Historical development of the Puccinia triticina population in South Africa

In contrast to many other countries, the virulence and genetic diversity of the South African Puccinia triticina population before 1980, is unknown due to the absence of regular and systematic race analysis data and viable rust cultures. Herbarium specimens housed at the National Collection of Fungi, Biosystematics Unit, Plant Health and Protection, Agricultural Research Council, Pretoria, South Africa (SA), provided the opportunity to investigate the genetic development of the population using isolates collected between 1906 and 2010. Five sub-populations that survived between 21 and 82 years in the field, were found. While three of these could represent the original races that entered SA during European settlement, two appear to be recent exotic introductions into SA, most probably from other African countries. The demise of the three oldest sub-populations might be due to the release of resistant wheat cultivars. The population is clonal where new virulence develops through single step mutations and selection for virulence. Whereas a possible case of somatic hybridization was found, sexual reproduction appears to be absent in SA. This study confirmed the importance of annual surveys, not only in SA, but also in neighboring countries, to timeously detect the presence of new virulent races that could threaten wheat production in SA.

Probabilistic Safety Analysis for Loss of Offsite Power Accident in Dual-units Nuclear Power Plant

In order to explore the risk assessment method of the multi-unit nuclear power plant site, this paper selects the dual-unit plant nuclear site to analyze lose off-site power accident. By combining and improving the single-unit ET/FT model, to establish the dual-unit ET/FT model. From the analysis of the accident sequence, it can be concluded that the common cause failure of equipment is the main challenge faced by the dual-units. Especially the RPC sub-channel in the reactor protection system and the failure of emergency diesel engine circuit breaker. As can be seen from the high proportion of core CD occurring simultaneously in both uints, it has a great significance to study the risk of mult-units sites.

The Energy Efficiency of the Production and Conversion of Spring Triticale Grain into Bioethanol

According to the assumptions of Organisation for Economic Co-operation and Development OECD, the share of biofuels in the global transport sector is estimated to reach 15%–23% by 2050. The triticale can be used to produce bioethanol. The appropriate production process should generate as much renewable energy as possible per production unit. Plant production can be carried out in various tillage systems and using appropriate doses of nitrogen fertilization. The objective of this study is to compare the effect of traditional tillage system (TRD) and reduced (RED) tillage technology and nitrogen fertilizer (0, 40, 80, 120 kg N ha−1) on grain and bioethanol yield of spring triticale. The field experiment was performed in the south east of Poland (50°42′ N, 23°15′ E) on medium dystrophic typical brown soil. Based on research and calculations, the TRD system and between 40 and 80 kg ha−1 of N fertilizer are recommended for use in the cultivation of triticale for bioethanol production purposes. Such a variant will ensure a sufficient yield of grain (5.190 and 5.803 t ha−1), starch (3.462 and 3.871 t ha−1) and bioethanol (2487.3 and 2780.7 L ha−1) and good agronomic efficiency of N fertilizer (16.96 and 12.15 L of bioethanol per 1 kg of nitrogen (N) applied). The best ratio of energy efficiency of bioethanol production (EROI — Energy Return on (Energy) Investment or “net energy”) was recorded for the TRD system (1.138:1) and for the N fertilizer at 40 kg N ha−1 (1.144:1).

Piping Vibration of Multi-Treater System in OCU Process Plant

Acoustic-Mechanical coupling effect on piping dynamics is examined on site with measurement and analytical development. In this article, a multi-treater piping system in OCU (Olefin Conversion Unit) plant is subjected to investigation since significant piping vibration prevents the normal operation when some specific combinations of two treaters are operated. There is severe piping and structure vibration problem especially with increased capacity. Measurement in frequency domain shows two peaks so close each other to result in high amplitude in the piping system vibration by beating phenomenon. In search of solution, extra safety valve is manually opened to increase the acoustic volume which changes the acoustic natural frequency in the subjected piping system and decrease the vibration. Analytical study with acoustic analysis software is also conducted and it shows the same results as the actual piping dynamics. Based on the acoustic study, piping modification is designed and applied to the piping system and vibration improvement is achieved as expected.

