Functional clustering methods for resistance spot welding process data in the automotive industry

Quality assessment of resistance spot welding (RSW) joints of metal sheets in the automotive industry is typically based on costly and lengthy off-line tests that are unfeasible on the full production, especially on large scale. However, the massive industrial digitalization triggered by the industry 4.0 framework makes available, for every produced joint, on-line RSW process parameters, such as, in particular, the so-called dynamic resistance curve (DRC), which is recognized as the full technological signature of the spot welds. Motivated by this context, the present paper means to show the potentiality and the practical applicability to clustering methods of the functional data approach that avoids the need for arbitrary and often controversial feature extraction to find out homogeneous groups of DRCs, which likely pertain to spot welds sharing common mechanical and metallurgical properties. We intend is to provide an essential hands-on overview of the most promising functional clustering methods, and to apply the latter to the DRCs collected from the RSW process at hand, even if they could go far beyond the specific application hereby investigated. The methods analyzed are demonstrated to possibly support practitioners along the identification of the mapping relationship between process parameters and the final quality of RSW joints as well as, more specifically, along the priority assignment for off-line testing of welded spots and the welding tool wear analysis. The analysis code, that has been developed through the software environment R, and the DRC data set are made openly available online at https://github.com/unina-sfere/funclustRSW

Novel superabsorbent materials obtained from plant proteins

This work reviews the potential of plant protein-based materials as superabsorbent polymers (SAP). The review also discusses important topics of relevance for the current state of petroleum-based SAP and explains the background of the high water uptake of such materials. As diapers represent one of the most significant example of SAP applications, their industrial assemblying is highlighted. The research in absorbent materials has shown that treated and functionalized proteins may play a role in daily-care applications where super absorbency is required. Consequently, a description of proteins and the interactions that can take place within these natural polymers are reviewed. Protein sidestream candidates from biorefinery processes are listed and a further description of protein extraction mechanisms is given. This review also summarizes the results that have been obtained so far in the area of protein-based SAP materials. Finally, the challenges that protein-based SAPs face, as a possible candidate to replace petroleum-based ones, are discussed

Green Chemistry to Modify Functional Properties of Crambe Protein Isolate-Based Thermally Formed Films

Proteins are promising precursors to be used in productionof sustainablematerials with properties resembling plastics, although protein modificationor functionalization is often required to obtain suitable productcharacteristics. Here, effects of protein modification were evaluatedby crosslinking behavior using high-performance liquid chromatography(HPLC), secondary structure using infrared spectroscopy (IR), liquidimbibition and uptake, and tensile properties of six crambe proteinisolates modified in solution before thermal pressing. The resultsshowed that a basic pH (10), especially when combined with the commonlyused, although moderately toxic, crosslinking agent glutaraldehyde(GA), resulted in a decrease in crosslinking in unpressed samples,as compared to acidic pH (4) samples. After pressing, a more crosslinkedprotein matrix with an increase in beta-sheets was obtained inbasic samples compared to acidic samples, mainly due to the formationof disulfide bonds, which led to an increase in tensile strength,and liquid uptake with less material resolved. A treatment of pH 10+ GA, combined either with a heat or citric acid treatment, did notincrease crosslinking or improve the properties in pressed samples,as compared to pH 4 samples. Fenton treatment at pH 7.5 resulted ina similar amount of crosslinking as the pH 10 + GA treatment, althoughwith a higher degree of peptide/irreversible bonds. The strong bondformation resulted in lack of opportunities to disintegrate the proteinnetwork by all extraction solutions tested (even for 6 M urea + 1%sodium dodecyl sulfate + 1% dithiothreitol). Thus, the highest crosslinkingand best properties of the material produced from crambe protein isolateswere obtained by pH 10 + GA and pH 7.5 + Fenton, where Fenton is agreener and more sustainable solution than GA. Therefore, chemicalmodification of crambe protein isolates is effecting both sustainabilityand crosslinking behavior, which might have an effect on product suitability

funcharts: Control charts for multivariate functional data in R

Modern statistical process monitoring (SPM) applications focus on profile monitoring, i.e., the monitoring of process quality characteristics that can be modeled as profiles, also known as functional data. Despite the large interest in the profile monitoring literature, there is still a lack of software to facilitate its practical application. This article introduces the funcharts R package that implements recent developments on the SPM of multivariate functional quality characteristics, possibly adjusted by the influence of additional variables, referred to as covariates. The package also implements the real-time version of all control charting procedures to monitor profiles partially observed up to an intermediate domain point. The package is illustrated both through its built-in data generator and a real-case study on the SPM of Ro-Pax ship CO2 emissions during navigation, which is based on the ShipNavigation data provided in the Supplementary Material

