Variable impact transportation (VIT) model for energy and environmental impact of hauling truck operation

Purpose

Fuel economy and emissions of heavy-duty trucks greatly vary based on vehicular/environmental conditions. Large-scale infrastructure construction projects require a large amount of material/equipment transportation. Single-parameter generic hauling models may not be the best option for an accurate estimation of hauling contribution in life cycle assessment (LCA) involving construction projects; therefore, more precise data and parameterized models are required to represent this contribution. This paper discusses key environmental/operational variables and their impact on transportation of materials and equipment; a variable-impact transportation (VIT) model accounting for these variables was developed to predict environmental impacts of hauling.

Methods

The VIT model in the form of multi-nonlinear regression equations was developed based on simulations using the U.S. Environmental Protection Agency (EPA)’s Motor Vehicle Emission Simulator (MOVES) to compute all the impact categories in EPA’s TRACI 2.1 and energy consumption of transportation. Considering actual driving cycles of hauling trucks recorded during a pavement rehabilitation project, the corresponding environmental impacts were calculated, and sensitivity analyses were performed. In addition, an LCA case study based on historical pavement reconstruction projects in Illinois was conducted to analyze the contribution of transportation and variability of its impacts during the pavements’ life cycle.

Results and discussion

The importance of vehicle driving cycles was realized from simulation results. The case study results showed that considering driving cycles using the VIT model could increase the contribution of hauling in total life cycle Global Warming Potential (GWP) and total life cycle GWP itself by 2–4 and 3–5%, respectively. In addition to GWP, ranges of other hauling-related impact categories including Smog, Ozone Depletion, Acidification, and Primary Energy Demand from fuel were presented based on the case study. Ozone Depletion ranged from 9 to 45%, and Smog ranged from 11 to 48% of the total relevant life cycle impacts. The GWP contribution of hauling in pavement LCA ranged between 5 and 32%. The results indicate that the contribution of hauling transportation can be significant in pavement LCA.

Conclusions

For large-scale roadway infrastructure construction projects that need a massive amount of material transportation, high fidelity models and data should be used especially for comparative LCAs that can be used as part of decision making between alternatives. The VIT model provides a simple analytical platform to include the critical vehicular/operational variables without any dependence on an external software; the model can also be incorporated in those studies where some of the transportation activity data are available.

     

Environmental and economic impact of using new-generation wide-base tires

Purpose

New-generation wide-base tire (NG-WBT) is known for improving fuel economy and at the same time for potentially causing a greater damage to pavement. No study has been conducted to evaluate the net environmental saving of the combined system of pavements and NG-WBT. This study adopted a holistic approach (life cycle assessment [LCA] and life cycle costing [LCC]) to quantitatively evaluate the environmental and economic impact of using NG-WBT.

Methods

The net effect of different levels of market penetration of NG-WBT on energy consumption, global warming potential (GWP), and cost based on the fatigue cracking and rutting performance of two different asphalt concrete (AC) pavement structures was evaluated. The performance of pavements was determined based on pavement design lives; pavement surface characteristics, and pavement critical strain responses obtained from the artificial neural network (ANN) based on finite element (FE) simulations were used to calculate design lives of pavements. Based on the calculated design lives, life cycle inventory (LCI) and cost databases, and rolling resistance (RR) models previously developed by the University of Illinois at Urbana-Champaign (UIUC) were used to calculate the environmental and economic impact of the combined system.

Results and discussion

The fuel economy improvement using NG-WBT is 1.5% per axle. Scenario-based case studies were conducted. Considering 0% NG-WBT market penetration (or 100% standard dual tire assembly [DTA]) as a baseline, scenario 1 assumed the same fatigue and rutting potential between NG-WBT and DTA; therefore, the only difference came from fuel economy improvement of using NG-WBT. In scenario 2, pavement fatigue cracking potential determined the pavement design life; both thick and thin AC overlay sections experienced positive net environmental savings, but mixed net economic savings. In scenario 3, pavement rutting potential determined the pavement design life; the thick AC overlay section experienced positive net environmental savings, but mixed net economic savings. The thin section experienced negative net environmental and economic savings.

Conclusions

The outcomes of scenario-based case studies indicated that NG-WBT can result in significant savings in life cycle energy consumption and cost, and GWP; however, these benefits were sensitive to the method used to determine the pavement performance; especially, a small change in pavement strain can result in significant change in pavement life. In addition, the effect of fuel price/economy improvement, discount rate, and International Roughness Index (IRI) threshold values was studied in the sensitivity analyses.

     

Sucrose Synthase (SuSy) Gene Expression: An Indicator for Cotton Fiber Initiation and Early Development

Russian Journal of Plant Physiology - Cotton (Gossypium hirsutum L.) fiber initiation from ovule epidermal cells happen from 0 to 5 DPA, invertase (INV) and sucrose synthase (SuSy) are...     

