Laboratory test sample representativity: an easily neglected aspect in consignment and its economic impact

ABSTRAK Penelitian ini bertujuan untuk mengetahui (1) dampak PT. Sarulla Operational Limited (SOL) Panas Bumi terhadap ekonomi di Kecamatan Pahae Julu, (2) untuk mengetahui dampak PT. Sarulla Operational Limited (SOL) Panas Bumi terhadap lingkungan (pencemaran air) di Kecamatan Pahae Julu. Metode yang digunakan dalam penelitian ini adalah metode penelitian deskriptif kuantitatif. Penelitian ini menggunakan data primer dan data sekunder. Populasi dalam penelitian ini adalah Daerah Aliran Sungai Batang Toru dan masyarakat Kecamatan Pahae Julu dari 19 desa yang berjumlah 12.343 jiwa. Penelitian ini dilakukan dengan metode survei dan wawancara. Hasil penelitian menunjukkan bahwa 1) ada dampak positif dari keberadaan PT. Sarulla Operational Limited (SOL) Panas Bumi terhadap ekonomi masyarakat seperti di bidang pekerjaan masyarakat memiliki peluang menambah penghasilan seperti membuka warung, rumah makan, kontrakan/kos-kosan, jual jasa sopir dan laundry sehingga dengan ini pendapatan masyarakat meningkat, 2) berdasarkan hasil penelitian mengenai lingkungan (pencemaran air) yang dilakukan dengan uji laboratorium, hasil penelitian menunjukkan bahwa air Sungai Batang Toru yang ada di sekitar PT. Sarulla Operational Limited (SOL) Panas Bumi tergolong tercemar dengan parameter yang diuji yaitu pH, BOD, DO, Posfat dan COD dan Nitrat tergolong tidak tercemar. Kata Kunci : Dampak Ekonomi, Dampak Lingkungan ABSTRAC This study aims to determine (1) the impact of PT. Sarulla Operational Limited (SOL) Geothermal on the economy in Sub Pahae Julu, (2) to know the impact of PT. Sarulla Operational Limited (SOL) Geothermal on the environment (water pollution) in District Pahae Julu. The method used in this research is descriptive quantitative research methods.This study uses primary data and secondary data. The population in this study is the Watershed District of Batang Toru and Pahae Julu community of 19 villages totaling12 343 inhabitants.The research was conducted by survey and interview. The results showed that 1) there is a positive impact of the presence of PT. Sarulla Operational Limited (SOL) Geothermal towards economic communities such as in the field of community work have the opportunity to increase revenue such as small store, restaurants, rent/boarding houses, selling services of a driver and laundry so that these people's income increases, 2) based on the results of research on the environment (water pollution) conducted by a laboratory test, the results showed that the waters of the Batang Toru around PT. Sarulla Operational Limited (SOL) Geothermal classified as contaminated with the parameters tested, namely pH, BOD, DO, Phosphate and Nitrate COD and relatively uncontaminated. Keywords: Economic Impact, Environmental Impact

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Durability studies of an indirect diesel engine run on raw palm kernel oil

International Journal of Technology and Management Research ◽

10.47127/ijtmr.v1i5.42 ◽

2020 ◽

Vol 1 (5) ◽

pp. 42-50

Author(s):

Godwin K. Ayetor ◽

Joseph Parbey ◽

Gabriel Osei

Keyword(s):

Diesel Engine ◽

Laboratory Test ◽

Vegetable Oil ◽

Diesel Fuel ◽

Palm Kernel ◽

Test Sample ◽

Lubricating Oil ◽

Durability Test ◽

Palm Kernel Oil ◽

Kernel Oil

This works considered the possibility of using raw palm kernel oil as an alternative to petroleum diesel fuel in a VW engine. At present, very little results on engine durability tests of palm kernel oil use as a fuel has been recorded in literature. A Four-stroke indirect injection diesel engine with capacity of 314,280x 10³mm³ and compression ratio 20.1:1 with constant water cooler was used for the investigation. The engine used for the experimentation is an indirect diesel engine, which is normally the type installed on agricultural engines. The engine was run alternatively for 100 hours on petroleum diesel and palm kernel oil respectively. After the durability test, sample of the lubricating oil was collected and sent for laboratory test. Viscosity, additives and metallic debris was analysed during the laboratory test for both fuel cases to determine wear. Visual inspection was also carried out to determine the state of the engine before and after each run. The engine run with petroleum diesel fuel was compared with that of the engine with palm kernel oil based on their fuel supply system and the lubricating oil analysis. The results showed that raw palm kernel oil can be used as a substitute to petroleum diesel in an indirect diesel engine without any significant damage. In terms wear, the vegetable oil even showed better performance due to its high lubricity compared with petroleum diesel fuel. It is recommended that a heating system be installed on the engine to run on palm kernel oil. Keywords: palm kernel oil; raw vegetable oil; straight vegetable oil; durability; lubrication oil.

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Calculations on compact disc cracking

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2020.0292 ◽

2021 ◽

Vol 379 (2203) ◽

pp. 20200292 ◽

Cited By ~ 1

Author(s):

Kaan Kendall ◽

Kevin Kendall

Keyword(s):

Stress Field ◽

Laboratory Test ◽

Edge Crack ◽

Tensile Force ◽

Test Sample ◽

Uniform Stress ◽

Central Crack ◽

Nominal Strength ◽

Uniform Stress Field ◽

Griffith Theory

The Griffith equation for brittle cracking has three problems. First, it applies to an infinite sheet whereas a laboratory test sample is typically near 100 × 100 mm. Second, it describes a central crack instead of the more dangerous and easily observable edge crack. Third, the theory assumes a uniform stress field, instead of tensile force application used in the laboratory. The purpose of this paper is to avoid these difficulties by employing Gregory's solution in calculating the crack behaviour of PMMA (Poly Methyl Meth Acrylate) discs, pin loaded in tension. Our calculations showed that axial disc loading gave nominal strengths comparable with Griffith theory, but the force went to zero as the crack fully crossed the disc, fitting experimental results. Off-axis loading was more interesting because the predicted strength was lower than in axial testing, but also gave unexpected behaviour at short crack lengths, where nominal strength did not rise indefinitely but dropped as crack length went below D/10, quite different from Griffith, where strength rose continuously as cracks were shortened. Such off-axis loading leads to a size effect in which larger discs are weaker, reminiscent of the fine fibre strengthening phenomenon reported in Griffith's early paper (Griffith 1921 Phil. Trans. R. Soc. Lond. A 221 , 163–198. ( doi:10.1098/rsta.1921.0006 )). This article is part of a discussion meeting issue ‘A cracking approach to inventing new tough materials: fracture stranger than friction'.

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