Alcohol, binge drinking and associated mental health problems in young urban Chileans

OBJECTIVE: To explore the link between alcohol use, binge drinking and mental health problems in a representative sample of adolescent and young adult Chileans. METHODS: Age and sex-adjusted Odds Ratios (OR) for four mental wellbeing measures were estimated with separate conditional logistic regression models for adolescents aged 15-20 years, and young adults aged 21-25 years, using population-based estimates of alcohol use prevalence rates from the Chilean National Health Survey 2010. RESULTS: Sixty five per cent of adolescents and 85% of young adults reported drinking alcohol in the last year and of those 83% per cent of adolescents and 86% of young adults reported binge drinking in the previous month. Adolescents who reported binging alcohol were also more likely, compared to young adults, to report being always or almost always depressed (OR 12.97 [95% CI, 1.86-19.54]) or to feel very anxious in the last month (OR 9.37 [1.77-19.54]). Adolescent females were more likely to report poor life satisfaction in the previous year than adolescent males (OR 8.50 [1.61-15.78]), feel always or almost always depressed (OR 3.41 [1.25-9.58]). Being female was also associated with a self-reported diagnosis of depression for both age groups (adolescents, OR 4.74 [1.49-15.08] and young adults, OR 4.08 [1.65-10.05]). CONCLUSION: Young people in Chile self-report a high prevalence of alcohol use, binge drinking and associated mental health problems. The harms associated with alcohol consumption need to be highlighted through evidence-based prevention programs. Health and education systems need to be strengthened to screen and support young people. Focussing on policy initiatives to limit beverage companies targeting alcohol to young people will also be needed

Protein Nanofibrils and Their Hydrogel Formation with Metal Ions

Protein nanofibrils (PNFs) have been prepared by whey protein fibrillation at low pH and in the presence of different metal ions. The effect of the metal ions was systematically studied both in terms of PNF suspension gelation behavior and fibrillation kinetics. A high valence state and a small ionic radius (e.g., Sn4+) of the metal ion resulted in the formation of hydrogels already at a metal ion concentration of 30 mM, whereas an intermediate valence state and larger ionic radius (Co2+, Ni2+, Al3+) resulted in the hydrogel formation occurring at 60 mM. A concentration of 120 mM of Na+ was needed to form a PNF hydrogel, while lower concentrations showed liquid behaviors similar to the reference PNF solution where no metal ions had been introduced. The hydrogel mechanics were investigated at steady-state conditions after 24 h of incubation/gelation, revealing that more acidic (smaller and more charged) metal ions induced ca. 2 orders of magnitude higher storage modulus as compared to the less acidic metal ions (with smaller charge and larger radius) for the same concentration of metal ions. The viscoelastic nature of the hydrogels was attributed to the ability of the metal ions to coordinate water molecules in the vicinity of the PNFs. The presence of metal ions in the solutions during the growth of the PNFs typically resulted in curved fibrils, whereas an upper limit of the concentration existed when oxides/hydroxides were formed, and the hydrogels lost their gel properties due to phase separation. Thioflavin T (ThT) fluorescence was used to determine the rate of the fibrillation to form 50% of the total PNFs (t(1/2)), which decreased from 2.3 to ca. 0.5 h depending on the specific metal ions added

Greenhouse gas emissions of bio-based diapers containing chemically modified protein superabsorbents

