E-bikes among older adults: benefits,disadvantages, usage and crash characteristics

Transportation - The promotion of sustainable and healthy mobility among older adults (≥?65 years) is an important challenge. E-bikes may be part of the solution, but research...     

A Novel Approach to Vehicle Dynamics using the Theory of a Cosserat Point and its Application to Collision Analyses of Platooning Vehicles

A fully three-dimensional, computationally inexpensive vehicular model is presented. In contrast to traditional rigid body models, the vehicle's sprung mass is modeled as a (nonlinearly) deformable body. The formulation of the equations of motion is based on a continuum theory known as the theory of a Cosserat point. These equations largely preserve the relative simplicity of rigid body dynamics but incorporate deformable features. The ease of computer implementation permits the simultaneous simulation of vehicle and collision dynamics of multiple vehicles and highway objects. In this paper, the theory of a Cosserat point is summarized and its general application to vehicle and collision dynamics is illustrated. A three-dimensional collision algorithm is discussed with emphasis on small closing velocities (negligible residual crush, elastic rebound). The novel model is compared to standard procedures.     

高档汽车却用便携式导航仪？

坐朋友的车去旅行，发现在其价值百万元的车里用的是一部便携导航仪，忍不住问他：“你车里明明有原装的车载导航，为什么要用一部便宜的便携导航产品呢？”他给我的答复是：原装的导航地图还不如便携机的地图。     

Seasonal variability of the Black Sea chlorophyll-a concentration

The optimal spectral decomposition (OSD) method is used to reconstruct seasonal variability of the Black Sea horizontally averaged chlorophyll-a concentration from data collected during the NATO SfP-971818 Black Sea Project in 1980–1995. During the reconstruction, quality control is conducted to reduce errors caused by measurement accuracy, sampling strategy, and irregular data distribution in space and time. A bi-modal structure with winter/spring (February–March) and fall (September–October) blooms is uniquely detected and accurately documented. The chlorophyll-a enriched zone rises to 15 m depth in winter and June, and deepens to 40 m in April and 35 m in August. The June rise of the chlorophyll-a enriched zone is accompanying by near-continuous reduction of upper layer maximum chlorophyll-a concentration.     

Management and labour in shipping: A role for co-operatives

The employment and management policies of the shipping industry are in legal and administrative confusion. The shipping industry is struggling with an unworkable global governance based on flag state sovereignty and a sanctionless international regulatory regime. Seafarers suffer most from this state of affairs, but so do the shipping industry’s public image. Few co-operatives of maritime workers exist in national or international shipping. A new employment theory is long overdue. Human centred management policies can only attain their full potential through co-operative or mutual associations. This paper describes the application of enlightened and socially conscious management principles to the shipping industry. Seafarers’ co-operatives are the future organisational building blocks of the shipping industry. Co-operatives can rescue maritime workers from developing countries from exploitation and the debilitating effects of casual labour by providing “all in one” seagoing and shore based professional careers. Seafarers’ co-operatives can solve the shipping industry’s maritime training and education problems. The seven universal principles of co-operative management will guide shipping management in setting human centred objectives that command respect of those who come in contact with the shipping industry.     

马不扬鞭自奋蹄 Mazda CX-9

马自达在北美发布了一款7人座的SUV——2007 CX-9，CX-9是针对北美市场开发设计的，它提供了独特而充满活力的设计以及高档的内饰和宽敞的空间。     

The Northwest Passage: A simulation

We model shipping through the Northwest Passage in northern Canada in order to see if reported recent ice thinning has made this route economic relative to the Panama Canal. Container shipping between Yokohama to New York and St. Johns, Newfoundland is simulated by VSLAM for the two routes using bluewater ships for the Panama Canal and identically sized Canadian Arctic Class 3 (CAC3) ships for the Northwest Passage. Each route is broken into a series of logical legs, and environmental conditions and wait times are assigned. Ice conditions are modeled from historical records. Average speed through the Northwest Passage shows little seasonal variation. Round trips per year are higher through the Northwest Passage. The required freight rate (RFR) to recover all costs including capital recovery is calculated. RFR is slightly lower for the St. Johns to Yokohama transit using the Northwest Passage, and higher for the New York to Yokohama route, as compared to the Panama Canal. Possible future thinning of Arctic ice would further improve the economics of the Northwest Passage.