Finite element modeling of ROPS in static testing and rear overturns

Even with the technological advances of the last several decades, agricultural production remains one of the most hazardous occupations in the United States. Death due to tractor rollover is a prime contributor to this hazard. Standards for rollover protective structures (ROPS) performance and certification have been developed by groups such as the Society of Automotive Engineers (SAE) and the American Society of Agricultural Engineers (ASAE) to combat these problems. The current ROPS certification standard, SAE J2194, requires either a dynamic or static testing sequence or both. Although some ROPS manufacturers perform both the dynamic and static phases of SAE J2194 testing, it is possible for a ROPS to be certified for field operation using static testing alone. This research compared ROPS deformation response from a simulated SAE J2194 static loading sequence to ROPS deformation response as a result of a simulated rearward tractor rollover. Finite element analysis techniques for plastic deformation were used to simulate both the static and dynamic rear rollover scenarios. Stress results from the rear rollover model were compared to results from simulated static testing per SAE J2194. Maximum stress values from simulated rear rollovers exceeded maximum stress values recorded during simulated static testing for half of the elements comprising the uprights. In the worst case, the static model underpredicts dynamic model results by approximately 7%. In the best case, the static model overpredicts dynamic model results by approximately 32%. These results suggest the need for additional experimental work to characterize ROPS stress levels during staged overturns and during testing according to the SAE standard.     

Sectional notes

American Journal of Potato Research -     

Genetic variation in minerals,crude protein and structural carbohydrates of foliage in provenances of young plants ofProsopis cineraria (L.) Druce in India

Prosopis cineraria is an important species for aridzone agroforestry in India. Information on the chemical composition and nutritive value of the leaves of young trees that will be useful in screening the provenances, is lacking. Chemical composition (N, P, K, Ca, Mg, Na), crude protein, and structural carbohydrates (neutral detergent fibre, acid detergent fibre, cellulose, hemicellulose, and lignin) of the foliage of one-year-old plants of 31 provenances ofProsopis cineraria were determined. The seeds were collected from 16°50 N to 29°55 N latitude and 69°49 E to 78°03 E longitude in India, and grown at Hisar (29°10 N latitude, 75°46 E longitude and 215 m altitude). Mineral contents (except N and P), crude protein, and structural carbohydrates varied significantly (p<0.05) between provenances, and the greatest amount of N, P, crude protein, NDF, ADF and lignin contents were found in Hisar provenance. The in vitro dry matter digestibility varied from 18.2% in Gandhinagar provenance to 34.0% in that of Barmer provenance.     

Pharmacokinetics of flunixin meglumine in the cow

Plasma levels of flunixin were measured in heifers after a single intravenous injection (1.1 mg kg-1), using high performance liquid chromatography. Plasma concentration versus time curves were best described by a two compartment model. The distribution phase (alpha) half-life was 0.294 hours, the elimination phase (beta) half-life was 8.12 hours and the volume of distribution was 1050 ml kg-1.     

Control of Farm Flies in Malta—III. The effect of residual insecticide sprays on Musca domestica and Stomoxys calcitrans in the Maltese Islands

Abstract

Field trials to control flies on animal farms in Malta were held during 1973 with tetrachlorvinphos, iodofenphos, fenitrothion, bioresmethrin and dimethoate applied as cover sprays to walls and ceilings. Results were assessed by fly population counts (using sticky fly-paper traps exposed for 24 h at weekly intervals), bioassay tests and visual assessments of flies on individual farms. Tetrachlorvinphos gave the best results and was applied as a cover spray on 12 large animal farms in the northwestern part of Gozo during 1974. Results, using the same criteria as in the 1973 trials, indicated that, although high fly mortality was observed and deposits on walls remained toxic throughout the season, effective control of houseflies and stableflies was not achieved.

It is suggested that residual spraying alone on the larger animal farms was not sufficient to overcome the breeding potential of the flies and that a residual spraying campaign could only be successful if more extensively applied and supplemented by a comprehensive programme of farm hygiene improvement.     

Horses,saddles and riders: Applying the science

An enthusiastic crowd of 400 people gathered at Anglia Ruskin University in Cambridge, UK on 29 November 2014 for the second International Saddle Research Trust Conference on the theme of Horses, Saddles and Riders: Applying the Science. The conference was organised under the auspices of the Saddle Research Trust (SRT) which is a charitable organisation based in the UK established with the intention of stimulating and supporting research into the influence of saddles on the welfare, performance and safety of horses and riders using objective scientific methods. The SRT aims to provide a coordinated, focused approach to research in these areas, to facilitate publication of the findings in scientific journals and dissemination of the results to the equestrian world. This approach allows the SRT to act as a link between research, education and the industry. The trust supports research into all aspects of the interaction between the horse, saddle and rider. Areas of specific recent interest include studying welfare, performance and safety issues related to the use of a saddle, the role of the saddle in equine and human back problems, characterising behavioural issues of horses associated with saddle‐related discomfort, assessing the effects of saddle design on rider performance and health and designing saddles for disabled riders. Further information about the SRT is available on the website www.saddleresearchtrust.com . Sponsors of the conference were World Horse Welfare, a practical and forward‐thinking charity that believes in using scientific evidence to help guide its work, Amerigo saddlers, a company that advocates research as a basis for improving product design, the British Equestrian Federation (BEF) and Horse and Hound.     

Evaluation of uncalibrated preferential flow models against data for isoproturon movement to drains through a heavy clay soil

The uncalibrated predictive ability of four preferential flow models (CRACK‐NP, MACRO/MACRO_DB, PLM, SWAT) has been evaluated against point rates of drainflow and associated concentrations of isoproturon from a highly structured and heterogeneous clay soil in the south of England. Data were available for four plots for a number of storm events in each of three successive growing seasons. The mechanistic models CRACK‐NP and MACRO generally gave reasonable estimates of drainflow over the three seasons, but under‐estimated concentrations of isoproturon over a prolonged period in the first season and over‐estimated them in the two remaining seasons. CRACK‐NP simulated maximum concentrations of isoproturon over the first two events of each of the three seasons of 156, 527 and 24.4 µg litre^?1, respectively, and matched the observed data (465, 65.1 and 0.65 µg litre^?1) slightly better than MACRO (69.1, 566 and 58.5 µg litre^?1). Automatic selection of parameters from soils information within MACRO_DB reduced the emphasis on preferential flow relative to the stand‐alone version of MACRO. This gave a poor simulation of isoproturon breakthrough and simulated maximum concentrations were 0, 50.1 and 35.1 µg litre^?1, respectively. The capacity model PLM gave the best overall simulation of total drainflow for the first two events in each season, but over‐estimated concentrations of isoproturon (967, 808 and 51.3 µg litre^?1). The simple model SWAT represented total drainflow reasonably well and gave the best simulation of maximum isoproturon concentrations (140, 80.2 and 8.2 µg litre^?1). There was no clear advantage here in using the mechanistic models rather than the simpler models. None of the models tested was able to simulate consistently the data set, and uncalibrated modelling cannot be recommended for such artificially drained heavy clay soils. © 2001 Society of Chemical Industry