Replacing the current mainly fossil-based, disposable, and non-biodegradable sanitary products with sustainable, functional alternatives is an industry priority. Suggested biobased alternatives require evaluation of their actual impact on greenhouse gas (GHG) emissions. We evaluated GHG emissions of biobased baby diapers as the most consumed sanitary product, using a biodegradable functionalized protein superabsorbent polymer (bioSAP) and compared them with currently used fossil-based counterparts. Assessment of the diapers also included estimated GHG emissions from the production of the biobased components, transport, and end-of-life combustion of these items. It was shown that only a few of the biobased diaper alternatives resulted in lower GHG emissions than commercial diapers containing fossil-based materials. At the same time, it was demonstrated that the production of the bioSAP via chemical modification of a protein raw material is the primary GHG contributor, with 78% of the total emissions. Reduction of the GHG contribution of the bioSAP production was achieved via a proposed recycling route of the functionalization agent, reducing the GHG emissions by 13% than if no recycling was carried out. Overall, we demonstrated that reduced and competitive GHG emissions could be achieved in sanitary articles using biobased materials, thereby contributing to a sanitary industry producing disposable products with less environmental pollution while allowing customers to keep their current consumption patterns

Vacuum-Formed Composites Based on a Polyolefin and a High Content of Biomass-Waste Fillers

Abstract A strategy to increase the biobased content and use of side-streams in plastic materials is to mix in biobased fillers available as inexpensive by-products. In line with this, herein, results on a polyolefin polymer with added wood powder (with or without a thermal treatment) and oat husk are presented, to make vacuum-formed products. The composite material is compounded, with or without a coupling agent, and then compression molded into sheets that are subsequently vacuum-formed. Despite a large content of fillers, the surface finish is in general smooth and uniform. The presence of filler increased, in general, the stiffness, and the use of the coupling agent is beneficial for the mechanical properties. The ductility and toughness, decreased in the presence of fillers, but the strain at break remained always larger than 10%. The fillers are all more hygroscopic than the polyolefin, which led to an increase in water uptake in the composites when immersed in water. The largest uptake, but still below 3.5% after 5 weeks, is observed for the material with oat husk. The results are overall promising, and open up for the use of biocomposites derived from industrial side-stream biofillers in vacuum-formed products.Abstract A strategy to increase the biobased content and use of side-streams in plastic materials is to mix in biobased fillers available as inexpensive by-products. In line with this, herein, results on a polyolefin polymer with added wood powder (with or without a thermal treatment) and oat husk are presented, to make vacuum-formed products. The composite material is compounded, with or without a coupling agent, and then compression molded into sheets that are subsequently vacuum-formed. Despite a large content of fillers, the surface finish is in general smooth and uniform. The presence of filler increased, in general, the stiffness, and the use of the coupling agent is beneficial for the mechanical properties. The ductility and toughness, decreased in the presence of fillers, but the strain at break remained always larger than 10%. The fillers are all more hygroscopic than the polyolefin, which led to an increase in water uptake in the composites when immersed in water. The largest uptake, but still below 3.5% after 5 weeks, is observed for the material with oat husk. The results are overall promising, and open up for the use of biocomposites derived from industrial side-stream biofillers in vacuum-formed products

High Capacity Functionalized Protein Superabsorbents from an Agricultural Co-Product: A Cradle-to-Cradle Approach

Synthesis of superabsorbent particles from nontoxic wheat gluten (WG) protein, as an industrial co-product, is presented. A natural molecular cross-linker named genipin (a hydrogenated glycoside) is used together with a dianhydride (ethylenediaminetetraacetic EDTAD), to enable the preparation of a material with a network structure capable of swelling up to approximate to 4000% in water and approximate to 600% in saline solution. This represents an increase in swelling by over 10 times compared to the already highly absorbing gluten reference material. The carboxylation (using EDTAD) and the cross-linking of the protein result in a hydrogel with liquid retention capacity as high as 80% of the absorbed water remaining in the WG network on extensive centrifugation, which is higher than that of commercial fossil-based superabsorbents. The results also show that more polar forms of the reacted genipin are more effectively grafted onto the protein, contributing to the swelling and liquid retention. Microscopy of the materials reveals extensive nanoporosity (300 nm), contributing to rapid capillarity-driven absorption. The use of proteins from agricultural industries for the fabrication of sustainable protein superabsorbents is herein described as an emerging avenue for the development of the next generation daily-care products with a minimal environmental impact