and work on the term report by following the recommended guidelines for designing experiments through the Web-based virtual catapult simulation. Hypothesis was defined to test whether doing a course project based on this approach would impact students’ learning outcome. Findings The Web-based virtual material was an alternative technique for interactive teaching that could improve students’ understanding and achievement in DOE course projects. There was a significant difference in student learning and understanding before and after doing on the course project through the Web-based virtual catapult simulation. The students had improved communication and teamwork skills after following the recommended procedure for practicing DOEs. Practical implications Most students could effectively conduct designing experiments, carry out designed experiments, analyze data and gain valuable teamwork experience. After learning the DOE approach based on the catapult simulation, they enjoyed working on their course projects deploying to the innovative toys and other real-life situations with real measurements. Originality/value The use of Web-based virtual material, including catapult simulation, was an alternative technique for interactive DOE teaching to improve the students’ understanding and achievement in DOE course projects.

Response Surface Methodology for 30 kW PEMFC stack characterization

Hydrogen is a promising energy carrier to allow the reach of the zero-emission targets established for the next years. Polymeric Electrolyte Membrane FC are studied inside the HI-SEA laboratory of the University of Genoa, to assess the opportunities of this technology on marine applications. Here, 8 PEMFC stacks, sized 30 kW each for a total power installation of 240 kW, have been tested to draw guidelines for the best system design onboard ships and to deepen the know-how on the experimental management of the technology. During the tests, it was possible to observe the reciprocal influence of some parameters, which may influence the system efficiency. In this work, a statistical investigation is developed to quantify the cell voltage variation correlated to the values of temperature and current. This has been possible thanks to Design Expert (DE), a software developed by Stat-EASE, Inc. Through the Design of Experiment approach, it is possible to evaluate the significance of variables in the FC system, called factors. The experiment under consideration is also characterized by non-controllable factors, cause of disturbances that induce further variability in the response. Eventually, it was possible to analyse the significance of the parameters involved, to build a regression model by performing the analysis of variance with which the significant values are identified, and to assess the presence of outliers.

Analysis of control factors and surface integrity during wire-EDM of Inconel 718 alloy using T-GRA approach

In today’s competitive modern manufacturing sectors, there is a vital need of utter precision and rigorous processing using various manufacturing approaches that directly influences the cost and processing duration of mechanized materials in addition to the consistency of the finished products. Therefore, it’s essential to figure out the required output by adjusting the control factors of any machining techniques which resulted in optimal values of the desired outcome. In this study, machining evaluation and process optimization is carried out on volumetric extraction of material namely material removal rate (MRR), kerf obtained during the machining (KW) and surface roughness (SR) of Inconel 718 superalloy during CNC controlled wire- electrical discharge machining. Four controllable factors- pulse interval, wire speed, pulse duration and peak current are considered to investigate the influence on performance measures. Taguchi's L16 has been used to construct the set of experiments before physical experimental runs and most influencing factors have been evaluated using ANOVA. SEM images and EDXS analysis have been resorted to examine the morphology of Inconel 718. These findings assist in identifying the topography of the machined surface. Further, the optimum integration has been obtained for the best yield and recorded using grey relational analysis integrated with Taguchi’s technique (T-GRA). The unfamiliarity of the work is based on consideration of zinc coated thin wire electrode and Taguchi-Grey combined approach of modelling with four levels of experimental design.

Influence of duration of storage and pre-sowing electromagnetic treatment on the development of the primary root system of cotton seeds

Seeds of five Bulgarian cotton varieties, stored for one and two years, were subjected to five pre-sowing electromagnetic treatments with different intensity and duration of exposure. It was found that the selected values of controllable factors had stimulating effect on the total length and total mass of sprout and root. The total length of sprout and root increased by 7.5-16.4% (p<0.05), the total mass of sprout and root increased by 7.8-12.7% (p<0.05). The best treatment options were 1[U=(8…5)kV, τ =(15…35)s] and 4[U=(6…3)kV, τ =(5…25)s]. Electromagnetic treatments had stronger positive effect on seeds stored for one year. Compared to the untreated control, corresponding to each storage period, the electromagnetic impact had stimulating effect for both storage periods: for the total length of sprout and root the increase was by 7.6-21.1% and 2.3-11.0% at option 4; for the total mass of sprout and root it was by 10.8-16.5% at option 1 and 4.5-9.1% at option 4, respectively, at one-year and two-year storage of seeds. In comparison with the control Chirpan-539 variety, untreated seeds, one-year storage, higher values for both studied characteristics were found only for seeds stored for one-year: for the total length of root and sprout at the varieties Natalia, treatment options 1 and 4, Nelina and Helius, options 2 and 4 and Chirpan-539, option 1; for the total mass of root and sprout at the varieties Nelina, options 1, 2 and 3 and Chirpan-539, option 5. Compared to the untreated control corresponding to each variety, the stimulating effect of the pre-sowing electromagnetic treatment for the two characteristics was found for all varieties, for both storage periods. The Helius variety was the most responsive to the electromagnetic impact, with the strongest stimulating effect for both characteristics, at the one-year storage of seeds the total length of sprout and root increased most strongly by 34.8-43.9% at options 1, 4 and 2[U=(6…3)kV, τ =(15…35)s], and the total mass of sprout and root increased by 48.5% at options 1.

