Microneedles (MNs) have been manufactured using a variety of methods from a range of materials, but most of them are expensive and time-consuming for screening new designs and making any modifications. Therefore, stereolithography (SLA) has emerged as a promising approach for MN fabrication due to its numerous advantages, including simplicity, low cost, and the ability to manufacture complex geometrical products at any time, including modifications to the original designs. This work aimed to print MNs using SLA technology and investigate the effects of post-printing curing conditions on the mechanical properties of 3D-printed MNs. Solid MNs were designed using CAD software and printed with grey resin (Formlabs, UK) using Form 3 printer (Formlabs, UK). MNs dimensions were 1.2 × 0.4 × 0.05 mm, arranged in 6 rows and 6 columns on a 10 × 10 mm baseplate. MNs were then immersed in an isopropyl alcohol bath to remove unpolymerized resin residues and cured in a UV-A heated chamber (Formlabs, UK). In total, nine samples were taken for each combination of curing temperature (35°C, 50°C, and 70°C) and curing time (5 min, 20 min, and 60 min). Fracture tests were conducted using a hardness apparatus TB24 (Erweka, Germany). MNs were placed on the moving probe of the machine and compressed until fracture. The optimization of the SLA process parameters for improving the strength of MNs was performed using the Taguchi method. The design of experiments was carried out based on the Taguchi L9 orthogonal array. Experimental results showed that the curing temperature has a significant influence on MN strength improvements. Improvement of the MN strength can be achieved by increasing the curing temperature and curing time.

Three fractions of tobacco waste (scrap, dust and midrib) were subjected to a high voltage electric discharge (HVED) assisted extraction procedure under different experimental conditions: solvent:solid ratio (300, 500, 700 mL/g), frequency (40, 70, 100 Hz) and treatment time (15, 30, 45 min), in order to study the influence of these conditions on the content of chlorogenic acid. The content of chlorogenic acid ranged from 1.54 to 3.66 mg/100 g for scrap, from 1.90 to 2.97 mg/100 g for dust, and from 2.30 to 3.38 mg/100 g for midrib extract, showing a strong dependence on the applied process parameters. The temperature change and the change in pH and electrical conductivity of the extracts after high voltage discharge treatment were also observed. The studied process parameters showed a statistically significant effect on the chemical and physical properties of the extracts from tobacco waste as well as on the content of chlorogenic acid, indicating the potential of HVED assisted processes in the separation of chlorogenic acid from tobacco industry waste. Multiple regression analysis was used to fit the results for the chlorogenic acid to a second order polynomial equation and the optimum conditions were determined.

Background: Diesel engine exhaust causes adverse health effects. Meanwhile, the impact of renewable diesel exhaust on human health is less known. In this study, nasal patency, pulmonary function, and self-rated symptoms were assessed in 19 healthy volunteers after two separate 3-hour exposures to renewable diesel (hydrotreated vegetable oil [HVO]) exhaust, and exposure to filtered air (FA) for comparison. The HVO exposures were generated with two modern non-road vehicles (2019) having either: 1) no aftertreatment system (HVOPM+NOx), or 2) an aftertreatment system containing a diesel oxidation catalyst and a diesel particulate filter (HVONOx). The exposure concentrations complied with current EU occupational exposure limits (OELs) of NO, NO2, formaldehyde, polycyclic aromatic hydrocarbons (PAHs), and future OELs of elemental carbon (EC) from 2023. Results: Exposure to HVOPM+NOx consisted of PM1 (≈90 µg m-3, 54 µg m-3 EC) and NOx (NO 3.4 ppm, NO2 0.6 ppm). The average total respiratory tract deposition of PM1 was 27 µg h-1. The deposition fraction of HVO PM1 was 40-50% higher compared to diesel exhaust PM1 from an older vehicle, due to smaller particle sizes of the HVOPM+NOx exhaust. Exposure to HVONOx consisted mainly of NOx (NO 2.0 ppm, NO2 0.7 ppm) with low level of PM1 (~1 µg m-3). Compared to filtered air, exposure to HVOPM+NOx and HVONOx caused higher incidence of self-reported symptoms (78%, 63%, respectively, vs. 28% for FA, p<0.03). Especially, exposure to HVOPM+NOx showed 40-50% higher eye and throat irritation symptoms. Compared to filtered air, a decrement in nasal patency was found for the HVONOx exposures (-18.1, 95%CI: -27.3 to -8.8 L min-1), and for the HVOPM+NOx (-7.4 (-15.6 to 0.8) L min-1). Overall, no change was indicated in the pulmonary function tests (spirometry, peak expiratory flow, forced oscillation technique), except a slight increase in FEV1/FVC after exposure to HVONOx.Conclusion: Short-term exposure to HVO exhaust below the EU OELs did not cause severe pulmonary function changes in healthy subjects. However, an increase in self-rated mild irritation symptoms, and mild decrease in nasal patency after two HVO exposures may indicate irritative effects from exposure to HVO exhaust from modern non-road vehicles below future OELs.

The press-fit process is an efficient, low-cost method for joining parts. The parts that must be joined interfere with each other’s occupation of space; therefore, contact dimensions and their tolerances influence the quality of the assembly. The traditional method for the selection of contact dimensions and their tolerances is based on engineering experience. The idea of the research work presented in this paper is to optimize the press-fit process at an early stage of development process, involving prediction and optimization of the joining force and consequently the prediction and minimization of the rejection rate. Accordingly, several finite-element (FE) simulations of the press-fit process for predicting the joining forces were conducted, considering input-parameter variations (material properties: yield stress, hardening exponent; geometry: shaft diameter, guide diameter of the core, functional diameter of the core; friction coefficient). Based on FE simulations and 47 different input-parameter-variation results, the empirical model for predicting the joining force using the response-surface methodology (RSM) was obtained. By using RSM and a stochastic Monte Carlo simulation, the rejection rate was also determined. The predicted and the actual rejection rates for selected process parameters were 1.4 % and 1.5 %, respectively. Consequently, the press-fit process can also be optimized to reduce the rejection rate using the same Monte Carlo simulation. The results of the analysis show that the rejection rate can be reduced from 1.4 % to 0.2 %.

