Laboratory Measurements of Flow through Culverts

Laboratory apparatus to simulate flow through culverts has been used to collect discharge and water level measurements. Two different shapes of culvert barrels, namely square and circular, were tested. The measurements presented in this note are intended to provide useful information regarding the variety of flow regimes (including overtopping) through culverts, and the transitions from one flow regime to another. It is known that modeling the culvert flow regimes and capturing the transitions among these regimes numerically is a challenging task. To that effect, the laboratory measurements presented herein can provide a testing and validation data set for numerical modeling of hydraulic structures such as culverts.     

Class I/Class IIa bacteriocin cross-resistance phenomenon in Listeria monocytogenes

Variants resistant to nisin A (vA), nisin Z (vZ), pediocin PA-1 (vP), divergicin M35 (vD) and to bacteriocin-like compounds produced by Bifidobacterium thermophilum subsp. infantis RBL67 (vB) were developed from Listeria monocytogenes LSD530. Lactic acid production, specific growth rate, potassium ion efflux, susceptibility to 13 antibiotics, cell-envelope fatty acid composition and bacteriocin cross-resistance were evaluated. Lactic acid production decreased to 75% or less of that by strain LSD530 for vP, vD and vB and to 20% or less for vA and vZ. Specific growth rates also decreased for all five variants. Acquired resistance to nisin A or Z increased resistance to pediocin and divergicin while vD showed increased resistance to nisin Z but decreased resistance to nisin A and vP exhibited increased resistance to nisin Z, pediocin and divergicin but decreased resistance to nisin A. Acquired bacteriocin resistance generally decreased antibiotic sensitivity, particularly to ampicillin, chloramphenicol, erythromycin and tetracycline. Palmitic acid (C(16:0)) in the cell wall fraction of all variants was significantly higher than in strain LSD530, accounting for 18%, 43%, 32%, 26%, 53% and 44% of the total fatty acids for LSD530, vP, vD, vB, vA, and vZ, respectively. The relationship between the acquisition of bacteriocin resistance, cross-resistance and pathogenicity of Listeria monocytogenes should be studied.     

Cyclic loading and fracture mechanics of Ductal<Superscript>®</Superscript> concrete

Reactive Powder Concrete (RPC) is a special type of ultra high strength, superplasticized, silica fume concrete, often fibre-reinforced, with improved homogeneity because the traditional coarse and fine aggregate are replaced by fine sand with particle sizes in the range of 100–400 μm [4–16 thousandths of an inch]. RPC properties are attractive because compressive strengths up to 800 MPa [116 ksi] have been recorded, but more typically in excess of 200 MPa [29 ksi]. Flexural strengths up to 141 MPa [20.4 ksi] and fracture energy of 40 kJ/m²[kJ/in.²] have been reported—the latter achieved when steel or stainless steel fibres were included in the mix (Baché (1998) Proceedings of the 2nd international conference on superplasticizers in concrete, Ottawa, pp 35–41; Coppola et al. L’Industria Ital Cemento 707:112–125 (1996); Blais and Couture PCI J 44(5):60–71 (1999); Richard and Cheyrezy (1994) Proceedings of V. Mohan Malhotra symposium on concrete technology: past, present, and future (SP 144). American Concrete Institute, Detroit, pp 507–518; Richard and Cheyrezy Cement Concrete Res 25(7):1501–1511 (1995)). Ductal^®, a commercial RPC, has a compressive strength of approximately 150 MPa [22 ksi] with metallic or organic fibres. All tests described here were performed on 40 × 40 × 160 mm [1.6 × 1.6 × 6.3 in.] (Width (b) × Depth (d) × length (L)) prisms with Poly Vinyl Alcohol (PVA) fibres. Ductal^® is a family of RPC and micro-defect-free concretes containing micro silica, silica fume, cement, Quartz sand, superplasticizer, and PVA fibres. Mechanical and fracture parameters were investigated using four point bending. Low and high cyclic fatigue tests were conducted in three stages, starting from low to high strain cycles. Cracks generated by cyclic fatigue tests were monitored periodically in order to evaluate the rate of crack propagation. Cracks were also investigated using a high magnification microscope. Three pairs of specimens were tested, notched and un-notched to evaluate fracture parameters. Four point bending was used again because determination of the J-Integral (J _IC ) requires the application of pure bending over a portion of the beam. Load was applied at the third points over a span (S) of 120 mm [4.7 in.], providing a span to depth ratio (S/d) of 3.0. Specimens were notched using a 1 mm [0.04 in.] thick diamond saw. The crack tip generated was circular and the crack length (s) was approximately 10 mm [0.4 in.]. Tests on the notched specimens included measurement of the crack mouth opening displacement (CMOD). Closed-loop testing was developed using a feed back signal from the (CMOD) clip gauge attached to the notched specimens and from strain gauges attached to the un-notched specimens. The weight (w) of each specimen was obtained prior to testing. Fracture parameters were calculated from the load–deflection curves obtained from the notched and un-notched specimens.     

A comparative study on treatment of wastewaters with various biodegradability and various pH values using single‐chamber microbial fuel cells

This work assessed the performance of a single‐chamber microbial fuel cell (MFC) with various substrates. Primary settled domestic wastewaters were used to simulate wastewaters of high biodegradability; while phenol‐based wastewaters and benzene‐based wastewaters were used to simulate wastewaters of low biodegradability. Experiments were performed at initial pH values of 6, 7 and 8. The maximum voltage production, power density and removal of substrate were obtained using primary settled domestic wastewater, whereas the lowest values were obtained using phenol‐based wastewater. The maximum chemical oxygen demand removal efficiency, phenol removal efficiency and benzene removal efficiency were 80.8, 63.3 and 77.8%, respectively. The performance of the MFC was enhanced by increasing the influent pH. The lowest coulombic efficiencies were obtained from phenol‐based wastewater and benzene‐based wastewater, which indicated that electrogenic bacteria were not the primary microorganisms responsible for the biodegradation of low biodegradable wastewater.     