Key failure factors of start-up women owned SMEs in service sector in Kigali: a principal component analysis approach

Purpose This study aims to develop and test a framework for studying the failure of new women entrepreneurs in the small- and medium-sized enterprises (SMEs) sector. Design/methodology/approach Using a sample of 114 unsuccessful entrepreneurs in Kigali, Rwanda, this study aimed to identify key failure factors of women-owned SMEs. This study used mixed methods where quantitative data were analysed using the principal component approach with Varimax rotation to reduce the variables to only three clusters. Findings The study findings revealed that the failure of women-owned SMEs results from the entrepreneur’s inability followed by the enterprise incompetence, which are both internally controllable factors and the inauspicious business environment. These findings contribute to the validity of the dynamic capability theory by explaining how well internal and external factors must stay glued together to avoid failure among women-owned SMEs, something that was not yet previously well documented so far. Originality/value New SMEs are considered a noteworthy constituent of Rwandan development. Unfortunately, most new SMEs, in general, do not grow; their failure rate is high (70%), which raised many worries for both researchers and policymakers as to why this occurs at this stage of business growth. Therefore, to the best of the authors’ knowledge this paper is the first to analyse the reasons for the failure of Rwandan women-owned SMEs in the service sector. These findings are important because they suggest that policies designed to reduce the incidence of SMEs’ failure should take account of the two main factors influencing failure among women entrepreneurs.

A note on Variance-Sum Third Order Slope Rotatable Designs

Response Surface Methodology (RSM) is a collection of mathematical and statistical techniques useful for analyzing experiments where the yield is believed to be influenced by one or more controllable factors. Box and Hunter (1957) introduced rotatable designs in order to explore the response surfaces. The analogue of Box-Hunter rotatability criterion is a requirement that the variance of i yˆ(x)/ x be constant on circles (v=2), spheres (v=3) or hyperspheres (v 4) at the design origin. These estimates of the derivatives would then be equally reliable for all points (x , x ,...,x ) 1 2 v equidistant from the design origin. This property is called as slope rotatability (Hader and Park (1978)).Anjaneyulu et al (1995 &2000) introduced Third Order Slope Rotatable Designs. Anjaneyulu et al(2004) introduced and established that TOSRD(OAD) has the additional interesting property that the sum of the variance of estimates of slopes in all axial directions at any point is a function of the distance of the point from the design origin. In this paper we made an attempt to construct Variance-Sum Third Order Slope Rotatable in four levels. Keywords: Response Surface Methodology. Third Order Slope Rotatable Design; TOSRD (OAD), Variance-Sum Third Order Slope Rotatable Design.

A Case Study on the Deformation of Metro Foundation Pit in Silt Stratum in North China

Geological conditions of urban subway foundation pits are controllable factors in determining the deformation of pits. In this paper, the monitoring data and statistical data of a subway deep foundation pit in North China are presented and compared with those of Tianjin subway. The deformation characteristics of the proposed pit, open excavated with triple-layer steel supports, are introduced in detail. Based on the aforementioned information, the energy conservation equation of the mobilized strength design (MSD) method in which the compression deformation energy of internal support is considered is applied to predict the maximum lateral movement. The maximum lateral movement turns out to be 22.2 mm according to the improved MSD method, which is very close to the measured value.

Parkinsonism and dysautonomia with anti-CV2/CRMP5 associated paraneoplastic neurological syndromes mimicking multiple system atrophy: a case report

Background Paraneoplastic neurological syndromes (PNSs) are broad-spectrum disorders that can affect any part of the nervous system varying in core symptoms. Onconeural antibodies, including Hu, Yo, Ri, anti-CV2, amphiphysin, Ma2, and Tr are well-characterized and commonly used for the diagnosis of definite PNS. Generally, anti-CV2 antibodies have usually been associated with cerebellar ataxia, chorea, peripheral and autonomic neuropathies, myelopathy, optic neuritis, and retinitis. However, Parkinsonism has not been reported as the core symptom in patients with anti-CV2 antibodies. Case presentation We report a patient with anti-CV2 antibody manifested as Parkinsonism and autonomic dysfunction, which may lead to the diagnosis of multiple system atrophy with predominant Parkinsonism (MSA-P). A lumbar puncture examination was undergone to find a positive anti-CV2 antibody in cerebrospinal fluid. PET-CT showed no tumor. Immunotherapy was adopted and the symptoms were relieved for 5 months. However, with no evidence of tumor, he died after 8 months. Conclusions Our findings indicate that PNS with anti-CV2 antibody can be shown as MSA-P mimic. Considering that MSA is a neurodegenerative disease with a poor prognosis, screening for other treatable or controllable factors like PNS presented in this case is necessary when encountering a rapid progressive MSA-mimic patient.