Prescience Life of Landing Gear Using Multiaxial Fatigue Numerical Analysis

AbstractFatigue failure, which occurs in many engineering components and structures in service, is actually attributed to the multiaxial loads. This study is aimed to estimate/ prescience life of main landing gear of a medium multi-utility aircraft under multiaxial loadings. In this analysis we studied the various loading conditions among them few are the spin-up, spring-back and lateral drift loading.The equivalent stress based multiaxial fatigue criteria (Sines and Crosslands) is employed for the determination of equivalent stress due to multiaxial loading and Palmgren Miner's theory used for calculating total damage and consequently the fatigue life. It is seen that the multiaxial fatigue numerical analysis render lower life than the maximum uni-axial life value

Estimation of Optimal Biomass Removal Rate Based on Tolerable Soil Erosion for Single-Pass Crop Grain and Biomass Harvesting System

As the demand for biomass feedstocks grows, it is likely that agricultural residue will be removed in a way that compromises soil sustainability due to increased soil erosion, depletion of organic matter, and deterioration of soil physical characteristics. Since soil erosion from agricultural fields depends on several factors including soil type, field terrain, and cropping practices, the amount of biomass that can be removed while maintaining soil tilth varies substantially over space and time. The RUSLE2 soil erosion model, which takes into account these spatio-temporal variations, was used to estimate tolerable agricultural biomass removal rates at field scales for a single-pass crop grain and biomass harvesting system. Soil type, field topography, climate data, management practices, and conservation practices were stored in individual databases on a state or county basis. Geographic position of the field was used as a spatial key to access the databases to select site-specific information such as soil, topography, and management related parameters. These parameters along with actual grain yield were provided as inputs to the RUSLE2 model to calculate yearly soil loss per unit area of the field. An iterative technique was then used to determine site-specific tolerable biomass removal rates that keep the soil loss below the soil loss thresholds (T) of the field. The tolerable removal rates varied substantially with field terrain, crop management practices, and soil type. At a location in a field in Winnebago county, Iowa, with ~1% slope and conventional tillage practices, up to 98% of the 11 Mg ha-1 total above-ground biomass was available for collection with negligible soil loss. There was no biomass available to remove with conventional tillage practices on steep slopes, as in a field in Crawford county, Iowa, with a 12.6% slope. If no-till crop practices were adopted, up to 70% of the total above-ground biomass could be collected at the same location with 12.6% slope. In the case of a soybean-corn rotation with no-till practices, about 98% of total biomass was available for removal at the locations in the Winnebago field with low slopes, whereas 77% of total biomass was available at a location in the Crawford field with a 7.5% slope. Tolerable removal rates varied substantially over an agricultural field, which showed the importance of site-specific removal rate estimation. These removal rates can be useful in developing recommended rates for producers to use during a single-pass crop grain and biomass harvesting operation. However, this study only considered the soil erosion tolerance level in estimating biomass removal rates. Before providing the final recommendation to end users, further investigations will be necessary to study the potential effects of continuous biomass removal on organic matter content and other biophysical properties of the soil

Gene introgression in assessing fitness costs associated with phosphine resistance in the rusty grain beetle

The current study investigates the fitness cost associated with phosphine resistance in the rusty grain beetle, Cryptolestes ferrugineus (Stephens), a problematic pest in the stored commodities that has developed strong resistance to fumigant phosphine. Three characterised insect strains: the susceptible (Ref-S), the strongly resistant (Ref-R), the introgressed resistant (Intro-R) and a segregating population (F25) derived from crossing the Ref-S and Ref-R strains were used in this study. Intro-R was developed by introgressing two phosphine resistance genes, cf_rph1 and cf_rph2 into Ref-S, aimed to reduce the influence of background genetic factors. Intro-R exhibited 592 × resistance to phosphine and homozygous for strong resistance allele, cf_rph2 (L73N). Two key fitness cost criteria, developmental time and fecundity, were assessed under optimal and suboptimal conditions (less favourable diet and low temperature). There was no significant difference in developmental time and fecundity between Ref-S and either Intro-R strain or F25 under optimal conditions. When challenged with a less favourable diet, cracked wheat + cracked sorghum (CW + CS), or exposed to a low temperature (22 °C), both Intro-R and Ref-S had similar developmental time and total numbers of F1 progeny, confirming the absence of significant fitness effects expressed in these conditions. Therefore, we conclude that strongly phosphine resistant C. ferrugineus are unlikely to incur potential fitness costs. This finding will have implications towards developing strategies to manage this pest

Improved climate simulations through a stochastic parameterization of ocean eddies

