Impact Coefficient Analysis of Curved Box Girder Bridge Based on Vehicle-Bridge Coupling

In the current vehicle-bridge dynamics research studies, displacement impact coefficients are often used to replace the moment and shear force impact coefficients, and the vehicle model is also simplified as a moving-load model without considering the contribution of vehicle stiffness and damping to the system in some concerned research studies, which cannot really reflect the mechanical behavior of the structures under vehicle dynamic loads. This paper presents a vehicle-bridge coupling model for the prediction of dynamic responses and impact coefficient of the long-span curved bending beam bridge. The element stiffness matrix and mass matrix of a curved box girder bridge with 9 freedom degrees are directly deduced based on the principle of virtual work and dynamic finite element theory. The vibration equations of vehicle-bridge coupling are established by introducing vehicle mode with 7 freedom degrees. The Newmark-β method is adopted to solve vibration response of the system under vehicle dynamic loads, and the influences of flatness of bridge surface, vehicle speed, load weight, and primary beam stiffness on the impact coefficient are comprehensively discussed. The results indicate that the impact coefficient presents a nonlinear increment as the flatness of bridge surface changes from good to terrible. The vehicle-bridge coupling system resonates when the vehicle speeds reach 60 km/h and 100 km/h. The moment design value will maximally increase by 2.89%, and the shear force design value will maximally decrease by 34.9% when replacing moment and shear force impact coefficients with the displacement impact coefficient for the section internal force design. The load weight has a little influence on the impact coefficient; the displacement and moment impact coefficients are decreased with an increase in primary beam stiffness, while the shear force impact coefficient is increased with an increase in primary beam stiffness. The theoretical results presented in this paper agree well with the ANSYS results.

Yang Liuzhuang express drone application and development study

This paper presents a feasibility study on the application of delivery drones in Yang Liu Zhuang. In order to make the cost calculation convincing, the article realistically simulates the delivery scenario of Yang Liu Zhuang during the epidemic, and then analyzes its transportation cost in depth, and finally concludes that using drones to partially replace traditional delivery in Yang Liu Zhuang can save costs and improve logistics efficiency. However, at present, the delivery by express drones is mainly limited by their own load weight, and they cannot deliver medium and large goods.

Research into the Impacts of Driving Cycles and Load Weight on the Operation of a Light Commercial Electric Vehicle

The European Parliament has adopted Directive 2019/1161 on the promotion of environmentally friendly and energy-efficient road transport vehicles, which also defines the obligations and forms of support for the procurement of environmentally friendly vehicles in urban logistics. The increase in the number of shipments delivered within e-commerce, which is also the result of the COVID-19 pandemic, requires a transition to a sustainable logistics system. New research questions are being raised in the preparation of new projects for the introduction of small electric commercial vehicles in particular. One of the main research questions about deployment itself is whether light commercial electric vehicles are able to fully replace conventionally powered vehicles. What operating conditions are optimal for the operation of them? How does load weight affect the energy efficiency of operating a light commercial electric vehicle? The authors decided to carry out research into the impacts of weight and the nature of a driving cycle under laboratory conditions to eliminate all external factors that could distort individual measurements and their results. In order to simulate driving cycles, an urban driving cycle was designed on the basis of the course of speed, acceleration, deceleration and slope conditions of roads in the selected regional city of Žilina (Slovakia). In the case of the operation of an electrically powered light commercial vehicle, the impact of load weight on the range of the vehicle is low, and is below the level of the theoretical maximum range of the vehicle in urban logistics applications. The operation of electrically powered vehicles in hilly terrains with relatively longer gradients and steeper slopes increases electricity consumption and, thereby, reduces their range.

Performa Motor Induksi Satu Phasa Sebagai Penggerak Mesin Pengering

Utilization of an induction motor as a driving force for an oil drying machine because of its strong construction and easy maintenance. The dryer is designed to use a tube made of aluminum with an iron frame equipped with a dimmer as a voltage regulator and a timer for setting the drying time. The engine performance test was carried out with a voltage variation of 80-100 Volts with a time of 30-240 seconds with a constant load weight. Based on the research, the performance of the dryer was obtained, at a voltage of 90-100 Volts, the engine speed was stable at 2500 rpm in a drying time of 90-120 seconds. The decrease in load in the drying process can increase the rotation of the motor, otherwise the motor torque will be smaller with the increase in motor rotation and the length of the drying process.

6 Does Bedding Influence Lying Behaviour of Cattle Unloaded for Rest During Long-distance Transportation?

In Canada, cattle must be unloaded, fed, watered, and rested after 36 h of transport; however, little is known about what constitutes appropriate rest station conditions. The objective of this study was to determine the relationship between providing straw bedding (14-cm deep) and trip, load, and commercial rest station characteristics, on lying behaviour. Truckloads (n = 13) were split; half the animals were assigned to either bedded (n = 452 cattle) or non-bedded (n = 470 cattle) pens. Trip characteristics [time in motion (TIM), duration of stops en route (DUR_STOPS)], load characteristics (sex: heifers, steers, both; and load weight), and rest station characteristics [ambient temperature at unloading; rest pen space allowance (k_PEN); time in resting pen (TIP)] were recorded. Once unloaded we counted the number of cattle lying/pen, every 10 min for 8 h. A mixed logistic regression model with random intercepts for load and truck compartment was fitted to examine associations between the proportion of animals lying and the independent variables (i.e., treatment, trip, load, and rest station characteristics). Odds of lying increased with load weight (i.e., cattle weight class, P = 0.02) and with DUR_STOPS (P < 0.03). There was an interaction (P < 0.01) between treatment and TIM: as TIM increased, the odds of observing cattle lying showed a notable increase for cattle rested in bedded pens, whereas for those rested in non-bedded pens, the odds showed little change as TIM increased. An interaction (P < 0.01) was also found between treatment and TIP: early in the observation period, the odds of cattle lying were greater in bedded pens. Both groups showed an increase in the probability of lying over time, plateauing at similar levels, near the end of the 8-h observation period. In conclusion, providing straw bedding at rest stations influenced cattle’s motivation to lie, particularly following longer transport durations.

