Institutional, geographic, and facility factors affecting differences in prices for wastewater services

The provision of wastewater services is an important infrastructure service that affects social welfare. It improves the quality of community life by promoting sanitary conditions and minimizing the negative impact of wastewater on ecosystems. The price for this important public service, however, varies considerably across regions and localities. In this paper, we examine the physical factors and institutional characteristics that affect wastewater service prices across regions and localities. Our major concerns are the following: (1) institutional arrangements and characteristics of a wastewater utility, (2) government regulations, (3) supply factors and characteristics, and (4) natural environments and local characteristics. To analyze the price differences, we employ the demand and price equations for wastewater services using a simultaneous equations framework. For empirical estimation, we utilize a seemingly unrelated regression (SUR) method to account for the correlations between the residuals in the four price equations for wastewater services. Our empirical results are that the institutional arrangement of services, including monthly charges (versus bi-monthly or quarterly charges), provision of other infrastructure services in addition to wastewater services, and long-term debt, explain much of the price difference. In addition, the wastewater prices are influenced by state environmental regulations as well as supply factors, such as the number of wastewater treatment plants and infiltration and inflow into the sewer system. Interestingly, local geographic and meteorologic factors that were hypothesized to affect the selection of treatment processes were not found to be associated with price. These findings suggest ways wastewater services might be offered at lower prices for users.     

Sludge settleability detection using automated SV30 measurement and comparisons of feature extraction methods

The need for automation and measurement technologies to detect the process state has been a driving force in the development of various measurements at wastewater treatment plants. While the number of applications of automation & measurement technologies to the field is increasing, there have only been a few cases where they have been applied to the area of sludge settling. It is not easy to develop an automated operation support system for the detection of sludge settleability due to its site-specific characteristics. To automate the human operator’s daily test and diagnosis work on sludge settling, an on-line SV30 measurement was developed and an automated detection algorithm on settleability was developed that imitated heuristics to detect settleability faults. The automated SV30 measurement is based on automatic pumping with a predefined schedule, the image capture of the settling test with a digital camera, and an analysis of the images to detect the settled sludge height. To detect settleability faults such as deflocculation and bulking from these images, two feature extraction methods were used and their performance was evaluated.     

Alkylation of mixed micro‐ and nanocellulose to improve dispersion in polylactide

Nanocellulose tends to be aggregated due to the hydrogen bonding between three of the hydroxyl groups in each repeat unit, resulting in poor dispersion in non‐polar polymer matrices. In this research, to improve the dispersion of cellulose particles in a polymer matrix, a long hydrophobic alkyl chain was substituted for hydrogen in the hydroxyl group of cellulose via a bimolecular nucleophilic substitution (S_N2) reaction with alkyl bromide. Octyl (? C₈H₁₇) and dodecyl (? C₁₂H₂₅) groups were applied in this reaction, which is faster and simpler than other substitution reactions. The chemical structures of octyl and dodecyl ether cellulose were identified using Fourier transform infrared and NMR analyses. The contact angle with water and methylene iodide was measured to calculate the surface energy of alkyl nanocellulose. The surface energy was decreased by the substituted alkyl chain. The thermal properties, morphology and crystal structure of octyl and dodecyl ether cellulose were also investigated to determine the possibility of use as a reinforcement. Furthermore, polylactide/alkyl ether cellulose composites were prepared to make certain of sufficient dispersion of the alkyl ether cellulose in the polylactide matrix. The thermal and mechanical properties of the polylactide composite films were investigated. The optical transmittance of the polylactide composites was measured to confirm the relative dispersity. © 2014 Society of Chemical Industry     

含圆柱形非金属夹杂构件脉冲放电的热应力场

根据脉冲放电对含圆柱形非金属夹杂构件所引起的温度场,将其分解为轴对称温度场和非轴对称温度场两部分,采用热弹性位移势及叠加原理,在给定的边界条件下,分别求解两类温度场所引起的热应力场。以16Mn构件强化为例求解夹杂边界处热应力分布发现,在该区域,无论径向、周向应力均为压应力,而且远超出材料的屈服强度;在温度和应力耦合作用下,将极大影响夹杂附近的组织性能及应力状态。进一步研究沿径向路径的热应力变化发现,脉冲放电引起的热应力仅对含夹杂区域的组织性能及应力状态影响较大,而对无夹杂区域并没有太大影响,因此,该技术可应用于在线构件的强化。     

Effects of processing parameters on creep behavior of 316L stainless steel produced using selective laser melting

Journal of Mechanical Science and Technology - The selective laser melting (SLM) method is being increasingly applied in the aerospace and power industries for the production of high temperature...     

