Wheel Load Distribution in Simply Supported Concrete Slab Bridges

This paper presents the results of a parametric study related to the wheel load distribution in one-span, simply supported, multilane, reinforced concrete slab bridges. The finite-element method was used to investigate the effect of span length, slab width with and without shoulders, and wheel load conditions on typical bridges. A total of 112 highway bridge case studies were analyzed. It was assumed that the bridges were stand-alone structures carrying one-way traffic. The finite-element analysis (FEA) results of one-, two-, three-, and four-lane bridges are presented in combination with four typical span lengths. Bridges were loaded with highway design truck HS20 placed at critical locations in the longitudinal direction of each lane. Two possible transverse truck positions were considered: (1) Centered loading condition where design trucks are assumed to be traveling in the center of each lane; and (2) edge loading condition where the design trucks are placed close to one edge of the slab with the absolute minimum spacing between adjacent trucks. FEA results for bridges subjected to edge loading showed that the AASHTO standard specifications procedure overestimates the bending moment by 30% for one lane and a span length less than 7.5 m (25 ft) but agrees with FEA bending moments for longer spans. The AASHTO bending moment gave results similar to those of the FEA when considering two or more lanes and a span length less than 10.5 m (35 ft). However, as the span length increases, AASHTO underestimates the FEA bending moment by 15 to 30%. It was shown that the presence of shoulders on both sides of the bridge increases the load-carrying capacity of the bridge due to the increase in slab width. An extreme loading scenario was created by introducing a disabled truck near the edge in addition to design trucks in other lanes placed as close as possible to the disabled truck. For this extreme loading condition, AASHTO procedure gave similar results to the FEA longitudinal bending moments for spans up to 7.5 m (25 ft) and underestimated the FEA (20 to 40%) for spans between 9 and 16.5 m (30 and 55 ft), regardless of the number of lanes. The new AASHTO load and resistance factor design (LRFD) bridge design specifications overestimate the bending moments for normal traffic on bridges. However, LRFD procedure gives results similar to those of the FEA edge+truck loading condition. Furthermore, the FEA results showed that edge beams must be considered in multilane slab bridges with a span length ranging between 6 and 16.5 m (20 and 55 ft). This paper will assist bridge engineers in performing realistic designs of simply supported, multilane, reinforced concrete slab bridges as well as evaluating the load-carrying capacity of existing highway bridges.     

Separation and preconcentration of La from monazite, followed by determination using nondestructive γ-ray spectrometry

A method was developed for separation, preconcentration, and determination of La by its radioactive isotope ¹³⁸La using an HPGe detector. The method was checked by comparison with ICP-MS. The detection limit (minimum detection activity) is 1.46 and 1.52 Bq kg^?1 at 788.4 and 1435.8 keV lines, respectively. The Th(IV) and U(VI) are separated by precipitation. To separate Ac(III), it is extracted jointly with REEs from 0.1 M HNO₃ with HDEHP and then stripped with 0.2 M HNO₃, with REEs remaining in the organic phase. Lanthanum in a mixture with REEs is determined by ??-ray spectrometry.     

Combined Modeling Study of the Binding Characteristics of Natural Compounds,Derived from Psoralea Fruits,to β-Amyloid Peptide Monomer

A dysfunctional protein aggregation in the nervous system can lead to several neurodegenerative disorders that result in intracellular inclusions or extracellular aggregates. An early critical event within the pathogenesis of Alzheimer’s disease is the accumulation of amyloid beta peptide within the brain. Natural compounds isolated from Psoralea Fructus (PF) have significant anti-Alzheimer effects as strong inhibitors of Aβ42 aggregation. Computer simulations provide a powerful means of linking experimental findings to nanoscale molecular events. As part of this research four prenylated compounds, the active ingredients of Psoralea Fructus (PF), were studied as Aβ42 accumulation inhibitors using molecular simulations modeling. In order to resolve the binding modes of the ligands and identify the main interactions of Aβ42 residues, we performed a 100 ns molecular dynamics simulation and binding free energy calculations starting from the model of the compounds obtained from the docking study. This study was able to pinpoint the key amino acid residues in the Aβ42 active site and provide useful information that could benefit the development of new Aβ42 accumulation inhibitors.     

