841 research outputs found

    User Friendly Framework for Measuring Product and Process Novelty in the Early Stages of Product Development

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    AbstractThis paper examines the innovation process in four Norwegian companies, all supplying the automotive industry with light weight structural components. Twelve representative product projects are categorized, together with people from product development in respective companies, according to product and process novelty. The main contribution from this study is twofold; first, a new framework and index for categorizing innovation across product and process newness is developed, second, putting empirical data into the framework demonstrates that product and process uniqueness does not seem to be dependent on amount of resources

    Digital Connections: Student Experiences in Online Language Exchanges

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    Exciting advances in technology have provided foreign language teachers with opportunities to connect students to native speakers of target languages. Much of the research in this area focuses on changes in proficiency or cultural sensitivity. Although valuable, the research is lacking in understanding students’ experiences online, including positive and negative feelings, challenges, as well as students’ overall opinions of the exchanges’ usefulness for learning. The present study used a mixed methods approach to examine the experiences of third-semester university students participating in online language exchanges with native speakers. A third-semester Spanish class at a large university consisting of 18 students was selected as a sample. Students were required to speak online with native Spanish speakers in the target language for 20 minutes each week. Students completed weekly surveys and a final survey, and three students were selected for semi-structured interviews. The data reveal common struggles that students face during online exchanges, methods students use for coping with these difficulties, areas of perceived growth, and social factors that affect students’ experiences. The article concludes with recommendations for what foreign language educators can do to support students in similar online exchanges

    Hidden in plain sight: Cryptic and endemic malaria parasites in North American white-tailed deer (Odocoileus virginianus)

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    Malaria parasites of the genus Plasmodium are diverse in mammal hosts, infecting five mammalian orders in the Old World, but were long considered absent from the diverse deer family (Cervidae) and from New World mammals. There was a description of a Plasmodium parasite infecting a single splenectomized white-tailed deer (WTD; Odocoileus virginianus) in 1967 but none have been reported since, which has proven a challenge to our understanding of malaria parasite biogeography. Using both microscopy and polymerase chain reaction, we screened a large sample of native and captive ungulate species from across the United States for malaria parasites. We found a surprisingly high prevalence (up to 25%) and extremely low parasitemia of Plasmodium parasites in WTD throughout the eastern United States. We did not detect infections in the other ungulate species nor in western WTD. We also isolated the parasites from the mosquito Anopheles punctipennis. Morphologically, the parasites resemble the parasite described in 1967, Plasmodium odocoilei. Our analysis of the cytochrome b gene revealed two divergent Plasmodium clades in WTD representative of species that likely diverged 2.3 to 6 million years ago, concurrent with the arrival of the WTD ancestor into North America across Beringia. Multigene phylogenetic analysis placed these clades within the larger malaria parasite clade. We document Plasmodium parasites to be common in WTD, endemic to the New World, and as the only known malaria parasites from deer (Cervidae). These findings reshape our knowledge of the phylogeography of the malaria parasites and suggest that other mammal taxa may harbor infection by endemic and occult malaria parasites

    New Method for Separation of Electrode Polarization Impedance from Measured Tissue Impedance

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    In this paper we have shown that electrode polarization impedance (EPI) can be separated from measured tissue impedance as long as the characteristic frequencies of EPI and tissue are not too close, so that the EPI is largely displayed as a separate dispersion. In 2-electrode measurements the EPI and sample are physically connected in series, and commonly modelled by equivalent components in series. We have calculated the parallel equivalent elements and converted the series connected EPI and sample to a parallel admittance model. By curve fitting on the converted model we have shown that this provides a new method for estimating the EPI with enhanced accuracy compared to similar techniques used on the impedance model

    A surrogate-assisted optimization approach for multi-response end milling of aluminum alloy AA3105

