Pengaruh Komposisi Sn Dan Variasi Tekanan Kompaksi Terhadap Densitas Dan Kekerasan Komposit Cu-Sn Untuk Aplikasi Proyektil Peluru Frangible Dengan Metode Metalurgi Serbuk

Proyektil peluru terdiri dari tiga bagian yaitu jacket, nose, dan inti (core). Proyektil umumnya terbuat dari paduan timbal. Timbal mulai dikurangi penggunaannya dalam berbagai produk. Untuk mengatasi permasalahan tersebut telah dikembangkan jenis peluru yaitu peluru frangible. Salah satu paduan material yang dapat digunakan adalah paduan Cu-Sn. Proses pembuatan dilakukan dengan metode metalurgi serbuk dengan variasi komposisi 5, 10, dan 15 wt%Sn. Penambahan timah diharapkan dapat memberikan densitas dan kekerasan yang optimum pada komposit Cu-Sn. Sedangkan variasi tekanan kompaksi yang digunakan adalah 300, 400, dan 500 MPa. Sintering dilakukan pada temperatur 260°C selama 30 menit dengan atmosfer gas nitrogen. Berdasarkan hasil pengujian XRD, fasa yang terbentuk adalah Cu, Cu3Sn, dan Cu6Sn5, densitas tertinggi pada komposisi Cu-5 wt% Sn P=500 MPa sebesar 7,446 g/cm3 dan memiliki porositas terendah sebesar 14,586%. Hasil pengujian kekerasan tertinggi pada komposisi Cu-15 wt% Sn P=500 MPa sebesar 83 HRF, nilai kekuatan tekan dan modulus elastisitas tertinggi pada Cu-15 wt% Sn P=500 MPa sebesar 275,72 MPa dan 59,43 GP

Experimental and Numerical Studies of Secondary Injection in Nozzle Divergence for Thrust Augmentation

Thrust augmentation in rocket engines using secondary injection in the diverging part of a nozzle is an innovative extension of after burners. This technique finds application in single stage to orbit propulsion devices, where the nozzle has to work at varying ambient pressures. Experimental and numerical studies have been conducted with varying cross flow and injection conditions to analyse the performance augmentation in a 2D nozzle. Schlieren images and wall pressure data are obtained from the experiment. Simulations are con-ducted using a HLLC scheme based finite volume solver. A detailed description of flow physics resulting due to the introduction of sonic angled jet into expanding supersonic flow is presented. It is found that the injection angle, pressure and main flow pressure have notable influence in the performance of the nozzle

Multi Party Distributed Private Matching, Set Disjointness and Cardinality Set Intersection with Information Theoretic Security

In this paper, we focus on the specific problems of Private Matching, Set Disjointness and Cardinality Set Intersection in information theoretic settings. Specifically, we give perfectly secure protocols for the above problems in n party settings, tolerating a computational ly unbounded semi-honest adversary, who can passively corrupt at most t < n/2 parties. To the best of our knowledge, these are the first such information theoretically secure protocols in a multi-party setting for all three problems. Previous solutions for Distributed Private Matching and Cardinality Set Intersection were cryptographical ly secure and the previous Set Disjointness solution, though information theoretically secure, is in a two party setting. We also propose a new model for Distributed Private matching which is relevant in a multi-party setting

Recalling the sonic perception of visually impaired people of Surabaya’s urban parks

Urban parks in a developing country hardly accommodatepeople with disability. The objective of this study is to investigate thepossibility of improving urban parks using the perception of visuallyimpaired people of urban parks’ sonic environment. This study wasconducted off-site the urban park using a questionnaire survey with twogroups of participants: sighted people (35 participants) and visuallyimpaired people (35 participants). The analysis was conducted usingsemantic analysis of the word used for explaining the sonic environment. This study shows that the visually impaired participants explained thesonic environment with more terminologies (56 terminologies for visuallyimpaired participants and 32 terminologies for sighted participants). Itindicates the engagement with the sonic environment is higher for thevisually impaired participants compared to the sighted participants. Ingeneral, the visually impaired participant perception of urban parksrepresents a similar terminology, but with more perception compared to thesighted participants, i.e., safety, directivity, and space. The later stage is touse the on-site method to validate and enrich this finding to arrive at thedesign proposition for the improvement of urban parks

