Shrinkable Self-Similar Structure Design

Origami techniques, as folding and unfolding, can be utilized in shrinkable structures. Especially when the crease pattern is rigid foldable, it can be treated as a mechanical linkage of rigid panels connected by hinges. Since rigid foldable crease patterns have the strong geometrical constraint of the facets not being able to stretch or bend, it is difficult to design new crease patterns, and variations of existing patterns are limited. However, it is known that there are cases where crease patterns can be made rigid foldable by adding some slits. This paper proposes a mechanical linkage that folds into a similar flat shape by adding slits. A method is presented of generating rigid foldable crease patterns in arbitrary polygons that fold smaller, and it is confirmed that structures that have a mechanism for shrinking can be generated from these crease patterns by using rigid thick panels and hinges.

COMPUTATIONAL-EXPERIMENTAL STUDY OF CONTACT INTERACTION OF BODIES WITH NEARLY FORM SURFACES

In many constructions, their elements are in contact with nominally matching (congruent) surfaces. In reality, this contact is disturbed due to deviations in the shape of these surfaces from the nominal. To study the effect of this perturbation on the distribution of contact pressure, the analysis of the stress-strain state of the body system of punched sheet-die is carried out. The middle element of this system deviates from the nominally flat shape. This causes a change in the contact pressure distribution. The proportionality between the clamping force and the level of contact pressure is also lost. The reliability and accuracy of the results obtained by numerical calculation have been experimentally confirmed. Keywords: stress-strain state; contact pressure; contact interaction; method of variational inequalities; Kalker variational principle; finite element method

Comparison of Different Methods For Effective Manual Chest Compression In Dental Chairs, During Cardiopulmonary Resuscitation (CPR): A Manikin Study

During cardiopulmonary resuscitation (CPR), almost commercially dental chairs lack sufficient stability to perform effective manual chest compression (MCC). In our previous study, our technique that stabilizing stool can significantly reduce vertical displacement in a dental chair’s backrest. This study demonstrates that the efficacy of different methods for stabilizing 3 types of dental chair with a flat or a severely curved backrest exterior for effective MCC. Vertical displacement of the dental chair’s backrest was recorded. The data was captured with three different stool positions (no stool, under MCC, under shoulders). Reduction ratios were calculated to evaluate the effectiveness of the stool positions. In all types of dental chair, the technique significantly reduced the vertical displacements of the backrest. The reduction ratio varied nearly 40% under the area for MCC and 65% under the shoulder with a severely curved backrest exterior. With a flat shape of dental chair, these ratios were around 90% versus without a stool. The technique is a firm support and reduce the displacement of any type of dental chair’s backrest for effective MCC.

Numerical Modelling of Liquid Film Spreading Dynamics over Smooth Vertical Surface under Isothermal Conditions

The paper presents numerical modelling of the liquid film spreading dynamics of the R21 (mol. fraction: 0.9) and R114 refrigerants mixture. We considered an outer flow along a round vertical cylinder at Reynolds number of 104 and various contact angles. The simulation was performed in OpenFOAM software on the basis of the volume of fluid (VOF) method. We have shown that the wetting front deforms at wetting angles of 30 and 50 degrees, and regular jets form. At the same time, it was demonstrated that at the wetting angle of 10 degrees the spreading front has practically a flat shape, but one may see some regular thickenings of the liquid film along the contact line of the front.

Inovasi Dan Pengembangan Produk Stik Kangkung Di Desa Dasan Tereng Kabupaten Lombok Barat

Kangkong can be processed into various types of snacks, one of which is kangkong sticks. Sticks are a type of pastry that has a long flat shape, has a savory taste, and has a crunchy texture. Kangkong sticks are one form of innovation for processed kangkong products. Kangkong sticks were once produced in Dasan Tereng Village, but are no longer produced. Based on the results of interviews and observations conducted by the P1000WB Entrepreneurship Community Service Program (Creation of 1000 New Entrepreneurs), several problems have been found in the kangkong stick product. These problems include; unvaried taste, unattractive packaging, narrow marketing scope, and mass production system. KKN Kewirausahaan made various efforts to re-elevate, as well as develop kangkong stick products into superior products in Dasan Tereng Village. The efforts that have been made are: (1) Providing innovation in the form of flavor variants, (2) Improvement of product packaging using standing pouches, designing, and giving logos, (3) Doing digital marketing and changing the production system to a purchased order (PO) system. The method used is observation, short interview, and literature study. This gives tangible results in the form of product sales which are quite high, exceeding the sales target, from 40 packs to 110 packs in one week.

