Ice breaking by a high-speed water jet impact

Ice breaking has become one of the main problems faced by ships and other equipment operating in an ice-covered water region. New methods are always being pursued and studied to improve ice-breaking capabilities and efficiencies. Based on the strong damage capability, a high-speed water jet impact is proposed to be used to break an ice plate in contact with water. A series of experiments of water jet impacting ice were performed in a transparent water tank, where the water jets at tens of metres per second were generated by a home-made device and circular ice plates of various thicknesses and scales were produced in a cold room. The entire evolution of the water jet and ice was recorded by two high-speed cameras from the top and front views simultaneously. The focus was the responses of the ice plate, such as crack development and breakup, under the high-speed water jet loads, which involved compressible pressure ${P_1}$ and incompressible pressure ${P_2}$ . According to the main cause and crack development sequence, it was found that the damage of the ice could be roughly divided into five patterns. On this basis, the effects of water jet strength, ice thickness, ice plate size and boundary conditions were also investigated. Experiments validated the ice-breaking capability of the high-speed water jet, which could be a new auxiliary ice-breaking method in the future.

Estimating Microbial Population Data from Optical Density

The spectrophotometer has been used for decades to measure the density of bacterial populations using the turbidity expressed as optical density – OD. However, the OD alone is an unreliable metric and is only proportionately accurate to cell titers to about an OD of 0.6. The relationship between OD and cell titer depends on the configuration of the spectrophotometer, the length of the light path through the culture, the size of the bacterial cells, and the cell culture density. We demonstrate the importance of plate reader calibration to identify the exact relationship between OD and cells/ml. We use four bacterial genera and two sizes of micro-titer plates (96-well and 384-well) and show that the cell/ml per unit OD depends heavily on the bacterial cell size and plate size. We applied our calibration curve to real growth curve data and conclude the cells/ml – rather than OD – is a metric that can be used to directly compare results across experiments, labs, instruments, and species.

MECHANICAL PRORERTIES OF EXPOSED COLUMN BASE CONNECTIONS FOR L-SHAPED COLUMNS FABRICATED USING CONCRETE-FILLED STEEL TUBES

The response of exposed column base connections for L-shaped column is investigated through finite element analysis (FEA) in this paper which is affected by complex interactions among different components. Three finite element models are constructed to simulate the response of these connections under axial and cyclic horizontal loading, which interrogate a range of variables including anchor rod strength, base plate size and thickness. The results of the simulations provide insights into internal stress distributions which have not been measured directly through experiments. The key findings indicate that thicker base plates tend to shift the stresses to the toe of the base plate, while thinner plates concentrate the stresses under the column flange. Base on the analytical results, a hysteretic model is proposed to describe the cyclic moment-rotation response of exposed column base connections. The core parameters used to define the backbone curve of the hysteretic model are calibrated through configurational details. The comparison between the simulation and the calculated values indicates that the hysteretic model is suitable to characterize the key aspects of the physical response, including pinching, recentering and flag-shaped hysteresis phenomenon. Limitations of the model are outlined.

Size and shape of plates and size of wine glasses and bottles: impact on self-serving of food and alcohol

Background The physical properties of tableware could influence selection and consumption of food and alcohol. There is considerable uncertainty, however, around the potential effects of different sizes and shapes of tableware on how much food and alcohol people self-serve. These studies aimed to estimate the impact of: 1. Plate size and shape on amount of food self-served; 2.Wine glass and bottle size on amount of wine self-poured. Methods 140 adults participated in two laboratory studies—each using randomised within-subjects factorial designs—where they self-served food (Study 1) and wine (Study 2): Study 1: 3 plate sizes (small; medium; large) × 2 plate shapes (circular; square). Study 2: 3 wine glass sizes (small; medium; large) × 2 wine bottle sizes (75 cl; 50 cl). Results Study 1: There was a main effect of plate size: less was self-served on small (76 g less, p < 0.001) and medium (41 g less, p < 0.001) plates, compared to large plates. There was no evidence for a main effect of plate shape (p = 0.46) or a size and shape interaction (p = 0.47). Study 2: There was a main effect of glass size: less was self-served in small (34 ml less, p < 0.001) and medium (17 ml less, p < 0.001) glasses, compared to large glasses. There was no evidence of a main effect of bottle size (p = 0.20) or a glass and bottle size interaction (p = 0.18). Conclusions Smaller tableware (i.e. plates and wine glasses) decreases the amount of food and wine self-served in an initial serving. Future studies are required to generate estimates on selection and consumption in real world settings when numerous servings are possible. Protocol registration information: OSF (https://osf.io/dj3c6/) and ISRCTN (10.1186/ISRCTN66774780).