Mapping ergonomics application to improve SMEs working condition in industrially developing countries: a critical review

In industrially developing countries (IDC), small and medium enterprises (SMEs) account for the highest proprotion of employment. Unfortunately, the working conditions in SMEs are often very poor and expose employees to a potentially wide range of health and safety risks. This paper presents a comprehensive review of 161 articles related to ergonomics application in SMEs, using Indonesia as a case study. The aim of this paper is to investigate the extent of ergonomics application and identify areas that can be improved to promote effective ergonomics for SMEs in IDC. The most urgent issue found is the need for adopting participatory approach in contrast to the commonly implemented top-down approach. Some good practices in ergonomics application were also revealed from the review, e.g. a multidisciplinary approach, unsophisticated and low-cost solutions, and recognising the importance of productivity. The review also found that more work is still required to achieve appropriate cross-cultural adaptation of ergonomics application. Practitioner Summary: Despite continuous efforts in addressing ergonomics issues in SMEs of IDC, workers are still exposed to poor work conditions. We reviewed factual-based evidence of current ergonomics application to inform future strategies of ergonomics in IDC, using Indonesia as a case study

Value Chain Implementation in Rural-Scale Integrated Coconut Farming System in North Sulawesi Province, Indonesia

The value of coconut production in North Sulawesi reaches almost 10% of Indonesia’s total coconut production, and more than 95% is managed by farmers. The main problem in coconut development is that the management of coconut cultivation is still traditional, and the quality of the products produced is still low, so that coconut commodities that are multipurpose relatively have no added value. The economic value of coconut is still very dependent on primary products, namely coconut seeds and copra. To increase farmers‘income, the solution that can be taken is to implement the value chain in integrated coconut farming by diversifying coconut products. This is a review chapter that aims to present the implementation of value chain analysis approach and formulate the strategic development of integrated coconut farming system on a rural scale in the North Sulawesi province. Implementation of the value chain by diversifying coconut commodities can provide added value. By managing an integrated coconut farm that produces 3–5 processed products, the economic value of coconut will increase by about 5–6 times. Several issues become obstacles in the development of the value chain, including the lack of farmer participation in the modern chain, weak market power and market access, weak contractual relationship strength, and weak agricultural sector development orientation in the provision of employment

Antalogi puisi: karya anak-anak bangsa dari Papua

Antalogi puisi karya anak-anak bangsa dari Papua merupakan salah satu bentuk apresiasi Balai Bahasa Papua, Badan Pengembangan dan Pembinaan Bahasa, Kementerian Pendidikan dan Kebudayaan terhadap anak-anak bangsa yang memiliki keterampilan menulis sastra, terutama puisi. Hal ini dilakukan mengingat pemahaman masyarakat terhadap konsep estetika masih kurang. Puisi dalam buku ini merupakan hasil karya sastra siswa-siswi sekolah dasar dan sekolah menengah pertama yang mengikuti sayembara penulisan puisi bagi siwa SD dan SMP se-Papua dan Papua Barat

Correlation Between Organizational Commitment and Employee Performance When Working From Home During the Covid-19 Pandemic

The aim of this study was to examine the correlation between organizational commitment and performance in employees working from home in Surabaya. A quantitative descriptive approach was used. 151 participants were recruited through purposive sampling. All participants were employees with work domiciles in Surabaya who worked from home during the Covid-19 pandemic. Data were collected using questionnaires. The performance instrument was compiled based on the theory of Bernardin &amp; Russel which consists of six aspects namely: (i) quality; (ii) quantity; (iii) timeliness; (iv) cost-effectiveness; (v) the need for supervision; and (vi) interpersonal impact. Meanwhile, the organizational commitment instrument was based on Mayer and Allen's theory which consists of three aspects, namely: (i) affective; (ii) continuance; (iii) normative. Data were analyzed using Pearson Correlation. The results indicated that there was a significant positive relationship between organizational commitment and the performance of employees in Surabaya who worked from home during the Covid-19 pandemic. Keywords: organizational commitment; performance; employees; Covid-1