Observing single cell NF-κB dynamics under stimulant concentration gradient

Study of cell signaling often requires examination of the cellular dynamics under variation in the stimulant concentration. Such variation has typically been conducted by dispensing cell populations in a number of chambers or wells containing discrete concentrations. Such practice adds to the complexity associated with experimental or device design and requires substantial labor for implementation. Furthermore, there is also potential risk of missing important results due to the often arbitrary selection of discrete concentration values for testing. In this Letter, we study NF-κB activation and translocation at the single cell level using a microfluidic device that generates continuously varying concentration gradient. We use only three device settings to cover stimulant (interleukin-1β) concentrations of 4 orders of magnitude (0.001-10 ng/mL). Such device allows us to study temporal dynamics of NF-κB in single cells under different stimulant concentrations by real-time imaging. Interestingly, our results reveal that, while the percent of cells with NF-κB translocation decreases with lower stimulant concentration in the range of 0.1-0.001 ng/mL, the response time of such translocation remains constant, reflected by the single cell data.     

The PCDD/PCDF Dioxin Releases in the Climate of Environment of Jordan in the Period （2000-2008）

Many environment problems of the full using of several categories of processing include mining, heat generators, direct combustion of forest fires, cement production, power plant, transport, medical waste. Dioxin/furan releases from these categories are one of these environment problems. Possible lines of reducing the PCDD/ PCDF （Polychlorinated dibenzo-para-dioxins/Polychlorinated dibenzofurans） releases from these categories are eluci- dated. The contribution of this paper is present the identification and estimation of the latest figure of dioxin/furan releases in the climate of environment of Jordan in the period 2000-2008 from the following categories （cement, aluminum, ceramic, medical waste, power plant, land fill, ferrous and non- ferrous metals, uncontrolled combustion process （biomass burning, waste burning, accidental fires in house, transport）. These finding shows the sign of growth of estimated PCDD/PCDF releases from categories which did not calculated and followed after 2003. The result shows the highest PCDD/PCDF release from landfill fires （62.75 g TEQ/year）, medical waste （8.8264 g TEQ/year）, and transport （3.0145 g TEQ/year）. Jordan seeks by next years, a reduction in total releases of dioxins and furans from sources resulting from human activity. This challenge will apply to the aggregate of releases to the air nationwide and of releases to the water within the Jordan area. Jordan should conduct air monitoring for dioxin in order to track fluctuations in atmospheric deposition levels.     

Thermal degradation study of polymethylmethacrylate with AlI3 nanoadditive

Organic polymers in the process of thermal degradation produce a lot of toxic fragments. In this work, we designed a new method of degradation of polymethylmethacrylate (PMMA) materials with aluminum triiodide nanoadditives (AlI₃ NAs). In the present research work, a thermal degradation study of PMMA blends with AlI₃ NAs was carried out by using a specially designed pyrolytic assembly. Different blends of PMMA with AlI₃ (P0, P3, P6, P9, P12, and P15) were prepared by changing the concentration of AlI₃ NAs from 0% to 15%. FTIR and TGA studies show the stability of polymers with AlI₃ NAs. Scanning electron microscopy analysis shows All₃ spread uniformly at nanoscale throughout the polymer matrix. Horizontal burning test (HBT) test confirms that polymer burning is retarded with AlI₃ NAs.     

