Modeling of the Influence of Input AM Parameters on Dimensional Error and Form Errors in PLA Parts Printed with FFF Technology

As is widely known, additive manufacturing (AM) allows very complex parts to be manufactured with porous structures at a relatively low cost and in relatively low manufacturing times. However, it is necessary to determine in a precise way the input values that allow better results to be obtained in terms of microgeometry, form errors, and dimensional error. In an earlier work, the influence of the process parameters on surface roughness obtained in fused filament fabrication (FFF) processes was analyzed. This present study focuses on form errors as well as on dimensional error of hemispherical cups, with a similar shape to that of the acetabular cup of hip prostheses. The specimens were 3D printed in polylactic acid (PLA). Process variables are nozzle diameter, temperature, layer height, print speed, and extrusion multiplier. Their influence on roundness, concentricity, and dimensional error is considered. To do this, adaptive neuro-fuzzy inference systems (ANFIS) models were used. It was observed that dimensional error, roundness, and concentricity depend mainly on the nozzle diameter and on layer height. Moreover, high nozzle diameter of 0.6 mm and high layer height of 0.3 mm are not recommended. A desirability function was employed along with the ANFIS models in order to determine the optimal manufacturing conditions. The main aim of the multi-objective optimization study was to minimize average surface roughness (Ra) and roundness, while dimensional error was kept within the interval Dimensional Error≤0.01. When the simultaneous optimization of both the internal and the external surface of the parts is performed, it is recommended that a nozzle diameter of 0.4 mm be used, to have a temperature of 197 °C, a layer height of 0.1 mm, a print speed of 42 mm/s, and extrusion multiplier of 94.8%. This study will help to determine the influence of the process parameters on the quality of the manufactured parts.

PRACTICALAPPLICATION OF SIX SIGMA DMAIC METHODOLOGY IN EVALUATION OF PRE-ANALYTICAL QUALITY INDICATORS IN LABORATORY SETTINGS

The Six Sigma is a global management methodology that empowers clinical laboratories by better understanding of the quality in their laboratories and helps in improving quality and subsequently reducing laboratory costs. The objective of this prospective study was to practically apply Six Sigma on pre-analytical quality indicators i.e. pre-analytical phase errors of “Total Testing Process” in laboratory at PGIMER Satellite Centre, Sangrur (Punjab). In this study Six Sigma DMAIC ( Dene, Measure, Analyse, Improvement and Control) methodology was applied on routine Outpatient Department (OPD) samples received in hematology and biochemistry laboratory from May, 2020 to July, 2020 after institutional ethical committee permission. Pre-analytical phase errors were taken as pre-analytical quality indicators and were broadly classied in to requisition form and sampling errors. Sigma values and frequencies were calculated using Westgard formula present online at (www. westgard.com > six sigma calculators) for pre-analytical phase errors. After that Improvement phase of DMAIC methodology was done by training of laboratory technicians or personell involved in pre-analytical phase by audio-visual aids. Six Sigma values were calculated again after improvement phase. A total of 787 requisition forms and 1105 samples were studied before improvement phase and 889 requisition forms and 1400 samples were studied after improvement phase. Before improvement phase, overall requisition form errors were working at 2.9 sigma and sampling process was working at 3.1 sigma but after improvement phase, requisition form errors were working at 3.3 sigma and sampling process was working at 3.5 sigma. Before and after improvement phase the sample rejection rate in laboratory improved from 1.90% to 0.93% highlighting the benecial concept of six sigma in laboratory in pre-analytical phase leading to increased clinicians and patients'satisfaction and prevents unusual delaying of reports.

An Exploration of Grammatical Errors in Written English of Libyan EFL Students with Special Reference to Arabic as their First-Language