Physics curricula around the world recognise energy as one of the core concepts in science (Duit, 2014), as it is fundamental in development of integrated scientific understanding of phenomena (Linn et al., 2006; National Research Council, 2012; Nordine et al., 2011). Importance of the energy concept is also recognised by PISA and TIMSS studies and is reflected in many science standards (National Research Council, 2012; Next Generation Science Standards, 2013). However, research about students’ energy conceptions keeps showing that students at all educational levels have significant difficulties with the concept of energy (Goldring & Osborne, 1994; Lawson & McDermott, 1987; Neumann et al., 2013; Pride et al., 1998). Concretely, students exhibit difficulties with understanding work-energy processes (Van Huis & Van den Berg, 1993), energy degradation and energy conservation (Goldring & Osborne, 1994; Liu & McKeough, 2005; Neumann et al., 2013). Thereby, a large number of studies detected conservation of energy as the most difficult aspect of the energy concept (Lindsey et al., 2012; Neumann et al., 2013; Van Heuvelen & Zou, 2001; Van Huis & Van den Berg, 1993). In fact, only a very few students develop deeper understanding of energy conservation until the time they finish secondary school (Herrmann-Abell & DeBoer, 2018). For purposes of improving the quality of teaching about energy, it is useful to identify possible sources of above-mentioned students’ difficulties. Firstly, it is important to note that many students’ difficulties with the energy concept may be related to students’ (mis)understanding of systems (Seeley et al., 2019; Van Heuvelen & Zou, 2001; Van Huis & Van den Berg, 1993). Consequently, students should be helped to recognize the importance of carefully choosing the physical system, if one wants them to gain a functional understanding of energy conservation (Lindsey et al., 2012; Seeley et al., 2019). Such system-based Abstract. Conventional teaching about the law of conservation of mechanical energy (LCME) often results with students trying to solve problems by remembering similar problems they already covered in classes. Consequently, many students fail to transfer their knowledge to simplest real-life problems. Therefore, a pre-test – post-test quasi-experiment was conducted to evaluate the effects of an alternative, system-based approach to teaching about LCME. The study included 70 upper-secondary students from the First Bosniak Gymnasium Sarajevo, Bosnia and Herzegovina. Firstly, all students learned about energy in a conventional way. Then they wrote a test on LCME and had three additional hours of teaching about this topic, where one group of students learned in line with the forces-variant of the system approach (e.g., discussing conservative and nonconservative forces) and the other group with the process-variant of the same approach (e.g., discussing system’s states and processes like in thermodynamics). For both variants, only three hours of system-based teaching proved to substantially improve the students’ level of LCME understanding compared to the level of understanding they had after conventional teaching. It follows that the system approach may work well at the upper-secondary level, if it is introduced through the scaffolding-andfading technique.

Objetivo: Discorrer sobre o impacto da Síndrome de Burnout em enfermeiros do setor de urgência e emergência. Metodologia: Trata-se de uma revisão integrativa da literatura, seguindo seis etapas: formação da hipótese ou indagação da pesquisa; amostragem ou busca na literatura; coleta de dados; análise dos estudos incluídos na revisão; interpretação e discussão dos resultados; apresentação da revisão integrativa. Resultados: Os 14 artigos considerados para este estudo foram descritos na tabela, contendo identificação os seguintes itens: título, autor / ano, base de dados, metodologia e resultados. Os resultados identificaram os principais sinais e sintomas de Burnout que acometem o profissional de enfermagem, bem como os fatores que causam impacto na qualidade de vida, e as características do setor de urgência e emergência que influenciam no desencadeamento da síndrome de Burnout. Conclusão: Conclui-se que, o setor de urgência e de um hospital é um local propicio as doenças psicossomáticas aos profissionais que trabalham neste ambiente.

Učbenik obravnava ergonomijo izdelkov tako z vidika razvojnega inženirja, ki mora v prvi vrsti seveda zagotoviti funkcionalnost izdelka, kot tudi z vidika oblikovalca - dizajnerja, ki naj poskrbi, da bo izdelek tudi estetsko dovršen. Namen učbenika ni podajanje empiričnih podatkov, temveč seznanitev z osnovnimi pojmi ter predstavitev medsebojnih relacij in priporočil, ki so lahko inženirjem in oblikovalcem v pomoč pri razvoju izdelkov s poudarjeno ergonomsko in estetsko vrednostjo. V drugi izdaji učbenika je dodano tudi povsem novo poglavje, ki obravnava inkluzivno oblikovanje in njegove najpomembnejše vidike. Ti v večini primerov sovpadajo z ergonomskimi vidiki razvoja izdelkov ob eni pomembni razliki. Pri razvoju izdelka s poudarjeno ergonomsko vrednostjo izdelek praviloma poskušamo kar se da prilagoditi bolj ali manj omejeni ciljni populaciji uporabnikov, cilj inkluzivnega oblikovanja pa je razvoj takšnih izdelkov, ki so primerni za čim širšo populacijo.

We present an application of generalized strong complete mappings to construction of a family of mutually orthogonal Latin squares. We also determine a cycle structure of such mapping which form a complete family of MOLS. Many constructions of generalized strong complete mappings over an extension of finite field are provided.