In climate simulations, the impacts of the sub-grid scales on the resolved scales are conventionally represented using deterministic closure schemes, which assume that the impacts are uniquely determined by the resolved scales. Stochastic parameterization relaxes this assumption, by sampling the sub-grid variability in a computationally inexpensive manner. This study shows that the simulated climatological state of the ocean is improved in many respects by implementing a simple stochastic parameterization of ocean eddies into a coupled atmosphere–ocean general circulation model. Simulations from a high-resolution, eddy-permitting ocean model are used to calculate the eddy statistics needed to inject realistic stochastic noise into a low-resolution, non-eddy-permitting version of the same model. A suite of four stochastic experiments is then run to test the sensitivity of the simulated climate to the noise definition, by varying the noise amplitude and decorrelation time within reasonable limits. The addition of zero-mean noise to the ocean temperature tendency is found to have a non-zero effect on the mean climate. Specifically, in terms of the ocean temperature and salinity fields both at the surface and at depth, the noise reduces many of the biases in the low-resolution model and causes it to more closely resemble the high-resolution model. The variability of the strength of the global ocean thermohaline circulation is also improved. It is concluded that stochastic ocean perturbations can yield reductions in climate model error that are comparable to those obtained by refining the resolution, but without the increased computational cost. Therefore, stochastic parameterizations of ocean eddies have the potential to significantly improve climate simulations

Testing Multi-Theory Model (MTM) in Predicting Initiation and Sustenance of Physical Activity Behavior Among College Students

Background: Most college students do not adequately participate in enough physical activity (PA) to attain health benefits. A theory-based approach is critical in developing effective interventions to promote PA. The purpose of this study was to examine the utility of the newly proposed multi-theory model (MTM) of health behavior change in predicting initiation and sustenance of PA among college students. Methods: Using a cross-sectional design, a valid and reliable survey was administered in October 2015 electronically to students enrolled at a large Southern US University. The internal consistency Cronbach alphas of the subscales were acceptable (0.65-0.92). Only those who did not engage in more than 150 minutes of moderate to vigorous intensity aerobic PA during the past week were included in this study. Results: Of the 495 respondents, 190 met the inclusion criteria of which 141 completed the survey. The majority of participants were females (72.3%) and Caucasians (70.9%). Findings of the confirmatory factor analysis (CFA) confirmed construct validity of sub-scales (initiation model: χ2 = 253.92 [df = 143], P \u3c 0.001, CFI = 0.91, RMSEA = 0.07, SRMR = 0.07; sustenance model: χ2= 19.40 [df = 22], P \u3c 0.001, CFI = 1.00, RMSEA = 0.00, SRMR = 0.03). Multivariate regression analysis showed that 26% of the variance in the PA initiation was explained by advantages outweighing disadvantages, behavioral confidence, work status, and changes in physical environment. Additionally, 29.7% of the variance in PA sustenance was explained by emotional transformation, practice for change, and changes in social environment. Conclusion: Based on this study\u27s findings, MTM appears to be a robust theoretical framework for predicting PA behavior change. Future research directions and development of suitable intervention strategies are discussed

An evolved disk surrounding the massive main sequence star MWC 297?

We present the results of the interferometric observations of the circumstellar disk surrounding MWC 297 in the continuum at 230 GHz (1.3 mm) and in the (J=2-1) rotational transitions of $^{12}$CO,$^{13}$CO and C$^{18}$O using the Submillimeter Array. At a distance of 250 pc, MWC 297 is one of the closest, young massive stars (M$_{\star}$ $\sim$10 M$_{\odot}$) to us. Compact continuum emission is detected towards MWC 297 from which we estimate a disk mass (gas+dust) of 0.07 M$_{\odot}$ and a disk radius of $\le$ 80 AU. Our result demonstrates that circumstellar disks can survive around massive stars well into their main sequence phase even after they have become optically visible. Complementing our observations with the data compiled from the literature, we find the submm dust opacity index $\beta$ to be between 0.1 and 0.3. If the emission is optically thin, the low value of $\beta$ indicates the presence of relatively large grains in the disk, possibly because of grain growth. We do not detect any CO emission associated with the continuum source. We argue that the $^{13}$CO emission from the disk is likely optically thin, in which case, we derive an upper limit to the gas mass which implies significant depletion of molecular gas in the disk. The mass of this disk and the evolutionary trends observed are similar to those found for intermediate mass Herbig Ae stars and low mass T Tauri stars.Comment: 4 pages, 3 Figures, accepted for publication in ApJ

Potential for using pheromone trapping and molecular screening in phosphine resistance research: Presentation