Aging of polyamide 11. Part 1: Evaluating degradation by thermal,mechanical, and viscometric analysis

Hydrolytic degradation at elevated temperatures is a key reason for failure in offshore flexible risers. In this article, the aging of polyamide 11 in deoxygenated water at 90°C and 120°C was studied. Tensile and dynamic mechanical thermal analysis tests were performed to measure changes in mechanical properties. Viscometry, gravimetric measurements, differential scanning calorimetry, and thermogravimetric analysis were used to link these properties with morphological changes. General trends are increased stiffness, tensile strength, and glass transition temperature as well as decreased glassy state damping efficiency with increased aging times. Changes can be initially ascribed to plasticizer depletion and then to interplay between molecular weight decrease and crystallinity increase. Viscosity at hydrolysis equilibrium indicates that brittle failure typically involves oxidation or UV exposure. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41971.     

Aging of polyamide 11. Part 3: Multiscale model predicting the mechanical properties after hydrolytic degradation

A holistic general multiscale model of polymer degradation has been applied to predict the mechanical properties of polyamide 11 after the hydrolytic ageing. Results for elastic modulus, tensile strength, and embrittlement threshold have been compared with experimental aging in deoxygenated water at 120°C. For all studied properties the modeled trend is close to the experimental test results confirming hydrolysis induced chain scission and chemicrystalization as the two main mechanisms of property change. This suggests that the multiscale modeling methodology can provide a valuable alternative to accelerated aging tests. The model also indicated that the crystalline phase does play a role in the plastic deformation. Moreover, the mechanical equilibrium between effects of macromolecule degradation and an increased degree of crystallinity has been described. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42792.     

Effect of Wnt3a on Keratinocytes Utilizing in Vitro and Bioinformatics Analysis

Wingless-type (Wnt) signaling proteins participate in various cell developmental processes. A suppressive role of Wnt5a on keratinocyte growth has already been observed. However, the role of other Wnt proteins in proliferation and differentiation of keratinocytes remains unknown. Here, we investigated the effects of the Wnt ligand, Wnt3a, on proliferation and differentiation of keratinocytes. Keratinocytes from normal human skin were cultured and treated with recombinant Wnt3a alone or in combination with the inflammatory cytokine, tumor necrosis factor α (TNFα). Furthermore, using bioinformatics, we analyzed the biochemical parameters, molecular evolution, and protein–protein interaction network for the Wnt family. Application of recombinant Wnt3a showed an anti-proliferative effect on keratinocytes in a dose-dependent manner. After treatment with TNFα, Wnt3a still demonstrated an anti-proliferative effect on human keratinocytes. Exogenous treatment of Wnt3a was unable to alter mRNA expression of differentiation markers of keratinocytes, whereas an altered expression was observed in TNFα-stimulated keratinocytes. In silico phylogenetic, biochemical, and protein–protein interaction analysis showed several close relationships among the family members of the Wnt family. Moreover, a close phylogenetic and biochemical similarity was observed between Wnt3a and Wnt5a. Finally, we proposed a hypothetical mechanism to illustrate how the Wnt3a protein may inhibit the process of proliferation in keratinocytes, which would be useful for future researchers.     

Up-Regulation of Rhoa/Rho Kinase Pathway by Translationally Controlled Tumor Protein in Vascular Smooth Muscle Cells

Translationally controlled tumor protein (TCTP), a repressor for Na,K-ATPase has been implicated in the development of systemic hypertension, as proved by TCTP-over-expressing transgenic (TCTP-TG) mice. Aorta of TCTP-TG exhibited hypercontractile response compared to that of non-transgenic mice (NTG) suggesting dys-regulation of signaling pathways involved in the vascular contractility by TCTP. Because dys-regulation of RhoA/Rho kinase pathway is implicated in increased vascular contractility, we examined whether TCTP induces alterations in RhoA pathway in vascular smooth muscle cells (VSMCs). We found that TCTP over-expression by adenovirus infection up-regulated RhoA pathway including the expression of RhoA, and its downstream signalings, phosphorylation of myosin phosphatase target protein (MYPT-1), and myosin light chain (MLC). Conversely, lentiviral silencing of TCTP reduced the RhoA expression and Rho kinase signalings. Using immunohistochemical and Western blotting studies on aortas from TCTP-TG confirmed the elevated expression of RhoA and increase in p-MLC (phosphorylated MLC). In contrast, down-regulation of RhoA and p-MLC were found in aortas from heterozygous mice with deleted allele of TCTP (TCTP^+/−). We conclude that up-regulation of TCTP induces RhoA-mediated pathway, and that TCTP-induced RhoA plays a role in the regulation in vasculature. Modulation of TCTP may offer a therapeutic target for hypertension and in vascular contractility dysfunction.