This study focuses on an exploration of grammatical errors in written English of Libyan EFL students with special reference to Arabic as their first language. One of the most important factors that negatively affect EFL students' writing is grammatical errors. Several studies have looked at grammatical errors made by learners of English as a foreign language. Some studies have reported that L1 interference has been indicated as an important factor in the commission of such errors. The current study explores the phenomenon of EFL learners making grammatical errors. It also examines whether the time spent learning English and using English in daily life positively affects a student's writing (fewer grammatical errors appear). In addition, it examines whether first language interference leads to errors by Arab learners in particular. Data was collected from 30 EFL participants studying in Faculty of Arts and Sciences Kufrah- Benghazi University by writing an essay, in English, about the students themselves, their families, and the cities where they live in. The subjects also answered a Grammar Recognition Test. The results of this study indicated that the subjects made 205 errors in 10 different grammatical areas, the highest number of errors found in using articles, the second was word/verb form errors, whereas the third was preposition-related errors. Furthermore, errors of active and passive voice, plural, word order, tense, 3rd person morpheme, and copula “be”. The analysis of these results indicated that the appearance of these errors was more common among learners who have less time learning the language as well as who use the language less in their daily life. Furthermore, the results also revealed that Arab EFL learners tend to translate directly from Arabic to English; in this case, L1 interference appears to be a reason for committing grammatical errors by the Arabs. Moreover, students 'lack of competence in English plays an important role in such an occurrence. The study concludes by giving some suggestions for teaching grammar and reducing the occurrence of errors in this area.

Variation propagation modeling in multistage machining processes considering form errors and N-2-1 fixture layouts

Variation propagation modeling of multistage machining processes enables variation reduction by making an accurate prediction on the quality of a part. Part quality prediction through variation propagation models, such as stream of variation and Jacobian-Torsor models, often focus on a 3-2-1 fixture layout and do not consider form errors. This paper derives a mathematical model based on dual quaternion for part quality prediction given parts with form errors and fixtures with N-2-1 (N>3) layout. The method uses techniques of Skin Model Shapes and dual quaternions for a virtual assembling of a part on a fixture, as well as conducting machining and measurement. To validate the method, a part with form errors produced in a two-stationed machining process with a 12-2-1 fixture layout was considered. The prediction made following the proposed method was within 0.4% of the prediction made using a CAD/CAM simulation when form errors were not considered. These results validate the method when form errors are neglected and partially validated when considered.

Adaptive spiral tool path generation for computer numerical control machining using point cloud

This paper reports a novel method to generate adaptive spiral tool path for the CNC machining of complex sculptured surface represented in the form of cloud of points without the need for surface fitting. The algorithm initially uses uniform 2 D circular mesh-grid to compute the cutter location (CL) points by applying the tool inverse offset method (IOM). These CL points are refined adaptively till the surface form errors converge below the prescribed tolerance limits in both circumferential and radial directions. They are further refined to eliminate the redundancy in machining and generate optimum region wise tool path to minimize the tool lifts. The NC part programs generated by our algorithm were widely tested for different case studies using the commercial CNC simulator as well as by the actual machining trial. Finally, a comparative study was done between our developed system and the commercial CAM software. The results showed that our system is more efficient and robust in terms of the obtained surface quality, productivity, and memory requirement.

TYPICAL ERRORS IN THE USE OF VERBAL FORMS AS A CONSEQUENCE OF GAPS IN SCHOOL EDUCATION

Verb is the most important part of speech because it is the syntactic and communicative center of the sentence. So the verb form errors is an important problem of culture of language. The mediaproducts (215 texts of different information genres) of first year students from the Institute of Journalism of the Taras Shevchenko National University of Kyiv was analyzed. A classification of tipical errors of verbs forms was suggested. Gaps in the school education (on the material of schools textbooks was analyzed) are the main cause of the following verb errors: verb-conjunction "to be" in the Present, verb nouns, passive verbs, passive participle, active participle, impersonal verbs, redundant constructs, lexical errors. The topics to supplement the school program of language was suggested. It is recommended to omit the verb-conjunction in the present tense; prefer verb forms, not nouns; use active constructions, not passive ones; not to use active present participles; the instrumental case of nouns should be used in the instrumental, not in the subjective sense; use adjectives as a predicate to describe the subject; not to use stationery and tautological constructions; distinguish the meaning of Ukrainian and Russian tokens.