Uso de carretilla de acero en transporte de carga para prevención de trastornos musculo-esqueléticos en los trabajadores de despacho de la empresa Ecovasti S.A.

Introduction. Manual lifting and carrying of loads that are equal to or greater than 25 kg are considered high ergonomic risk for causing musculoskeletal disorders in any activity where there is no load sharing or mechanical assistance. Objective. This research applies the use of a steel mask as a mechanical aid to attenuate musculoskeletal disorders in the workers of the company Ecovasti S.A. who lift and move the jars of alcoholic beverages in the delivery of the product to the customers. Methodology. A preliminary analysis of the lifting and moving of loads in the manual dispatch of alcoholic beverage jars was made using Snook and Ciriello tables to find the maximum acceptable weight and the level of ergonomic risk, then the key indicators of pull and push method (KIM PP) was applied to demonstrate the ergonomic improvement by implementing the help of a mobile steel forklift. Results. The preliminary study with the Snook and Ciriello tables indicates a maximum load handling weight for lowering, lifting, transporting and dragging: 11.9 kg; 7.79 kg; 16.43 kg and 25.67 kg respectively, considering male gender, with a protection percentage of 90%, maximum distance traveled of 8 m, load weight of 23 kg per jug of alcoholic beverage, average transfer height of 0.8 m, with a frequency of 15 transfers per hour. The result of the application of the ergonomic improvement with the use of the key indicators of pull and push method (KIM PP) was a value of 1, which corresponds to a low ergonomic risk with a low probability of physical overload. Conclusion. The result of the application of a steel trolley for the manual transport of alcoholic beverage jugs in the dispensing to customers attenuates the level of ergonomic risk to low risk values and could help prevent musculoskeletal disorders.

Local Porters in Nepal: Acute Mountain Sickness and Load Weight of Cargo Carrying

Local porters who haul burdens for trekkers are understudied and underappreciated for the labour they do in Nepal. Their susceptibility to Acute Mountain Sickness (AMS) along with the weight of the loads they haul and carry in return for meagres payment, contribute to the difficulties of their very austere and under-resourced employment. They are frequently underpaid for their efforts. Acknowledgement by government organizations and trekking business owners could make their employment more viable by giving them a higher wage in spite of their occupation struggles. Data was gathered from 31 porters completing instruction at a Nepali Porters’ training establishment, based in Kathmandu, Nepal. The research used semi-structured in-depth interviews. Participants participated in a 45-60-minute interview, which was recorded at the field site. All the interviews were documented and then transcribed into English by a bilingual Nepali PhD student. The data was coded using a hierarchical, thematic coding structure approach. Findings showed that porters knew about and had experienced AMS, and that their work of carrying heavy cargoes for trekkers and trekking companies were often not compliant with prescribed kilogram load limits.

Effects of Heating Temperature and Load Weight on Rheological Properties of Waste Plastic Cup

Analysis of heating temperature and load weight to the rheological properties of waste plastic cups is very important to gain fundamental understanding of the structure, characteristics, and processability of the material. The samples were tested using melt flow indexer. The heating temperature investigated were 180°C, 190°C, 200°C, 210°C, 220°C and 230°C, and the weight load were 1,875 g, 2,160 g, 2,835 g, 3,035 g and 3,450 g. The results obtained showed that the rheological properties of products such as melt flow index, shear stress and shear rate increased and the viscosity decreased with the increasing of heating temperature and load weight. For higher heating temperatures, the melt flow index, shear stress and shear rate of waste plastic cup increased significantly with the increasing load weight whereas the viscosity of waste plastic cup did not decrease significantly with the increasing load weight.

Soldier Load Carriage, Injuries, Rehabilitation and Physical Conditioning: An International Approach

Soldiers are often required to carry heavy loads that can exceed 45 kg. The physiological costs and biomechanical responses to these loads, whilst varying with the contexts in which they are carried, have led to soldier injuries. These injuries can range from musculoskeletal injuries (e.g., joint/ligamentous injuries and stress fractures) to neurological injuries (e.g., paresthesias), and impact on both the soldier and the army in which they serve. Following treatment to facilitate initial recovery from injuries, soldiers must be progressively reconditioned for load carriage. Optimal conditioning and reconditioning practices include load carriage sessions with a frequency of one session every 10–14 days in conjunction with a program of both resistance and aerobic training. Speed of march and grade and type of terrain covered are factors that can be adjusted to manipulate load carriage intensity, limiting the need to adjust load weight alone. Factors external to the load carriage program, such as other military duties, can also impart physical loading and must be considered as part of any load carriage conditioning/reconditioning program.