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    AbstractOptimization of the end milling process is a combinatorial task due to the involvement of a large number of process variables and performance characteristics. Process-specific numerical models or mathematical functions are required for the evaluation of parametric combinations in order to improve the quality of the machined parts and machining time. This problem could be categorized as the offline data-driven optimization problem. For such problems, the surrogate or predictive models are useful, which could be employed to approximate the objective functions for the optimization algorithms. This paper presents a data-driven surrogate-assisted optimizer to model the end mill cutting of aluminum alloy on a desktop milling machine. To facilitate that, material removal rate (MRR), surface roughness (Ra), and cutting forces are considered as the functions of tool diameter, spindle speed, feed rate, and depth of cut. The principal methodology is developed using a Bayesian regularized neural network (surrogate) and a beetle antennae search algorithm (optimizer) to perform the process optimization. The relationships among the process responses are studied using Kohonen’s self-organizing map. The proposed methodology is successfully compared with three different optimization techniques and shown to outperform them with improvements of 40.98% for MRR and 10.56% for Ra. The proposed surrogate-assisted optimization method is prompt and efficient in handling the offline machining data. Finally, the validation has been done using the experimental end milling cutting carried out on aluminum alloy to measure the surface roughness, material removal rate, and cutting forces using dynamometer for the optimal cutting parameters on desktop milling center. From the estimated surface roughness value of 0.4651 μm, the optimal cutting parameters have given a maximum material removal rate of 44.027 mm3/s with less amplitude of cutting force on the workpiece. The obtained test results show that more optimal surface quality and material removal can be achieved with the optimal set of parameters.</jats:p

    Variation in Nordic Work-Related Cancer Risks after Adjustment for Alcohol and Tobacco

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    Background: Alcohol and tobacco strongly increases the risk of cancers of the tongue, mouth, pharynx, larynx, and oesophagus, and are also established risk factors for cancer of the liver, colon, and rectum. It is well documented that these habits are unequally distributed among occupational groups. Most occupational cohort studies lack information on these potentially important confounders, and may therefore be prone to bias. Aim: The aim of the study is to present Nordic standardized incidence ratios (SIRs) for alcohol and tobacco related cancer by occupation, after adjustment for alcohol and tobacco, and to compare to the unadjusted SIRs. Material and Methods: The study is based on the Nordic Occupational Cancer (NOCCA) database. We used confirmatory factor analysis models for simultaneous analysis of the cancer sites related to alcohol and tobacco, to obtain factors that allow for computation of adjusted expected numbers from the reference rates. We then calculated adjusted SIRs for the relevant cancer sites for each occupation. Results: For some occupations and cancers, the changes of risk estimates were striking, from significantly high to significantly low and vice versa. Among Nordic farmers, unadjusted SIRs for cancer of the mouth and oesophagus were 0.56 (95% confidence interval (CI) 0.51-0.61) and 0.67 (CI 0.63-0.70), respectively. After adjustment, estimates changed to 1.10 (CI 1.01-1.21) and 1.16 (CI 1.10-1.22). Unadjusted SIR for pharynx cancer among wood workers was 0.83 (CI 0.75-0.91), adjusted SIR was 1.14 (CI 1.03-1.25). For larynx cancer, results in the opposite direction were seen: unadjusted SIR for economically inactive was 1.38 (CI 1.31-1.46) while the adjusted SIR was 0.91 (CI 0.86-0.96). Conclusions: Adjustment for the latent indicators of alcohol and tobacco consumption changed risk estimates for several occupations, gave a less confounded description of risk, and may guide in the identification of true risk factors.Peer reviewe

    Soil organic carbon and associated soil properties in Enset (Ensete ventricosum Welw. Cheesman)-based homegardens in Ethiopia

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    Enset (Ensete ventricosum Welw. Cheesman)-based homegardens have long been practiced as central elements of agricultural land management and food security in south and southwest Ethiopia. In contrast to the homegardens’ biodiversity and role in food security, soil quality has received little attention. Objective of this study was to assess soil quality parameters in typical homegardens in comparison with adjacent croplands, both under continuous management for >30 years. The study was undertaken at high (2200–2330 masl), mid (1799–1849 masl), and low (1349–1381 masl) elevation in the central Omo-Gibe basin, southwest Ethiopia. Through interviews of 49 randomly selected farm households, and soil sampling at six paired sites at high and mid elevations, and five paired sites of low elevation, we found that homegardens received the majority of household waste and manure and were less frequently tilled. By contrast, some, but not all, croplands occasionally received inorganic fertilizer. Homegarden soil had significantly greater (P < 0.05) soil organic carbon (SOC) concentrations than croplands. At 0–20 cm depth, SOC concentrations in homegardens (22.4–26.4 mg
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