Correction to: Physico-Chemical Aspects on Uranium and Molybdenum Extraction from Aqueous Solution by Synthesized Phosphinimine Derivative Chelating Agent

Journal of Inorganic and Organometallic Polymers and Materials -     

Cluster Based Routing Protocol for Mobile Nodes in Wireless Sensor Network

Mobility of sensor nodes in wireless sensor network (WSN) has posed new challenges particularly in packet delivery ratio and energy consumption. Some real applications impose combined environments of fixed and mobile sensor nodes in the same network, while others demand a complete mobile sensors environment. Packet loss that occurs due to mobility of the sensor nodes is one of the main challenges which comes in parallel with energy consumption. In this paper, we use cross layer design between medium access control (MAC) and network layers to overcome these challenges. Thus, a cluster based routing protocol for mobile sensor nodes (CBR-Mobile) is proposed. The CBR-Mobile is mobility and traffic adaptive protocol. The timeslots assigned to the mobile sensor nodes that had moved out of the cluster or have not data to send will be reassigned to incoming sensor nodes within the cluster region. The protocol introduces two simple databases to achieve the mobility and traffic adaptively. The proposed protocol sends data to cluster heads in an efficient manner based on received signal strength. In CBR-Mobile protocol, cluster based routing collaborates with hybrid MAC protocol to support mobility of sensor nodes. Schedule timeslots are used to send the data message while the contention timeslots are used to send join registration messages. The performance of proposed CBR-Mobile protocol is evaluated using MATLAB and was observed that the proposed protocol improves the packet delivery ratio, energy consumption, delay and fairness in mobility environment compared to LEACH-Mobile and AODV protocols.     

Removal of synthetic reactive dyes from textile wastewater by Sorel's cement

Removal of some reactive dyes (RY-145, RR-194 and RB-B) from textile wastewater effluents using Sorel's cement is described. Parameters affecting dye uptake including contact time, reagent dosage and pH are examined and optimized. Dye adsorption equilibrium data are fitted well to the Langmiur isotherm rather than Freundlish isotherm. The adsorption isotherm indicates that the adsorption capacities are 107.67, 120.89 and 103.14 mg dye per gram of Sorel's cement for RY-145, RR-194 and RB-B reactive dyes, respectively. The adsorption isotherms, including Langmuir constant (Q degrees and b) and Frendlich constant (K(F) and n), for the dyes decrease with the increase of temperature. The values of enthalpy change (DeltaH) for RY-145, RR-194 and RB-B dyes are -146.96, -49.23 and -264.86 kJ mol(-1), respectively, indicating that the removal process is exothermic. The sorption of the dyes is enhanced by increasing the pH, reaching a maximum at pH 6-11. Experimental runs conducted to measure the chemical oxygen demand (COD) of textile wastewater loaded with reactive dyes, reveal approximately 96% removal of the COD contents within 30 min under optimized conditions.     

Probiotics Affect One‐Carbon Metabolites and Catecholamines in a Genetic Rat Model of Depression

1 Scope

Probiotics may influence one‐carbon (C1) metabolism, neurotransmitters, liver function markers, or behavior.

2 Methods and results

Male adult Flinders Sensitive Line rats (model of depression, FSL; n = 22) received Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 (10⁹ or 10¹⁰ colony‐forming units per day) or vehicle for 10 weeks. The controls, Flinders Resistant Line rats (FRL, n = 8), only received vehicle. C1‐related metabolites were measured in plasma, urine, and different tissues. Monoamine concentrations were measured in plasma, hippocampus, and prefrontal cortex. Vehicle‐treated FSL rats had higher plasma concentrations of betaine, choline, and dimethylglycine, but lower plasma homocysteine and liver S‐adenosylmethionine (SAM) than FRLs. FSL rats receiving high‐dose probiotics had lower plasma betaine and higher liver SAM compared to vehicle‐treated FSL rats. FSLs had higher concentrations of norepinephrine, dopamine, and serotonin than FRLs across various brain regions. Probiotics decreased plasma dopamine in FSLs in a dose‐dependent manner. There were no detectable changes in liver function markers or behavior.

3 Conclusions

Probiotics reduced the flow of methyl groups via betaine, increased liver SAM, and decreased plasma dopamine and norepinephrine. Since these changes in methylation and catecholamine pathways are known to be involved in several diseases, future investigation of the effect of probiotics is warranted.