Solar access of residential rooftops in four California cities

Shadows cast by trees and buildings can limit the solar access of rooftop solar-energy systems, including photovoltaic panels and thermal collectors. This study characterizes residential rooftop shading in Sacramento, San Jose, Los Angeles and San Diego, CA. Our analysis can be used to better estimate power production and/or thermal collection by rooftop solar-energy equipment. It can also be considered when designing programs to plant shade trees.High-resolution orthophotos and LiDAR (Light Detection And Ranging) measurements of surface height were used to create a digital elevation model of all trees and buildings in a well-treed 2.5–4 km² residential neighborhood. On-hour shading of roofing planes (the flat elements of roofs) was computed geometrically from the digital elevation model. Values in future years were determined by repeating these calculations after simulating tree growth. Parcel boundaries were used to determine the extent to which roofing planes were shaded by trees and buildings in neighboring parcels.For the subset of S + SW + W-facing planes on which solar equipment is commonly installed for maximum solar access, absolute light loss in spring, summer and fall peaked about 2 to 4 h after sunrise and about 2 to 4 h before sunset. The fraction of annual insolation lost to shading increased from 0.07–0.08 in the year of surface-height measurement to 0.11–0.14 after 30 years of tree growth. Only about 10% of this loss resulted from shading by trees and buildings in neighboring parcels.     

Pharmacokinetic-pharmacodynamic analysis of changrolin in dogs with arrhythmia

The pharmacokinetics and pharmacodynamics of changrolin (CRL) were studied in 7 dogs with arrhythmia induced by coronary artery ligature. The ECG and the percentage of reduction ratio of ventricular premature were used to evaluate the effect of CRL, and an HPLC method was used to determine the serum drug concentration. A pharmacokinetic program was used to fit concentration-time (C-T) data and a combined pharmacokinetic-pharmacodynamic model was used to analyze effect-time (E-T) data in individual dogs. After infusion with CRL 83.33 micrograms.kg-1.min-1 for 60 min, it was found that K10, T1/2, Vd, Cl and Ce were 0.0087 min-1, 78.03 min, 40.55 ml.kg-1, 0.42 ml.kg-1.min-1, and 2.01 micrograms.ml-1, respectively.     

Modeling the Growth of Transportation Networks: A Comprehensive Review

This paper reviews the progress that has been made over the last half-century in modeling and analyzing the growth of transportation networks. An overview of studies has been provided following five main streams: network growth in transport geography; traffic flow, transportation planning, and network growth; statistical analyses of network growth; economics of network growth; and network science. In recognition of the vast advances through decades in terms of exploring underlying growth mechanisms and developing effective network growth models, the authors also point out the challenges that are faced to model the complex process of transport development.     

在第三代程序设计语言（3GL）中引入面向对象的思想

面向对象技术，源于对现实世界中自然结构的认识，充分体现了概括，分类和抽象的思想。本文就如何在３ＧＬ软件开发中引入ＯＯ的思想，提出了函数实体和消息变量的概念，分别对应于Ｏ技术中的对象和消息的概念，并结合实例，分析了在３ＧＬ软件开发中引入ＯＯ思想的几个要点。     

Rinse-added fabric softener technology at the close of the twentieth century

This paper reviews rinse-added liquid fabric softener products including current and emerging technologies related to composition, raw materials, and manufacturing processes. An introductory overview of the historical drivers, market trends, advantages and disadvantages, and consumer habits and practices that affect these products is also included.     

Potential benefits of cool roofs on commercial buildings: conserving energy, saving money, and reducing emission of greenhouse gases and air pollutants

Cool roofs—roofs that stay cool in the sun by minimizing solar absorption and maximizing thermal emission—lessen the flow of heat from the roof into the building, reducing the need for space cooling energy in conditioned buildings. Cool roofs may also increase the need for heating energy in cold climates. For a commercial building, the decrease in annual cooling load is typically much greater than the increase in annual heating load. This study combines building energy simulations, local energy prices, local electricity emission factors, and local estimates of building density to characterize local, state average, and national average cooling energy savings, heating energy penalties, energy cost savings, and emission reductions per unit conditioned roof area. The annual heating and cooling energy uses of four commercial building prototypes—new office (1980+), old office (pre-1980), new retail (1980+), and old retail (pre-1980)—were simulated in 236 US cities. Substituting a weathered cool white roof (solar reflectance 0.55) for a weathered conventional gray roof (solar reflectance 0.20) yielded annually a cooling energy saving per unit conditioned roof area ranging from 3.30 kWh/m² in Alaska to 7.69 kWh/m² in Arizona (5.02 kWh/m² nationwide); a heating energy penalty ranging from 0.003 therm/m² in Hawaii to 0.14 therm/m² in Wyoming (0.065 therm/m² nationwide); and an energy cost saving ranging from 0.126/m < sup > 2 < /sup > in West Virginia to0.126/m² in West Virginia to 1.14/m² in Arizona ($0.356/m² nationwide). It also offered annually a CO₂ reduction ranging from 1.07 kg/m² in Alaska to 4.97 kg/m² in Hawaii (3.02 kg/m² nationwide); an NO_x reduction ranging from 1.70 g/m² in New York to 11.7 g/m² in Hawaii (4.81 g/m² nationwide); an SO₂ reduction ranging from 1.79 g/m² in California to 26.1 g/m² in Alabama (12.4 g/m² nationwide); and an Hg reduction ranging from 1.08 μg/m² in Alaska to 105 μg/m² in Alabama (61.2 μg/m² nationwide). Retrofitting 80% of the 2.58 billion square meters of commercial building conditioned roof area in the USA would yield an annual cooling energy saving of 10.4 TWh; an annual heating energy penalty of 133 million therms; and an annual energy cost saving of $0.356/m² nationwide). It also offered annually a CO₂ reduction ranging from 1.07 kg/m² in Alaska to 4.97 kg/m² in Hawaii (3.02 kg/m² nationwide); an NO_x reduction ranging from 1.70 g/m² in New York to 11.7 g/m² in Hawaii (4.81 g/m² nationwide); an SO₂ reduction ranging from 1.79 g/m² in California to 26.1 g/m² in Alabama (12.4 g/m² nationwide); and an Hg reduction ranging from 1.08 μg/m² in Alaska to 105 μg/m² in Alabama (61.2 μg/m² nationwide). Retrofitting 80% of the 2.58 billion square meters of commercial building conditioned roof area in the USA would yield an annual cooling energy saving of 10.4 TWh; an annual heating energy penalty of 133 million therms; and an annual energy cost saving of 735 million. It would also offer an annual CO₂ reduction of 6.23 Mt, offsetting the annual CO₂ emissions of 1.20 million typical cars or 25.4 typical peak power plants; an annual NO_x reduction of 9.93 kt, offsetting the annual NO_x emissions of 0.57 million cars or 65.7 peak power plants; an annual SO₂ reduction of 25.6 kt, offsetting the annual SO₂ emissions of 815 peak power plants; and an annual Hg reduction of 126 kg.