Intrastate differences in residential water demand

To date, the results of studies which attempted to estimate residential water demand models have varied, but the source of these variations is not evident because the studies have applied different methodologies and data bases to different regions. The purpose of this paper is to develop models of residential water demand for watershed regions and test the null hypothesis that a single model is adequate to explain variations for all of the individual regions. Primary data collected from questionnaires and utility company records is used in a regression analysis to estimate a generalized water demand model for the state as well as one for each of the subregions. The null hypothesis is rejected which indicates that there are other factors which influence the demand for water and the use of a single model could result in biased estimates.     

道路维修工作

<正>基础设施的维护,与新建道路一样重要——最极端且具有悲剧性的例子可用美国明尼阿波列斯州际公路W35桥梁的坍塌,Richard High对一些国家正在进行的基础设施维护工作作了报道。     

Modification of Polycaproamide Composites Based on 1H,1H,13H-rihydroperfluorotridecan-1-ol and Montmorillonite

Fibre Chemistry - Modification of polycaproamide by 1H,1H,13H-trihydroperfluorotridecan-1-ol immobilized on montmorillonite produced an F-containing polymer composite. The structure of the...     

Improving the Quality of Cellulose for Use in Disposable Sanitary and Hygiene Products

Fibre Chemistry - Under modern conditions the creation of materials for sanitary hygiene and medical products based on cellulose is of paramount importance. Development and improvement in this area...     

Investigation of 12 – 15 Kev Electron Transmission Through Tapered Glass Capillaries

Glass and Ceramics - The results of experimental studies of the transmission of 12 and 15 keV electron beams through tapered glass macro-capillaries are presented. Measurements showed that there is...     

Mechanical and Tribological Properties of Ca/P-Doped Titanium Dioxide Layer Produced by Plasma Electrolytic Oxidation: Effects of Applied Voltage and Heat Treatment

Plasma electrolytic oxidation (PEO) is a technique that produces a hard oxide layer on the titanium surface where its properties can be tailored by changing the process parameters or by a posterior heat treatment (HT). In this work, a TiO₂ layer with different crystallinity was produced by PEO with different applied voltages (250 to 400 V) and post-HT at 600°C. Our aim was to evaluate the influence of the PEO voltage and HT on the mechanical and tribological properties of anodized Ti. There is an increase in pore size, oxide thickness, and Ca/P ratio for the oxide layer with the applied voltage during the PEO process. X-ray diffraction (XRD) results indicated an increase in the crystalline rutile phase in the oxide layer with voltage and HT. Nanoindentation shows an increase in the oxide hardness and elastic modulus with increased voltage and HT, leading to an improvement in the wear resistance.     

Machining of NiTi-shape memory alloys-A review

The emerging trends in the development of advanced smart materials with better unique properties under different environments for a particular application fascinate the researchers and industrialists. Nickel-Titanium based shape memory alloys are exotic materials due to their unique properties such as SME, SE, high damping characteristics, high corrosion and wear resistance and biocompatibility. This article presents an overview of machining processes that can be used to machine the NiTi and its surface induced characteristics such as microhardness, surface roughness, topography, induced layer, residual stress, fatigue and phase transformation. The surface integrity characteristics are discussed for machining of NiTi-SMAs under the category of traditional, non-traditional and micro-machining with the effect of input parameters such as cutting speed, feed, depth of cut, type of lubricant and type of coating material on cutting tool. The conventional machining of NiTi alloys are quite complicated due to high toughness, severe strain hardening, fatigue hardening and distinctive property of NiTi-SMAs such as pseudoelastic and shape memory effect. From this study, non-traditional process is significantly used to machine the NiTi-SMAs due to its better results on surface integrity characteristics. Consequently, future trends are also identified for machining the NiTi-SMAs and to improve the surface integrity characteristics.     

Exact solutions to differential-difference heat and mass transfer equations with a finite relaxation time

Certain exact solutions to the linear differential-difference heat and mass transfer equations with a finite relaxation time are specified. The exact solution to the one-dimensional Stokes problem with the periodic boundary condition when a first-order volume chemical reaction occurs is given. A wide class of exact solutions to the nonlinear differential-difference heat-conduction equation with the following source is described: $$\Theta _t = div[f(T)\nabla T] + g(\Theta ), = T(r,t + \tau ),$$ where T = T(r, t) is temperature and τ is the relaxation time. Certain more complex heat conduction models with a variable relaxation time that can depend on time and a temperature gradient are also considered.