Phosphine resistance monitoring typically involves bioassays of beetles from population samples collected from grain storage facilities. Insects are classified into susceptible or resistant phenotypes based on mortality or survival at one or more discriminating doses. Although valuable, phenotype testing has several drawbacks. First, phenotype testing needs live insects, and considerable effort is required to collect and maintain them before testing. Second, population samples may contain multiple genotypes expressing different levels of resistance that may not be distinguishable using discriminating dose bioassays. Third, collections are likely to be focussed around grain storages to maximise sampling success. Recent research shows that several key pests are actively dispersing through flight. The availability of commercial pheromone lures and recent advances in molecular screening provide an opportunity to provide information on resistance gene frequencies more broadly across the landscape. This approach is proving to be a valuable adjunct to traditional resistance testing in Australia.Phosphine resistance monitoring typically involves bioassays of beetles from population samples collected from grain storage facilities. Insects are classified into susceptible or resistant phenotypes based on mortality or survival at one or more discriminating doses. Although valuable, phenotype testing has several drawbacks. First, phenotype testing needs live insects, and considerable effort is required to collect and maintain them before testing. Second, population samples may contain multiple genotypes expressing different levels of resistance that may not be distinguishable using discriminating dose bioassays. Third, collections are likely to be focussed around grain storages to maximise sampling success. Recent research shows that several key pests are actively dispersing through flight. The availability of commercial pheromone lures and recent advances in molecular screening provide an opportunity to provide information on resistance gene frequencies more broadly across the landscape. This approach is proving to be a valuable adjunct to traditional resistance testing in Australia

Latarjet Surgery Leads to Decreased Rates of Subjective Instability Compared to Bankart Repair with Concomitant Remplissage

Background: Predictive factors for performing remplissage concomitantly with arthroscopic Bankart repair include the presence of humeral or glenoid defects \u3e11% and/or revision surgery. International and societal consensus statements support these findings, as surgeons recommend the Latarjet procedure for patients with significant glenoid bone loss (\u3e15-20%) while remplissage is recommended for patients with off-track or engaging Hill-Sachs lesions without significant glenoid bone loss. While several studies have compared outcomes between Latarjet surgery and remplissage, these studies have only evaluated patients with engaging Hill-Sachs lesions, not consecutive patient cohorts indicated for each surgery. Purpose: To compare rates of recurrent instability, re-operation, revision, and return to play (RTP), as well as patient-reported outcomes including the American Shoulder and Elbow Surgeon Score (ASES), Single Assessment Numeric Evaluation (SANE), and Oxford Shoulder Instability Score (OSI) between Latarjet surgery and arthroscopic labral repair plus remplissage surgery (Remplissage) patients

Utility of biotechnology based decision making tools in postharvest grain pest management: An Australian case study

A major concern for the Australian grain industry in recent years is the constant threat of resistance to the key disinfestant phosphine in a range of stored grain pests. The need to maintain the usefulness of phosphine and to contain the development of resistance are critical to international market access for Australian grain. Strong levels of resistance have already been established in major pests including the lesser grain borer, Rhyzopertha dominica (F.), the red flour beetle, Tribolium castaneum (Herbst), and most recently in the rusty grain beetle Cryptolestes ferrugineus (Stephens). As a proactive integrated resistance management strategy, new fumigation protocols are being developed in the laboratory and verified in large-scale field trials in collaboration with industry partners. To aid this development, we have deployed advanced molecular diagnostic tools to accurately determine the strength and frequency of key phosphine resistant insect pests and their movement within a typical Australian grain value chain. For example, two major bulk storage facilities based at Brookstead and Millmerran in southeast Queensland, Australia, were selected as main nodes and several farms and feed mills located in and around these two sites at a scale of 25 to 100 km radius were selected and surveyed. We determined the type, pattern, frequency as well as the distribution of resistance alleles accurately for two major pests, R. dominica and T. castaneum. Overall, this information along with the phenotypic data, provide a basis for designing key intervention strategies in managing resistance problems in the study area.A major concern for the Australian grain industry in recent years is the constant threat of resistance to the key disinfestant phosphine in a range of stored grain pests. The need to maintain the usefulness of phosphine and to contain the development of resistance are critical to international market access for Australian grain. Strong levels of resistance have already been established in major pests including the lesser grain borer, Rhyzopertha dominica (F.), the red flour beetle, Tribolium castaneum (Herbst), and most recently in the rusty grain beetle Cryptolestes ferrugineus (Stephens). As a proactive integrated resistance management strategy, new fumigation protocols are being developed in the laboratory and verified in large-scale field trials in collaboration with industry partners. To aid this development, we have deployed advanced molecular diagnostic tools to accurately determine the strength and frequency of key phosphine resistant insect pests and their movement within a typical Australian grain value chain. For example, two major bulk storage facilities based at Brookstead and Millmerran in southeast Queensland, Australia, were selected as main nodes and several farms and feed mills located in and around these two sites at a scale of 25 to 100 km radius were selected and surveyed. We determined the type, pattern, frequency as well as the distribution of resistance alleles accurately for two major pests, R. dominica and T. castaneum. Overall, this information along with the phenotypic data, provide a basis for designing key intervention strategies in managing resistance problems in the study area