Wheeled tractors for agriculture and forestry. Roll-over protective structures (ROPS). Static test method and acceptance conditions

2015 ◽  
2018 ◽  
Vol 61 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Caleb M. Lindhorst ◽  
Roger M. Hoy ◽  
Santosh K. Pitla ◽  
Michael F. Kocher

Abstract. OECD static tests (Codes 4, 6, 7, and 8) for agricultural rollover protective structures (ROPS) have become accepted standards for evaluating the ability of these structures to protect the operator during tractor rollover events. The strength properties of some materials typically used in ROPS change because of cold weather embrittlement at low temperatures. The static ROPS tests lack the ability to evaluate the strength of these structures during cold weather. The use of the dynamic ROPS test is well noted as a means for proving cold weather embrittlement resistance properties. Unfortunately, application of the OECD dynamic ROPS test (Code 3) is restricted to tractors with unballasted mass greater than 600 kg and generally less than 6,000 kg. The analyses presented in this technical note were undertaken to evaluate the extension of the OECD Code 3 dynamic ROPS test to tractors with unballasted mass of 6,000 kg or more. Tractor unballasted mass and wheelbase data from 47 wheeled tractors tested at the Nebraska Tractor Test Lab from 2014 to 2016 were used to explore the possibility of using a dynamic test method for evaluating the ability of ROPS on tractors with unballasted mass greater than 6,000 kg to meet the safety requirements of agricultural tractor ROPS. The data were graphed and analyzed to determine the required pendulum drop height and energy values to be applied to the ROPS by extending the existing equations to tractors over 6,000 kg. For tractors over 6,000 kg mass, it was determined that pendulum drop heights were too great for practical use. Three pendulum masses were proposed for the dynamic ROPS test: a 2,000 kg pendulum for tractors with mass less than 7,000 kg, a 4,000 kg pendulum for tractors with mass of 7,000 kg or more and less than 14,000 kg, and a 6,000 kg pendulum for tractors with mass of 14,000 kg or more and less than 23,000 kg. Alternate equations were developed for the drop height of each pendulum to meet the energy requirements that are expected to provide similar permanent deflections as those obtained when using the static ROPS test when considering the effect of strain rates on material properties. Tests should be conducted to determine how the results (permanent deflections) from the proposed dynamic ROPS test compare with results from the accepted static ROPS tests. It is further proposed that dynamic testing be conducted with the tractor rigidly restrained in a manner similar to the static test to better account for the wide variety of available tires and mountings for each tractor model. Keywords: Energy, Impact test, Pendulum, Reference mass, ROPS, Tractors.


2019 ◽  
Vol 23 (2) ◽  
pp. 129-135
Author(s):  
Muhammad Ramli ◽  
Nur Ilham Situru ◽  
Muhammad Thamrin

Prediction of Acid Mine Drainage Forming using Method of Column Leaching Test. One of the environmental problems in coal mining activities is the formation of acid mine drainage. Prediction of the formation of acid mine drainage is important as an effort to control environmental impacts. Acid mine water occurs with interactions between potentially acid-forming material with oxygen, bacteria and water. Objective of study is to analyze the potential for acid mine drainage forming based on material characteristics. The research method was carried out using static and kinetic tests. The static test method classifies materials according to the ability to produce clean acids with observed parameters such as paste pH, total sulfur, Acid Neutralizing Capacity (ANC), Net Acid Generation (NAG), Maximum Potential Acid (MPA), and Net Acid Producing Potential (NAPP). The Kinetic test method predicts the rate of acid-forming of a material. The kinetic test uses the Column Leaching Test Method by using material with composition designed to represent field condition. The kinetic method parameters are pH, electrical conductivity, acidity, alkalinity, sulfate content, and dissolved metal content (Fe, Mn, and Cd). Results of the static test classified the material into NAF Non-Acid Forming (NAF), Potential Acid Forming (PAF) and Uncertain (UC) material categories. The results of the Column Leaching Method classified the material into categories of potential and no potential to form acid mine water. The columns that have the potential to form acid mine drainage occur in columns with large amounts of tonnage of PAF material or those in the upper layer so that it reacts with oxygen. The columns that have no potential to produce acid mine drainage in columns with PAF material are in the middle layer or mixed with NAF material.


2020 ◽  
Vol 17 (7) ◽  
pp. 708-718
Author(s):  
Anan KENTHAO ◽  
Wanchat SIRISARN ◽  
Pornpimol JEARRANAIPREPAME

The present study aimed to evaluate the acute toxicity effect of cypermethrin contaminated aquatic ecosystems by using a 30 days post-hatching fry of Nile tilapia as a test model. The control and six test experiments, each comprising 10 animals, were repeated three times and evaluated with the static test method. The lethal concentrations at 50 % (LC50) and 70 % (LC70) for 96 h were determined using the probit analysis. Behavioural and histological changes were observed in fish exposed with cypermethrin at both 96 h LC50 and 96 h LC70. The values of 96 h LC50 and 96 h LC70 were estimated at 32.496 and 40.311 ppb, respectively. The affected fish exhibited the loss of equilibrium with erratic and darting swimming movements, hyperactivity, secretion of mucous and increasing rate of opercula activity. Severity of histopathological lesions were related to concentration levels and exposure times. The histological changes of gill tissues included the swelling of epithelial cells and the fusion of secondary lamella. An enlargement of sinusoids, pyknotic nuclei, vacuole formation and degeneration in hepatic parenchyma were observed in liver. The degeneration of glomerulus combining with oedema of renal tubule was also noticed in kidney. No alter lesion was seen on skin tissue. The results in the present study suggest that low levels of cypermethrin in the aquatic environment may alter adverse effect on growth and development in Nile tilapia.


1976 ◽  
Vol 46 (2) ◽  
pp. 129-134 ◽  
Author(s):  
K. Chakravarti ◽  
G. J. Pontrelli

The various factors affecting static generation in carpets such as relative humidity, fiber type, shoe-sole material, carpet backing, and treadwear have been examined in this paper. Experiments to determine threshold level of static sensitivity in humans have been made. Critical evaluations of current carpet static test methods have been made, and the use of low voltage (discharge voltage) instead of maximum voltage value is suggested. A new carpet static test method using a motorized treadmill device has been described.


2013 ◽  
Vol 724-725 ◽  
pp. 1749-1753
Author(s):  
Qiu Mei Gao ◽  
Lai Wang ◽  
Ying Zhang

In this paper, we carried out low cyclic loading test over CFRP strengthened seismic-damaged RC frame named KJ-2 with the quasi-static test method, and compared the seismic performance with the same sections and materials RC frame named KJ-1 which was unstrengthened. We study the seismic performance such as hysteresis curve, skeleton curve, stiffness degradation, bearing capacity degeneration, displacement ductility, and energy dissipation capacity of the reinforced RC frame. On this basis, we analyzed the results of this test in order to obtain some guiding opinions for asymmetric span RC frames that strengthened by CFRP, and provide main preference basis or future national or industry standards.


Sign in / Sign up

Export Citation Format

Share Document