Penentuan Interval Waktu Pemeliharaan Pencegahan pada Peralatan Sub-Unit RKC 3 di PTX Pabrik Tuban

PT X Tuban Plant has four plants (unit), namely Tuban I, Tuban II, Tuban III and Tuban IV. Each unit plant has three sub units, i.e., Crusher Operations Sub-Unit, Raw Mill, Kiln and Coal Mill (RKC) Sub-Unit and Finish Mill Sub-Unit. RKC 3 Sub-Unit in Tuban III has the highest number of equipment downtime and production loss. Therefore, it was necessary to optimize the time interval of preventive maintenance ( ) and total labor force as part of the company maintenance policy, would also fulfill the required reliability and availability of RKC 3 Sub-Unit. There were two steps in determining Tp optimum. The first step was to obtain the best distribution of the time between failures (TBF) and time to repair (TTR). The next step was to iterate the operating time (Ti) and Tp to determine the minimum preventive maintenance cost rate, reliability and maintainability.This iteration was applied to sub-units of RKC 3 that possesses a series system. Tp at the lowest rate of maintenance costs was the optimum Tp. The optimum Tp for RKC 3 Sub-Unit is 3743,28 hour. The preventive maintenance cost rate for optimum Tp is Rp33.100/hour and the reliability and availability of sub unit are 96,7% and 99,86% respectively.Keywords: reliability, availability, preventive maintenance cost rate, and preventive maintenance

PENGARUH SHIFT KERJA TERHADAP TINGKAT KELELAHAN KERJA DAN DAMPAKNYA TERHADAP KINERJA OPERATOR PRODUKSI ARV PT KIMIA FARMA (PERSERO) TBK. UNIT PLANT JAKARTA

Penelitian ini dilakukan untuk menganalisis pengaruh yang diberikan shift kerja terhadap tingkat kelelahan kerja dan dampaknya terhadap kinerja pada operator produksi ARV. Shift kerja merupakan pola waktu kerja yang ditentukan perusahaan bagi pegawainya yang terbagi menjadi pagi, siang dan malam. Sistem kerja shift dilakukan untuk menjamin optimalisasi kegiatan produksi dan pelayanan terhadap konsumen. Kelelahan merupakan perasaan tidak normal, lelah, lesu, hilang kendali, dan juga perasaaan lain yang sulit untuk didefinisikan karena kelelahan merupakan perasaan yang bersifat subjektif. Metode yang digunakan penelitian ini yaitu analisis jalur. Data yang digunakan dalam penelitian ini yaitu data sekunder berupa jadwal rotasi shift kerja dan data primer berupa kuesioner untuk mengukur tingkat kelelahan dan kinerja pegawai. Hasil uji yang dilakukan menunjukkan tidak ada pengaruh yang diberikan antara shift kerja terhadap tingkat kelelahan kerja dan dampaknya terhadap kinerja operator produksi ARV. Hal ini dibuktikan dengan hasil uji F dengan nilai Fhitung lebih kecil dibandingkan dengan nilai Ftabel (1.189 < 3.34). Kata Kunci : Kelelahan, Kinerja, Shift

Development and Use of the Risk-Based Joint Integrity (RBJI) Assessment Methodology

The ability to determine, using a uniform approach, which joints in a unit, plant or company represent the highest level of risk of leakage is extremely useful. Similarly to Risk-Based Inspection (RBI), Risk Based Joint Integrity (RBJI) allows the identification and allocation of resources to the joints that pose the greatest risk of failure. This ensures that the appropriate level of effort is placed in the most appropriate locations. This paper outlines a quantitative methodology for assessing the probability of failure for any given pressure boundary bolted joint. It allows rapid calculation across a range of joints without resorting to the typical qualitative, reactive, experienced-based methods commonly employed to assess risk of joint leakage (i.e.: waiting for the joint to leak in order for it to be labelled a bad actor). This methodology has been successfully employed in a number of applications over the past three years, such as justification of heat exchanger replacement (demonstrating the expected improvement in joint integrity) and assessment of residual risk associated with historic joint assembly practices. Future applications include assessment of risk and definition of acceptable residual risk during the project design phase in order to eliminate problematic joints prior to fabrication and using the methodology to reduce the time associated with leak-testing of piping systems during maintenance turn-around activities.