Investigation of the solid state properties of amoxicillin trihydrate and the effect of powder pH

The purpose of this research was to investigate some physicochemical and solid-state properties of amoxicillin trihydrate (AMT) with different powder pH within the pharmacopoeia-specified range. AMT batches prepared using Dane salt method with the pH values from 4.39 to 4.97 were subjected to further characterization studies. Optical and scanning electron microscopy showed that different batches of AMT powders were similar in crystal habit, but the length of the crystals increased as the pH increased. Further solid-state investigations using powder x-ray diffraction (PXRD) demonstrated the same PXRD pattern, but the intensity of the peaks raised by the powder pH, indicated increased crystallinity. Differential scanning calorimetry (DSC) studies further confirmed that as the powder pH increased, the crystallinity and, hence, thermal stability of AMT powders increased. Searching for the possible cause of the variations in the solid state properties, HPLC analysis showed that despite possessing the requirements of the United States Pharmacopoeia (USP) for purity/impurity profile, there was a direct relationship between the increase of the powder pH and the purity of AMT, and also decrease in the impurity I (alpha-Hydroxyphenylglycine) concentration in AMT powder. Recrystallization studies confirmed that the powder pH could be controlled by adjusting the pH of the crystallization.     

Self-assembling supramolecular complexes by single-stranded extension from plasmid DNA

Self-assembling supramolecular complexes are of great interest for bottom-up research like nanotechnology. DNA is an inexpensive building block with sequence-specific self-assembling capabilities through Watson-Crick and/or Hoogsteen base pairing and could be used for applications in surface chemistry, material science, nanomechanics, nanoelectronics, nanorobotics, and of course in biology. The starting point is usually single-stranded DNA, which is rather easily accessible for base pairing and duplex formation. When long stretches of double-stranded DNA are desirable, serving either as genetic codes or electrical wires, bacterial expansion of plasmids is an inexpensive approach with scale-up properties. Here, we present a method for using double-stranded DNA of any sequence for generating simple structures, such as junctions and DNA lattices. It is known that supercoiled plasmids are strand-invaded by certain DNA analogs. Here we add to the complexity by using "Self-assembling UNiversal (SUN) anchors" formed by DNA analog oligonucleotides, synthesized with an extension, a "sticky-end" that can be used for further base pairing with single-stranded DNA. We show here how the same set of SUN anchors can be utilized for gene therapy, plasmid purification, junction for lattices, and plasmid dimerization through Watson-Crick base pairing. Using atomic force microscopy, it has been possible to characterize and quantify individual components of such supra-molecular complexes.     

Concurrent determination of ezetimibe and its phase-I and II metabolites by HPLC with UV detection: quantitative application to various in vitro metabolic stability studies and for qualitative estimation in bile

Simultaneous separation and quantification of ezetimibe (EZM) and its phase-I metabolite i.e., ezetimibe ketone (EZM-K) and phase-II metabolite i.e., ezetimibe glucuronide (EZM-G) in various matrices was accomplished by gradient HPLC with UV detection. The assay procedure involved deproteinization of 500 microL of either incubation or bile sample containing analytes and internal standard (IS, theophylline) with 75 microL acetonitrile containing 25% perchloric acid. An aliquot of 100 microL supernatant was injected onto a C18 column. The chromatographic separation was achieved by gradient elution consisting of 0.05 M formic acid:acetonitrile:methanol:water at a flow rate of 1.0 mL/min. The detection of analyte peaks were achieved by monitoring the eluate using an UV detector set at 250 nm. Nominal retention times of IS, EZM-G, ezetimibe ketone glucuronide (EZM-KG), EZM and EZM-K were 9.39, 24.23, 27.82, 29.04 and 30.56 min, respectively. Average extraction efficiencies of EZM, EZM-G and IS was >75-80% and for EZM-K was >50% from all the matrices tested. Limit of quantitation (LOQ) for EZM, EZM-K and EZM-G was 0.02 microg/mL. Due to the lack of availability of reference standard of EZM-KG, the recovery and LOQ aspects for this metabolite were not assessed. Overall, the method is suitable for simultaneous measurement of EZM, and its phase-I and phase-II metabolite (EZM-G) in in vitro and in vivo studies.     

Identifying Statistical Dependence in Genomic Sequences via Mutual Information Estimates

Questions of understanding and quantifying the representation and amount of information in organisms have become a central part of biological research, as they potentially hold the key to fundamental advances. In this paper, we demonstrate the use of information-theoretic tools for the task of identifying segments of biomolecules (DNA or RNA) that are statistically correlated. We develop a precise and reliable methodology, based on the notion of mutual information, for finding and extracting statistical as well as structural dependencies. A simple threshold function is defined, and its use in quantifying the level of significance of dependencies between biological segments is explored. These tools are used in two specific applications. First, they are used for the identification of correlations between different parts of the maize zmSRp32 gene. There, we find significant dependencies between the untranslated region in zmSRp32 and its alternatively spliced exons. This observation may indicate the presence of as-yet unknown alternative splicing mechanisms or structural scaffolds. Second, using data from the FBI''s combined DNA index system (CODIS), we demonstrate that our approach is particularly well suited for the problem of discovering short tandem repeats—an application of importance in genetic profiling.[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22]     

Characterization of <Emphasis Type="Italic">Mycobacterium tuberculosis</Emphasis> Central Asian Strain1 using mycobacterial interspersed repetitive unit genotyping

Background  

The Central Asian Strain1 (CAS1) genogroup of Mycobacterium tuberculosis (MTB) is the most prevalent in Pakistan, India and Bangladesh. Mycobacterial interspersed repetitive units variable number tandem repeat (MIRU-VNTR) typing is a reliable and reproducible method for differentiation of MTB isolates. However, information of its utility in determining the diversity of CAS1 strain is limited. We performed standard 12 loci based MIRU-VNTR typing on previously spoligotyped CAS1 strains and 'unique' strains in order to evaluate its discriminatory power for these isolates.