Unit Load System Research Articles

Vibration Analysis of Uniform Flexible Beams under Large Deformation with Uniformly Continuous Mass Elements Using the Equivalent Pseudolinear System

This paper analyses vibration of uniform flexible simply supported rectangular isotropic beam under large deformation with uniformly distributed mass elements. The method of equivalent pseudolinear systems was employed. The deformation of the beam was assumed to be large and the beam was also assumed to be inextensible. The expressions for elastic and nonlinear bending moments were determined. The numerical values of horizontal displacements of the movable support, and the equivalent lengths at various depth-to-breadth (aspect) ratios were determined. The corresponding equivalent pseudolinear systems for various nonlinear bending moment diagrams at various aspect ratios were determined. Consequently the concentrated loads yielding the equivalent pseudolinear systems were converted to point masses using the gravitational acceleration; and subsequently a unit load system was applied successively and independently at each mass point. The Vereshchagin’s method was applied to determine the displacements for canonical equations of motion. Non-trivial solution of the canonical equations at each aspect ratio was sought for the desired eigenvalues. The first mode frequencies at aspect ratios, β = 1.00 and β = 1.25 are complex eigenvalues. Also the natural frequencies exhibit hard-spring type with aspect ratios; and the fundamental frequencies for all the aspect ratios are at seventh mode. Conclusively, the dynamic stability of the flexible rectangular beam of 0.25m-breadth and 15m-undeformed length is not guaranteed when the aspect ratio is less than or equal to 1.25. It is also concluded that deepness of the flexible rectangular beam loaded with uniformly distributed mass elements influences the vibratory characteristics.

Characterization of low‐acceleration, long‐duration horizontal events using a spring suspension straight delivery box truck

AbstractA field measurement study, using a combination of controlled and uncontrolled phases, examined low‐acceleration, long‐duration events occurring during over‐the‐road truck transport. A field data recorder equipped with a DC‐based triaxial accelerometer was employed for this study to capture the steady‐state nature of these event types. The field data recorder was rigidly mounted to the trailer chassis to record lateral and longitudinal events of interest. The controlled phase recorded normal and aggressive braking events and traversing a roundabout to fundamentally quantify the behaviour of the vehicle. For the controlled phase, average decelerations of 0.27 and 0.45 g were reported for normal and aggressive braking events, respectively. Lateral accelerations from traversing a roundabout were on average 0.40 g. The uncontrolled field measurement study, which evaluated the transport vehicle over 13 days, reported average longitudinal decelerations and lateral accelerations of 0.29 and 0.34 g, respectively. The rise times associated with these events were also reported. The jerk was calculated based on the rise times for the controlled and uncontrolled phases and compared to currently available test procedures. For both project phases, composite test profiles were developed based on field‐measured levels. The resulting composite test profiles can be utilized to evaluate the load stability of a unit load system travelling through this distribution channel.

Quantifying the effects of vehicle technical performance and electricity carbon intensity on greenhouse gas emissions from electric light truck: A case study of China

The concept of an electric light truck (ELT) with green environmental protection has been accepted by governments and purchasers with the promotion of Made in China (2025) and the Blue Sky Protection Campaign. However, the ELT's characteristics of low gas emissions and zero pollution should be further investigated. An electric light truck emissions index (ELTEI) is established to explore the greenhouse gas (GHG) emissions of ELT. The ELTEI considers electricity carbon intensity and vehicle technical performance that includes temperature-capacity compensation coefficient, battery attenuation coefficient, energy consumption per unit load and battery system energy density. Results of a case study in China show that sub-zero temperature leads to significant fluctuations in the temperature-capacity compensation coefficient, which can increase the GHG emissions of ELT in the northern provinces. In the southern and central provinces, ELT can replace diesel light truck to reduce GHG emissions after improving the battery attenuation coefficient by 15% when ELT is utilized for 4 years. Compared with increasing the battery weight to decrease the value of energy consumption per unit load, increasing the battery system energy density to reduce the vehicle weight can fundamentally lower GHG emissions. The reduction ratio is inversely proportional to the minimum average temperature in the first quarter by reducing the electricity carbon intensity to minimize the GHG emissions of ELT. Insights derived from this study can provide available suggestions for research on the GHG emissions of ELT.

Power unit load system modelling research based on BP neural network

A thermal power unit is a very complex non-linear multi-variable control object. It has the characteristics of strong coupling, large inertia, large delay and time-varying parameters. The traditional mathematical model is difficult to describe the non-linear characteristics among the parameters of the unit, and it is difficult to meet the control requirements of unit load, main steam pressure and so on. Based on the more advanced BP neural network modeling method, the mathematical model of the operation of 600MW thermal power unit under low, medium and high load is established by using the actual operation data on site. The method used is novel, and the simulation analysis shows that the model also has a strong engineering practice.

