Experimental investigation of high speed milling of aluminium alloy

Sve veći zahtjevi kupaca za kvalitetnijim proizvodima prisilili su proizvodnu industriju da neprestano usavršava kontrolu kvalitete i tehnologije obrade. Jedan od osnovnih postupaka rezanja metala je glodanje. Cilj ovoga rada je istražiti optimalne parametre rezanja legure AlMgSi (EN-AW 6060), jedne od najčešće korištenih legura aluminija, primjenom čeonih glodala od neobloženog cementnog karbida. Analizirao se utjecaj geometrije alata (ugao zavojnice) i reznih uvjeta (brzina rezanja i veličina posmaka) na površinsku obradu tijekom brzog glodanja aluminijske legure. Djelovanje parametara na površinsku hrapavost ustanovljeno je analizom varijance (ANOVA). Analizirano je djelovanje parametara rezanja na indekse hrapavosti površine. Rezultati su prodiskutirani i procijenjeni.The customer´s growing demand for higher quality products has forced manufacturing industry to continuously progress in quality control and machining technologies. One of the fundamental metal cutting processes is milling. The aim of this study is to investigate optimum cutting parameters of AlMgSi alloy (EN-AW 6060), which is one of the most commonly used aluminium alloys, using uncoated cemented carbide end mills. The influence of tool geometry (helix angle) and cutting conditions (cutting velocity, and feed rate) on the surface finish produced during high speed milling of aluminium alloy have been investigated. The significance of the parameters on surface roughness has been established with analysis of variance (ANOVA). The cutting parameters regarding surface roughness performance indexes are analysed, and the findings are discussed and evaluated

Experimental investigation of high speed milling of aluminium alloy

Sve veći zahtjevi kupaca za kvalitetnijim proizvodima prisilili su proizvodnu industriju da neprestano usavršava kontrolu kvalitete i tehnologije obrade. Jedan od osnovnih postupaka rezanja metala je glodanje. Cilj ovoga rada je istražiti optimalne parametre rezanja legure AlMgSi (EN-AW 6060), jedne od najčešće korištenih legura aluminija, primjenom čeonih glodala od neobloženog cementnog karbida. Analizirao se utjecaj geometrije alata (ugao zavojnice) i reznih uvjeta (brzina rezanja i veličina posmaka) na površinsku obradu tijekom brzog glodanja aluminijske legure. Djelovanje parametara na površinsku hrapavost ustanovljeno je analizom varijance (ANOVA). Analizirano je djelovanje parametara rezanja na indekse hrapavosti površine. Rezultati su prodiskutirani i procijenjeni.The customer´s growing demand for higher quality products has forced manufacturing industry to continuously progress in quality control and machining technologies. One of the fundamental metal cutting processes is milling. The aim of this study is to investigate optimum cutting parameters of AlMgSi alloy (EN-AW 6060), which is one of the most commonly used aluminium alloys, using uncoated cemented carbide end mills. The influence of tool geometry (helix angle) and cutting conditions (cutting velocity, and feed rate) on the surface finish produced during high speed milling of aluminium alloy have been investigated. The significance of the parameters on surface roughness has been established with analysis of variance (ANOVA). The cutting parameters regarding surface roughness performance indexes are analysed, and the findings are discussed and evaluated

Preparation of the polypropylene fibres with content of photochromic pigments

U radu se opisuje utjecaj fotokromatskih pigmenata na predivost, istezljivost i svojstva pigmentiranih polipropilenskih (PP) vlakana. U eksperimentalnom radu upotrijebljene su komercijalne vrste PP vlakana i fotokromatski pigment (Photopia® Purple) kako bi se odredile mogućnosti njihove primjene za UV senzore. Ocijenjena su mehanička svojstva (prekidna čvrstoća i istezanje kod prekida te Youngov modul). Također je analiziran izgled vlakana, odnosno promatrana je površina i poprečni presjek ovih vlakana pod svjetlosnim mikroskopom. Dobiveni rezultati pokazuju mogućnost pripreme vlakana s udjelom fotokromatskih pigmenata.In this paper, the effect of photochromic pigments on spinnability, drawability and properties of pigmented polypropylene (PP) fibres is presented. The commercial types of PP and photochromic pigment (Photopia® Purple) were used in experimental work to determination of their possibilities in use as a UV sensor fibres. Mechanical properties (tenacity and elongation at break as well as Young’s modulus), thermo-mechanical properties and factor of average orientation of composite fibres were evaluated and discussed. The surface and cross-section of these fibres were monitored using the light microscope. The obtained results indicate the possibility of preparation of the fibres with photochromic pigments in mass

Research on Influence of Loading Speed of Structural Two-component Epoxy Adhesives on Adhesive Bond Strength☆