Influence of heat treatment on the optoelectronic performance of electrodeposited CdSe thin films

Journal of Materials Science: Materials in Electronics - In this work, a thin film of Cadmium selenide is deposited on fluorine tin oxide-coated glass substrate through a simplified 2-electrode...     

Utilizing spray drying technique to improve oral bioavailability of apigenin

The aim of this study was to prepare, characterize, and evaluate apigenin in a solid dispersion system to improve the dissolution rate and bioavailability of such poorly soluble drug. Apigenin was dissolved in organic solvent with micelle forming polymer Pluronic F-127 (PL-F127). Solid dispersion of apigenin-PL F-127 was developed using spray drying technique. Physicochemical and in vitro characterization of the produced solid dispersion particles were conducted using scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, powder X-ray diffractometry and dissolution study. In addition, in vivo study was performed for the spray dried versus pure and marketed apigenin. C_max was found to be around 5 folds higher for spray dried product compared to non spray dried materials. The prepared drug:polymer formulation showed elongated particles and complete lack of crystallinity at 1:4 ratio. The change in the vibrational wave numbers strongly suggested the formation of hydrogen bonding between apigenin and PL F-127. Significant increase in the dissolution rate and bioavailability of the spray dried apigenin showed the potential of solid dispersion system to overcome problem related to BCS II drugs.     

ROI-Driven Cyber Risk Mitigation Using Host Compliance and Network Configuration

Automated cyber security configuration synthesis is the holy grail of cyber risk management. The effectiveness of cyber security is highly dependent on the appropriate configuration hardening of heterogeneous, yet interdependent, network security devices, such as firewalls, intrusion detection systems, IPSec gateways, and proxies, to minimize cyber risk. However, determining cost-effective security configuration for risk mitigation is a complex decision-making process because it requires considering many different factors including end-hosts’ security weaknesses based on compliance checking, threat exposure due to network connectivity, potential impact/damage, service reachability requirements according to business polices, acceptable usability due to security hardness, and budgetary constraints. Although many automated techniques and tools have been proposed to scan end-host vulnerabilities and verify the policy compliance, existing approaches lack metrics and analytics to identify fine-grained network access control based on comprehensive risk analysis using both the hosts’ compliance reports and network connectivity. In this paper, we present new metrics and a formal framework for automatically assessing the global enterprise risk and determining the most cost-effective security configuration for risk mitigation considering both the end-host security compliance and network connectivity. Our proposed metrics measure the global enterprise risk based on the end-host vulnerabilities and configuration weaknesses, collected through compliance scanning reports, their inter-dependencies, and network reachability. We then use these metrics to automatically generate a set of host-based vulnerability fixes and network access control decisions that mitigates the global network risk to satisfy the desired Return on Investment of cyber security. We solve the problem of cyber risk mitigation based on advanced formal methods using Satisfiability Module Theories, which has shown scalability with large-size networks.     

Analyzing the Simple Ranking and Selection Process for Constrained Evolutionary Optimization

Many optimization problems that involve practical applications have functional constraints,and some of these constraints are active,meaning that they prevent any solution from improving the objective function value to the one that is better than any solution lying beyond the constraint limits.Therefore,the optimal solution usually lies on the boundary of the feasible region.In order to converge faster when solving such problems,a new ranking and selection scheme is introduced which exploits this feature ...     

Real-time automatic message accounting data transport

In today’s operation, all usage records for billing, regardless of their source, and service type are put into a file/stream and delivered to the downstream revenue accounting office for processing. The revenue accounting office operates in a batch mode, then scans through the records and separates those which are required for special processing by other applications, like fraud management and customer access to network usage data. However, there is a significant delay between the time the usage records are generated to the time they are available to the other systems. This paper proposes solutions to support real-time transfer of automatic message accounting (AMA) records and files. First, the existing automatic message accounting teleprocessing system (AMATPS) architecture is analyzed to study its limitations. Next, transport mechanisms are identified and analyzed. Finally, an alternative to the existing AMATPS architecture is discussed.     

Bayesian Analysis in Partially Accelerated Life Tests for Weighted Lomax Distribution

Accelerated life testing has been widely used in product life testing experiments because it can quickly provide information on the lifetime distributions by testing products or materials at higher than basic conditional levels of stress, such as pressure, temperature, vibration, voltage, or load to induce early failures. In this paper, a step stress partially accelerated life test (SS-PALT) is regarded under the progressive type-II censored data with random removals. The removals from the test are considered to have the binomial distribution. The life times of the testing items are assumed to follow length-biased weighted Lomax distribution. The maximum likelihood method is used for estimating the model parameters of length-biased weighted Lomax. The asymptotic confidence interval estimates of the model parameters are evaluated using the Fisher information matrix. The Bayesian estimators cannot be obtained in the explicit form, so the Markov chain Monte Carlo method is employed to address this problem, which ensures both obtaining the Bayesian estimates as well as constructing the credible interval of the involved parameters. The precision of the Bayesian estimates and the maximum likelihood estimates are compared by simulations. In addition, to compare the performance of the considered confidence intervals for different parameter values and sample sizes. The Bootstrap confidence intervals give more accurate results than the approximate confidence intervals since the lengths of the former are less than the lengths of latter, for different sample sizes, observed failures, and censoring schemes, in most cases. Also, the percentile Bootstrap confidence intervals give more accurate results than Bootstrap-t since the lengths of the former are less than the lengths of latter for different sample sizes, observed failures, and censoring schemes, in most cases. Further performance comparison is conducted by the experiments with real data.