THE INFLUENCE OF SECTION FORM OF METAL STRUCTURE ELEMENTS ON CORROSION WEAR

The article provides the corrosion examples in metal structures, as well as their types. In most cases, metal structures are used in buildings with an aggressive environment. Corrosion is influenced by factors such as humidity, dust, various gases, technological process and etc. And also corrosion is influenced by the cross-sectional shapes which made the structural rods. There are given recommendations for the corrosion-resistant profiles use in metal structures and measures for their protection against corrosion. Keywords: corrosion, gas, dustiness, aggressive environment, operation, humidity, condensate, profile element, wear, destruction, durability, speed, section.

Children-menus in restaurants of Portuguese, Hungarian and Croatian shopping centres: A qualitative study

Background Families to eat out frequently use shopping centres and, there is evidence that children's menus are poor nutritional quality. Obesity rates have increased all over the world, and it has been associated to the observed out of home food consumption. This study aimed to characterise children's menus in shopping center restaurants in Portugal, Hungary and Croatia, as a preliminary study to further develop strategies to intervene. Methods An observational cross-sectional study was carried out in shopping centres in Portugal, Hungary and Croatia. Only the ones providing a children's menu were selected. Data collection tool was developed by the research team, consisting of a three-section form to identify and characterise the restaurant and analyses the quality of children's menu. Results Researcher visited 295 restaurants, from which only 69 provided a children's menu. From these 12 restaurants offered gifts associated with it. The most frequently featured items on the menu were hamburgers (22%), grilled or fried chicken (19%), nuggets (17%) and pizza (12%). Potato chips were the most frequent side dish option (33%). Only 11 restaurants offered vegetable soup or vegetables. Although water was available, a variety of soft drinks and sugary fruit juices were also options. Sweet dessert is a common part of the menu. Nutritional information is present in only 13% of the menus. Menu prices do not differ much, Portugal having the higher average (x ̅ = €5.35±1.45). Hungary had the lower average (x ̅ = €4.30±1.50) and Croatia the lowest range (min=€3.00, max=€7.40). Conclusions Children's menu options have poor quality. Shifting foods offered to children in restaurants has the potential to improve diet quality, reduce excess energy intake and promote healthy eating habits. Key messages European strategies are needed to promote children healthy food environment. Following aim is to develop and test balanced menus for children among food chains.

Studi Analitik Karakteristik Penampang Baja Profil-I

Paper ini menyajikan hasil studi analitik tentang besaran karakteristik penampang baja profil-I berupa modulus elastis (Sx) dan modulus plastis penampang (Zx). Faktor bentuk penampang, yang merupakan perbandingan nilai Zx terhadap Sx, merupakan besaran utama yang digunakan untuk menghitung kapasitas momen plastis penampang baja. Khusus untuk baja profil-I yang dibuat dengan metoda canai panas, pada bidang pertemuan antara bagian sayap dan bagian badan terdapat bagian penampang seperempat lingkaran cekung yang memberikan kontribusi untuk nilai total besaran karakteristik penampang. Dalam penelitian ini, besaran karakteristik penampang dihitung dan dianalisis dengan menggunakan besaran karakteristik penampang dasar persegi panjang dan lingkaran. Analisa hasil perhitungan menunjukkan bahwa bagian penampang seperempat lingkaran cekung tersebut memberikan kontribusi yang konsisten terhadap nilai luas, modulus elastis dan plastis penampang, yakni dalam rentang sebesar 1.0 – 4,7%. Dari hasil penelitian ini juga diperoleh bahwa faktor bentuk penampang untuk profil-I yang umum digunakan berada dalam rentang nilai 1,102 – 1,147. Perhitungan nilai faktor bentuk penampang dengan dan tanpa mengikutsertakan bagian penampang seperempat lingkaran cekung memberikan hasil yang hampir sama dengan selisih rata-rata sebesar 0,001. Modulus plastis penampang dapat dihitung dengan menggunakan formula sederhana yang diusulkan pada artikel ini dengan tingkat akurasi yang sangat baik dengan deviasi sebesar 1.2 %. Untuk semua jenis ukuran penampang profil-I, formula ini bisa digunakan untuk menghitung modulus plastis penampang secara lebih sederhana. This paper presents the results of an analytical study of the characteristics of the I-profile steel cross-section in the form of elastic modulus (Sx) and plastic section modulus (Zx). The shape factor of the section, which is defined as the ratio of the value of Zx to Sx, is the principal quantity used to calculate the plastic cross-section moment capacity. Specifically for I-profile steels made by the hot-rolled process, in the area of ​​the junction between the flange and the web, there is a concave cross-section that contributes to the total value of the section characteristic. In this study, the magnitude of the cross-sectional characteristics is calculated and analyzed using the magnitude of the basic cross-section characteristics of rectangles and circles. Analysis of the calculation results shows that the cross-section of the concave quarter circle provides a consistent contribution to the area, elastic and plastic section modulus, which is in the range of 1.0 - 4.7%. From the results of this study, it was also found that the shape factor for the I-profile commonly used is in the range of values ​​1.102 - 1.147. Calculation of the cross-section form factor values ​​with and without including the concave quarter circle gives results that are almost the same as the average difference of 0.001. The plastic modulus of the cross-section can be calculated using the simple formula proposed in this article with a very good degree of accuracy with a deviation of 1.2%. For all types of I-profile cross-section sizes, this formula can be used to calculate the plastic section modulus easily.

The application of the elastic tube with the specific cross section form in the linear peristaltic pump

The article presents a study of the tube form influence on performance of the peristaltic pump with the linearly placed tube and several pushers squeezing it in the transverse direction. The coupled numerical simulation of fluid flow and solid domain deformation was carried out using the software, based on the finite volume method. The cross sections with surface protrusions of two different types are considered for numerical simulation. The simulation results have shown that protrusions without a smooth transition at the tube walls reduce the compression ratio of the tube and therefore yield the flow rate reduce. Protrusions with s smooth transition at the tube walls on the contrary increase the flow rate in a high pressure range. Higher flow rate and pressure values achieved in the case of surface protrusions placed in the first compression region of the tube only. Comparison of pump characteristic curves shows that the use of tube surface protrusions can significantly increase the energy efficiency of the pump.

Nonlinear Analysis of Bending GFRP Tube Concrete Member

In order to study the factors that influence anti-bending mechanical properties of GFRP tube confined concrete beams and better applied to engineering, the influence of different thickness of GFRP tube, concrete strength grade, the section form and strength of steel were analyzed using finite element analysis software ABAQUS when the beam is in compression condition in this paper. The results showed that the bearing capacity of beams was improved by increasing the GFRP tube thickness, improving the core concrete strength and increasing steel area and strength. The numerical results were in good agreement with the experimental one. The anti-bending bearing capacity formula was in good agreement with the experimental results.