수산물의 기능성 재사용 포장용기 사용을 통한 물류합리화에 관한 연구

Disposable marine product packaging materials such as wooden, Styrofoam, and corrugated cardboard boxes have a very low reuse rate, thus causing the logistics costs to rise and making it difficult to establish a unit load system for marine products. Disposable packing containers to be discarded are accompanied by resource and environmental issues home and abroad. Transportation vehicles for marine products have to return empty without loading different kinds of products after delivery due to the smell and properties of marine products, thus posing as an obstacle to logistics rationalization. In an effort to overcome those limitations, this study examined the stages of transportation including "producer-wholesale market in the producing area-commission merchant-wholesale market in the consumption area-commission merchant-quasi-wholesale market-consumer" and also analyzed the utilization and distribution of disposable packaging materials currently used in the circulation of marine products including wooden, Styrofoam, and corrugated cardboard boxes. Based on the analysis results, the investigator developed a logistics rationalization model capable of promoting semi-permanent reuse and lowering empty vehicle rate on return routes as an alternative to address environmental issues caused by disposable packaging materials, which have been an obstacle to the logistics rationalization of marine products, packaging costs in the process of repeating packing and unpacking at each stage of marine products circulation, and empty vehicle rates on return routes after marine products delivery.

A Study on Introduction of Unit Load System for Frozen Food Industry - Focus On Logistics Operation of Ice Cream of A’s Company -

A Study on Introduction of Unit Load System for Frozen Food Industry - Focus On Logistics Operation of Ice Cream of A’s Company -

수요기반 물류인증을 통한 물류산업 활성화 방안

The increase of international and domestic trade according to global industrialization and economic growth has raised the national logistic cost in connection with physical distribution of articles. In order to reduce these costs and rise up national industrial competitiveness, Korea has also tried to improve the efficiency of logistics with various methods as advanced countries did. Especially, Korea government has decided standard dimension of pallets with T11 (1100×1100 mm) on the basis of unit load system in early 2000s, and certification program for logistics equipments has been operated to keep up the compatibility for the equipments and packaging with modulation of T11. Consequently, this certification program has contributed to extend standardization for logistics and to grow up 3 party logistics, but compared with advanced countries, the rate of national logistics cost to GDP (gross domestic product) still shows about 3% gap as demands for certification have been decreased in the recent. In this study, therefore, we proposed the development of logistics certification system based on social needs as a policy device to activate logistic industry as well as improve the efficiency of national logistics after we had analyzed all of certification programs for logistics being run in Korea. Namely, the first is the development of certification project for Northeast Asia's logistics corresponding to necessity for applying returnable transport system according to increasing the amount of trade between Northeast Asia's countries. The second is the development of certification project for safe transportation of packaging corresponding to costumer's needs for safe transit according to the growth of electronic commerce and the increase of global distribution.

Analysis of Impacting Factors on Construct of the Unit Load system

Analysis of Impacting Factors on Construct of the Unit Load system

Diffuse pollutant unit loads of various transportation landuses

ABSTRACT A four-year monitoring study was conducted to determine the diffuse pollutant unit loads for the six representative transportation landuses (i.e., highway, parking lot, bridge, service area and toll gate) in urban areas in Korea. Pollutant event mean concentrations (EMCs) were calculated from 123 storm events at eleven sites and the average annual rainfall and runoff coefficients were determined to estimate the unit loads using the National Institute of Environmental Research (NIER) method. Apparent differences in the unit load values existed among landuses as explained by the high variability of EMCs for different rainfall events. The study has found that runoff from bridges and highways contained the highest loadings of TSS and COD while service areas are the primary sources of nutrients and metals. The results of this study could be used by the Ministry of Environment (MOE) to separate the unit loads of transportation landuses from the urban area category in the current unit load system. The v...

Development of Standard for Roll Container to build up a Unit Load System in Retail Industry

Development of Standard for Roll Container to build up a Unit Load System in Retail Industry

Consideration of Trade Situation in Rational Pallet Size for Unit Load System

Consideration of Trade Situation in Rational Pallet Size for Unit Load System

종이 앵글 포장재의 재료역학적 특성과 유한요소해석

Paper angle, environment friendly packaging material, has been mainly used as an edge protector, But, in the future, paper angle will be applied to package design of heavy product such as strength reinforcement or unit load system (ULS). Therefore. understanding of buckling behavior fur angle itself, compression strength and quality standard are required. The objectives of this study were to characterize the buckling behavior by theoretical and finite element analysis, and to develop compression strength model by compression test for symetric and asymetric paper angle. Based on the result of theoretical and finite element analysis, as applied load level was bigger and/or the length of angle was longer, incresing rate of buckling of asymmetric paper angle was higher than that of symmetric paper angle. Decreasing rate of minimum principal moment of inertia significantly increased as the extent of asymmetric angle increased, and buckling orientation of angle was open- direction near the small web. Incresing rate of maximum compression strength (MCS) for thickness of angle decreased as the web size increased in symmetric angle. MCS of asymmetric angle of 43<TEX>${\times}$</TEX>57 and 33<TEX>${\times}$</TEX>67 decreased <TEX>$15{\~}18\%$</TEX> and <TEX>$65{\~}78\%$</TEX>, and change of buckling increased <TEX>$12{\~}13\%$</TEX> and <TEX>$62{\~}66\%$</TEX>, respectively.