Kinematic flexibility allows bumblebees to increase energetic efficiency when carrying heavy loads

Foraging bees fly with heavy loads of nectar and pollen, incurring energetic costs that are typically assumed to depend on load size. Insects can produce more force by increasing stroke amplitude and/or flapping frequency, but the kinematic response of a given species is thought to be consistent. We examined bumblebees (Bombus impatiens) carrying both light and heavy loads and found that stroke amplitude increased in proportion to load size, but did not predict metabolic rate. Rather, metabolic rate was strongly tied to frequency, which was determined not by load size but by the bee’s average loading state and loading history, with heavily loaded bees displaying smaller changes in frequency and smaller increases in metabolic rate to support additional loading. This implies that bees can increase force production through alternative mechanisms; yet, they often choose the energetically costly option of elevating frequency, suggesting associated performance benefits that merit further investigation.

Fast truck-packing of 3D boxes

We present formulation and heuristic solution of a container packing problem observed in a household equipment factory’s sales and logistics department. The main feature of the presented MIP model is combining several types of constraints following from the considered application field. The developed best-fit heuristic is tested on the basis of a computational experiment. The obtained results show that the heuristic is capable of constructing good solutions in a very short time. Moreover, the approach allows easy adjustment to additional loading constraints.

Investigation of Redistribution of Pile Foundation Forces Under Successive Loading of Its Elements

Redistribution of pile foundation forces under successive loading of its elements was investigated under laboratory conditions. A segment of pile foundation model was taken for use in the case study. Load tests on the pile foundation model segment, without joining its elements (pile and plate, which turns into grillage) and based on different combinations of static loadings were conducted. This proved that the loading of a plate causes skin friction on some length of the pile side surface as well as providing additional loading and settlement. Test results have shown that application of successive elements enables the foundation to carry loads up to 13% higher than in the case of a standard pile foundation loading with the same settlement rates.

Strength Analysis of PGV-1000M Steam Generator Support

The paper presents the design of PGV-1000M steam generator support. It is shown that the load in the rolling support is distributed extremely unevenly, which is associated with the compliance of the support construction. It is demonstrated that under working loads only several rollers are used, the stresses in which exceed the yield strength. This can be an additional loading factor to be considered in the analysis of welding No. 111 failure.

Determination of the limiting load on tractor hydromounting by trailer

Analysis of the known technical solutions for the additional loading of tractor from the trailer has shown that they are ineffective. Their ineffectiveness is the complexity of the design and construction of interfering in hydro-mounting construction of tractor or trailer hitch frame. Also, reasonable reloaded on tractor hydromounting is not provided. In order to avoid these shortcomings towing additional loading device to the trailer with a hydraulic cylinder mounted on the frame of the trailer rotatable carriage was suggested. The tests showed that the maximum additional loading of the tractor from the trailer can not exceed 3900 N, which is not sufficient from the position of improving performance.