Abstract Adhesive bonds belong among a prospective technology of materials connecting, they are applied in many industrial branches when single applications use many advantages of these constructional bonds among which also good shear strength can be ranked. Just the shear strength of the adhesive bond belongs among factors determining an applicability of single adhesives. Standards describing the experimental determination of the adhesive bond shear strength specify the time which is needed for reaching the bond failure. For an extension of adhesives specification for given application the definition of the shear strength can be spread also of other speeds. The paper deals just with the determination of the time influence which is necessary for breaking a steel test adherent on the resultant shear strength of structural adhesives. An electron microscopy was used for an evaluation of fracture surfaces. The aim of the performed experiment is to describe the influence of changeable rate of deformation of the adhesive bond on the shear strength. From the result of the constructional carbon steel S235J0 testing the increase of the breaking strength and yield strength at increasing loading speed is obvious. At increasing loading speed the fall of the elongation of the adhesive bonded material occurred. From the results it is obvious that the loading speed of the adhesive bonds has a positive influence on the strength results of tested adhesive bonds. It came to the increase of the adhesive bond strength up of 21-57% at the speed 500 mm·min-1

ADAM19: A Novel Target for Metabolic Syndrome in Humans and Mice

Obesity is one of the most prevalent metabolic diseases in the Western world and correlates directly with insulin resistance, which may ultimately culminate in type 2 diabetes (T2D). We sought to ascertain whether the human metalloproteinase A Disintegrin and Metalloproteinase 19 (ADAM19) correlates with parameters of the metabolic syndrome in humans and mice. To determine the potential novel role of ADAM19 in the metabolic syndrome, we first conducted microarray studies on peripheral blood mononuclear cells from a well-characterised human cohort. Secondly, we examined the expression of ADAM19 in liver and gonadal white adipose tissue using an in vivo diet induced obesity mouse model. Finally, we investigated the effect of neutralising ADAM19 on diet induced weight gain, insulin resistance in vivo, and liver TNF- levels. Significantly, we show that, in humans, ADAM19 strongly correlates with parameters of the metabolic syndrome, particularly BMI, relative fat, HOMA-IR, and triglycerides. Furthermore, we identified that ADAM19 expression was markedly increased in the liver and gonadal white adipose tissue of obese and T2D mice. Excitingly, we demonstrate in our diet induced obesity mouse model that neutralising ADAM19 therapy results in weight loss, improves insulin sensitivity, and reduces liver TNF- levels. Our novel data suggest that ADAM19 is pro-obesogenic and enhances insulin resistance. Therefore, neutralisation of ADAM19 may be a potential therapeutic approach to treat obesity and T2D

Perceptions of ownership among new forest owners : A qualitative study in European context

Private forest owners possess a major part of Europe's forests. Therefore, their behaviour plays a significant role in the development and management of European forest resources. At the same time, forest owners' values and objectives are becoming more versatile. There is a need for further understanding of elements affecting forest owners' management behaviour. One aspect of potential impact is how forest ownership is perceived by the forest owners themselves. Understanding how they experience the ownership, especially on the psychological level, can provide new insights into forest owners' management behaviour and aid in planning better services to meet their needs. This paper aims to describe the new NIPF owners' perceptions of forest ownership by qualitative analyses drawn from 23 in-depth interviews covering different contextual settings in Europe. The theory of psychological ownership is used as a theoretical background. The aim is to examine, how psychological ownership is expressed and the ownership feelings are manifested in different forest owning contexts. The results illustrate what kind of ownership values new forest owners set for their forests and discuss how these affect their forest management behavior. At the same time the paper illustrate the potential of the social science approach in forest ownership research.Peer reviewe

The psychological science accelerator’s COVID-19 rapid-response dataset

In response to the COVID-19 pandemic, the Psychological Science Accelerator coordinated three large-scale psychological studies to examine the effects of loss-gain framing, cognitive reappraisals, and autonomy framing manipulations on behavioral intentions and affective measures. The data collected (April to October 2020) included specific measures for each experimental study, a general questionnaire examining health prevention behaviors and COVID-19 experience, geographical and cultural context characterization, and demographic information for each participant. Each participant started the study with the same general questions and then was randomized to complete either one longer experiment or two shorter experiments. Data were provided by 73,223 participants with varying completion rates. Participants completed the survey from 111 geopolitical regions in 44 unique languages/dialects. The anonymized dataset described here is provided in both raw and processed formats to facilitate re-use and further analyses. The dataset offers secondary analytic opportunities to explore coping, framing, and self-determination across a diverse, global sample obtained at the onset of the COVID-19 pandemic, which can be merged with other time-sampled or geographic data

A global experiment on motivating social distancing during the COVID-19 pandemic

Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e., a controlling message) compared with no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared with the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing. Controlled motivation was associated with more defiance and less long-term behavioral intention to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges

A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world