Drivers of plate waste: A mini theory of action based on staff observations

Restaurants waste one fifth of the food they buy; much is left behind on people's plates (Engström &amp; Carlsson-Kanyama, 2004). Plate waste forces restaurants to buy more food than necessary, and to pay for food waste disposal; and burdens the environment, with agriculture “a dominant force behind…climate change” (Foley et al., 2011, p.337).Plate waste is under-researched in tourism (Gössling &amp; Peeters, 2015), with buffets being particularly wasteful (15 g per person per day at breakfast; Juvan, Grün, &amp; Dolnicar, 2018). Only two measures are proven to reduce plate waste at hotel buffets: smaller plates, and explaining to guests that getting seconds is better than taking too much at once (Kallbekken &amp; Sælen, 2013). Social science theories underlie these effective practical measures: the idea of plate size reduction stems from obesity theory; and inviting patrons back leverages social norms. The present study develops a new “mini-theory of action” (Rossiter, 2011, p.119) to inform the development a wider range of practical measures for plate waste reduction. Mini-theories of action formulate possible reasons for human behaviour, opening these hypothesized cause-and-effect relationships up for empirical testing in real behavioural contexts (Rossiter, 2011). Mini-theories of action, arguably, are the starting point for any new social science theory. As such, our study's contribution is primarily theoretical. Pathways to practical impact are discussed.We conducted unstructured interviews with 10 chefs and 23 waiters/waitresses (of varying gender and work experience) in three four-star rated hotels serving buffet-style meals to 300–1200 guests daily. We asked why guests leave uneaten food behind. Service staff observe and talk to guests daily, frequently checking if they are finished. In response, guests offer explanations why some food remains uneaten. Chefs design menus to minimize food waste. We identify specific drivers of plate waste, and seven overarching themes.

Analysis and design of class E-LCCL compensation circuit topology circuit topology for capacitive power transfer system

<p class="Abstract">This research introduces the analysis and design of Class E-LCCL for capacitive power transfer (CPT) system. The CPT Class-E LCCL system is able to operate at high-frequency with decreased capacitance plate size and at reduced power losses by minimising switching losses. Additionally, the design of a CPT Class-E LCCL power amplifier is less complicated, since it is usually lighter and smaller with comparative intolerance to different circuit variants; hence, enabling the possibility of miniaturising the system. In this work, the capability of the CPT Class-E LCCL CPT system powered by 24 V DC supply voltage while operating at 1 MHz was analysed via experimental works and extensive simulation. Lastly, a CPT Class-E LCCL system prototype was built, generating 10 W output power via a 0.1 cm air gap at a near-perfect efficiency level of 96.68%. These findings could be beneficial for household apparatus, medical implants, and charging consumer electronics.</p>

Food Choice and Waste in University Dining Commons—A Menus of Change University Research Collaborative Study

The purpose of this multi-campus research was to investigate the relationships of food type and personal factors with food choice, consumption, and waste behaviors of college students at all-you-care-to-eat dining facilities. The amount of food taken and wasted was indirectly measured in units relative to the plate size using before and after photos taken by the diners themselves. Animal protein and mixed dishes (e.g., stir fry, sandwich) took up more of diners’ plate space and these items were correlated to both greater hedonic appeal as well as a higher likelihood of the item being pre-plated. Greater confidence in liking an item before choosing it was correlated to a larger portion being taken. Finally, increased satisfaction with the meal and frequency of visiting the dining commons was correlated to less food waste. Understanding these potential food choice drivers can help dining facilities better target healthier meals to diners while reducing food waste.

Development and Performance Evaluation of a Bevameter for Measuring Soil Strength

The driving performance of an off-road vehicle is closely related to soil strength. A bevameter is used to measure the soil strength, and it usually consists of two independent devices: a pressure–sinkage test device and a shear test device. However, its development and measurement processes have not been standardized; thus, researchers apply it in various fields according to their own discretion. In this study, a new bevameter was developed, and experiments were conducted to clarify the factors that affect the measurement performance of the bevameter. The pressure–sinkage test device was tested with circular plates of different sizes, and the results confirmed that the pressure–sinkage parameters decreased with the plate size. For the shear-test device, normal pressure was applied using a dead load to prevent normal-pressure variation due to displacement and speed. In addition, a spline was installed on top of the shaft connected to the shear ring to measure slip sinkage during the shear test. The results showed that the slip sinkage increased in proportion to the normal pressure and slip displacement, but the increase gradually decreased and converged to a certain point.