Pembuatan Mobile Apps Berbasis Android Dengan Memanfaatkan Geolokasi Untuk Pengawasan Proses Belajar Siswa

Abstract-- Non-formal education often requires children to travel to have face-to-face meetings with their teachers. Meetings that take place often still use the attendance method manually by using the attendance form, thus allowing the loss of attendance form, errors in making attendance, and allowing fraud in doing attendance. Parents also cannot control the location of their children when attending meetings and do not know who the tutoring service is who is the teacher for their child. Based on these problems, a mobile application was created that can be used by students, teachers, and parents. Where the attendance process is done digitally by students by taking selfies through a smartphone camera. Teachers do not need to bother in recapitulating attendance and save time when the attendance process is carried out by students. Parents can find out the child's location, receive notifications when the child makes attendance, and download meeting attendance reports. The trial was carried out privately by providing input and seeing the output results whether it had gone well. Validation is done by conducting interviews with each user with the roles of parents, teachers, and students who have tried the system. Based on the results of trials and validation conducted with interviews, it was found that the system that has been created to supervise the student learning process is running well and helps parents in controlling face-to-face meetings between students and teachers through notifications received by parents when students make a presence, attendance reports that help teachers recap attendance data and help teachers make appointments with students easier to do. Keywords: education, attendance , mobile application, camera, notification Abstrak— Pendidikan non-formal sering kali mengharuskan anak bepergian untuk melakukan pertemuan tatap muka dengan guru mereka. Pertemuan yang berlangsung sering kali masih menggunakan metode presensi secara manual dengan menggunakan form presensi, sehingga memungkinkan terjadinya hilangnya form presensi, kesalahan dalam melakukan presensi, dan memungkinkan terjadinya kecurangan dalam melakukan presensi kehadiran. Orang tua juga tidak dapat mengontrol lokasi anak saat mengikuti pertemuan dan tidak mengetahui siapa jasa pengajar yang menjadi pengajar bagi anak mereka. Berdasarkan permasalahan tersebut dibuatkan sebuah aplikasi mobile yang dapat digunakan siswa, guru, dan orang tua. Dimana proses presensi dilakukan secara digital oleh siswa dengan mengambil foto selfie melalui kamera smartphone. Guru tidak perlu repot dalam melakukan rekapitulasi presensi kehadiran dan menghemat waktu saat proses presensi dilakukan siswa. Orang tua dapat mengetahui lokasi anak, menerima notifikasi ketika anak melakukan presensi, dan mengunduh laporan presensi pertemuan. Uji coba dilakukan secara pribadi dengan memberikan inputan dan melihat hasil output apakah telah berjalan dengan baik. Validasi dilakukan dengan cara melakukan interview kepada setiap pengguna dengan peran orang tua, guru, dan siswa yang telah mencoba sistem. Berdasarkan hasil uji coba dan validasi yang dilakukan dengan interview diperoleh bahwa sistem yang telah dibuat untuk melakukan pengawasan terhadap proses belajar siswa berjalan dengan baik dan membantu orang tua dalam mengontrol pertemuan tatap muka yang dilakukan siswa dengan guru melalui notifikasi yang diterima orang tua saat siswa melakukan presensi, laporan presensi yang membantu guru dalam merekap data presensi kehadiran dan membantu guru untuk membuat janji pertemuan dengan siswa menjadi lebih mudah untuk dilakukan. Kata kunci: pendidikan, presensi, aplikasi mobile, kamera, notifikasi

Analysis of Error Using Simple Past Tense on Recount Text Class VIII B Students of SMP Pelita Ngabang in the Academic Year 2019/2020 Landak District

This research aims at investigating the errors using simple past tense that is often done by students in the activity of writing sentences in simple past tense on the recount text of class VIII B of junior high school PELITA Ngabang in the academic year 2019/2020 Landak Regency. The study uses a qualitative research design. The research was carried out at junior high school PELITA Ngabang on November 22nd, 2019. The research subjects were VIII B amount of 20 students. After analyzing the errors of the 20 past forms in the recount text that were finished by 20 students there were 73 errors. Finally, the authors concluded that the past form errors in the recount text were the types of errors omissions, 19, 17%, type of errors addition 26, 02%, types of errors misformation 27, 39%, types of errors misordering 27, 39%.

الأخطاء في ترجمة اللغة الإندونيسية إلى اللغة العربية

This study aims to determine and describe the errors and their causes that occur in the results of the translation carried out by students of the 2016 Arabic Language Education class. The data of this study were obtained from the results of the students' translation which were taken using written test techniques. After the translation results are obtained, the error identification, error classification and error reconstruction are carried out. The forms of errors that occur in the translation results of the students are word choice errors, word omission errors, word addition errors, rule errors, and word form errors. As for the causes of errors, there are two things that underlie the errors found, namely interlingual transfers and intralingual transfers.