Spleen: an organ of multiple shapes

Introduction: The spleen is located in the upper part of the abdominal cavity. As an organ, the spleen can have various shapes and size. Material and methods: The human spleen was studied in 273 cadavers (154 men and 119 women) who did not have diseases of the spleen. The shape of the spleen was analyzed based on splenic index, Michels classification. Results: The most common shape of the spleen in men is the elongated one. It was encountered in 79 (51.3%) cases out of 154. In women, the most common shape was the intermediate. It was encountered in 51 (42.9%) of the 119 cases. Based on Michels classification the clinoid (wedge) shape was encountered in 102 (37.74%) cases, triangular in 59 (21.83%) and tetrahedral in 30 (11.1%). In 30.26% the shape of the spleen couldn’t be classified according to Michels classification. In 21 cases (7.77%) the spleen had a flat shape; in 27 (9.99%) – dome-shaped; in 1 case (0,37%) – Z-shape; in 18 (6.66%) – round shape; in 6 (2.22%) – irregular shape; in 2 (0.66%) - shape with a node in the hilum; in 1 (0,37%) – rhomboid shape, in 2 (0,74%) – bilobed shape and in 4 cases (1,48%) – lobular shape. The splenic fissures located on the upper edge of the organ were found in 81 (29.91%) cases, and also on the lower edge - in 41 (14.02%) cases. In 13 (4.67%) cases fissures were encountered on both sides. In 148 (51.4%) cases the spleen had no fissures on its surface. Conclusions: The spleen has various shapes beyond the classical wedge, triangular and tetrahedral. All of these shapes do not represent a pathological finding but in certain situation may require further analysis and interpretation depending on the imaging technique and experience of the physician.

Penerapan Model ELPSA dengan Bantuan Alat Peraga Geoboard untuk Meningkatkan Aktivitas dan Hasil Belajar Siswa pada Materi Bangun Datar

The purpose of this research is to increase the activity and student learning outcomes on the flat shape material with the ELPSA model using geoboard props. This research method uses classroom action research. The subjects of this study were students of class VII A of SMP Negeri 2 Dompu, totaling 28 people. Data collection techniques using questionnaires, and tests. While the data analysis technique is descriptive quantitative and qualitative. The results of this study indicate that the application of the ELPSA model with the help of a geoboard tool on flat-shaped materials can improve student activities and learning outcomes. This is evidenced by the average increase in activity data of 55.36% in the first cycle, to 63.61% in the second cycle and increased to 74.49% in the third cycle. Data on the average increase in student learning outcomes from 55.06% in the first cycle, to 61.90% in the second cycle and increased to 67.41% in the third cycle. Based on the results of this study, teachers should always innovate to be able to motivate students' interest in learning and improve the quality of learning with varied learning models and appropriate teaching aids, so that student learning outcomes can be maximized.

Konsep luas daerah bangun datar sederhana melalui artefak Candi Borobudur untuk matematika sekolah dasar

Perubahan penting dalam pengajaran matematika perlu dilakukan untuk mengakomodasi perubahan berkelanjutan dalam demografi siswa di kelas rendah Sekolah Dasar pada kompetensi matematika. Guru harus mengkontekstualisasikan pembelajaran matematika dengan menghubungkan konten matematika dengan budaya dan pengalaman kehidupan nyata siswa kelas rendah pada tingkat Sekolah Dasar. Konsep matematika yang diajarkan di sekolah dasar ada hubungannya dengan pengalaman pribadi siswa dalam kehidupan sehari-hari. Sepanjang sejarah, matematika telah digunakan oleh orang-orang yang berbeda dalam berbagai cara. Aritmatika dan geometri digunakan untuk memenuhi kebutuhan sehari-hari masyarakat baik dalam budaya maupun sosial. Etnomatematika didefinisikan sebagai cara orang-orang dari berbagai budaya menggunakan matematika dalam kehidupan sehari-hari mereka. Konsep-konsep pembelajaran matematika yang dipelajari oleh siswa sekolah dasar adalah baru sebatas bangun datar sederhana. Luas bangun-bangun datar sembarang yang bentuknya tidak teratur atau panjang sisinya tidak sama, sebenarnya dapat ditelusuri melalui pemindahan atau pembentukan bagian-bagian bangun datar tersebut agar menyerupai bangun datar utamanya.The concept of the simple plane area through Borobudur Temple artifacts for elementary school mathematicsAbstractImportant changes in mathematics teaching need to be made to accommodate the continuing changes in the demographics of students in the lower grades of Primary Schools in mathematics competence. Teachers must contextualize mathematics learning by linking mathematics content to the culture and real-life experiences of low-grade students at the Elementary School level. Mathematical concepts taught in elementary schools have to do with students' personal experiences in everyday life. Throughout history, mathematics has been used by different people in a variety of ways. Arithmetic and geometry are used to meet the daily needs of society both culturally and socially. Ethnomathematics is defined as the way people from different cultures use mathematics in their daily lives. Mathematics learning concepts learned by elementary school students are just a simple flat shape. The area of any flat shape whose shape is irregular or the length of the sides is not the same can actually be traced through the removal or formation of the parts of the shape so that it resembles the main shape.