Life Cycle Assessment of Natural Gas-Powered Personal Mobility Options

The recent expansion of unconventional natural gas production in the United States has enabled a steady increase of its use in all consumption sectors, including transportation. In this study, the environmental footprints of three natural gas-based personal mobility options are examined from a life cycle perspective: battery electric vehicles (BEVs), compressed natural gas vehicles (CNGVs), and fuel cell vehicles (FCVs). The results suggest that natural gas-powered vehicles have the potential to considerably reduce the overall environmental impact associated with driven miles in comparison to conventional petroleum-powered internal combustion engine vehicles (PICVs). BEVs and FCVs in particular offer significant reductions in greenhouse gas emissions, especially if carbon capture and sequestration (CCS) technologies are implemented at the fuel conversion facilities. It was furthermore determined that the use phase dominates the life cycle impacts of all of the vehicles considered, although the manufacture of power sources for BEVs and FCVs significantly contributes to their respective environmental burdens. Efforts presently being exerted for the greener manufacture and more efficient powertrain design of BEVs and FCVs are likely to further extend their environmental advantages over CNGVs for the utilization of natural gas as a transportation energy resource

Additional file 1 of Male spiny frogs enter the underwater battlefield with loose skin exhibiting enhanced penetration of capillaries into the epidermis

Additional file 1: Figure S1. Plots between the extent of capillaries penetrating the epidermis, thickness of the epidermis, perfused subepidermal capillary density, and stratum compactum thickness across ten body regions in Leptobrachium boringii. Symbols are used to distinguish individuals of the same group, and regional mean values are plotted. The P values were derived from generalized linear mixed models where individual was included as a random factor. MDPL: average minimum diffusion path length of subepidermal capillaries

Chi-square tests of the relationship between genes functions and phylogenetic hypotheses.

<p>Only significant results are presented. A: the archosaur hypothesis; L: the lepidosaur hypothesis; O: other hypotheses. +: number of genes which have a particular GO category or KEGG pathway; −: number of genes which do not have the GO category or KEGG pathway. Numbers in parentheses are expected numbers of genes under random distribution. For example, of the 2117 genes that support the Archosaur hypothesis, 2036 genes have the GO category of “biological process”; among them, 61 have the GO category of “organophosphate metabolic process” and 1975 genes do not have the term.</p

The phylogenetic hypotheses derived from the 7-species data.

<p>Amino-acid and nucleotide sequences were analyzed by maximum parsimony (MP) and maximum likelihood (ML) methods, respectively. Numbers near the nodes are bootstrap values.</p

Alternative placements of turtles in the current phylogeny of living tetrapods.

<p>Alternative placements of turtles in the current phylogeny of living tetrapods.</p

A simple tally of genes that support alternative hypotheses.

<p>Hu = <u>Hu</u>man (<i>Homo sapiens</i>), Fr = Western Clawed <u>Fr</u>og (<i>Xenopus tropicalis</i>), ZF = <u>Z</u>ebra <u>F</u>inch (<i>Taeniopygia guttata</i>), Ch = <u>Ch</u>icken (<i>Gallus gallus</i>), An = Green <u>An</u>ole (<i>Anolis carolinensis</i>), PT = Chinese <u>P</u>ond <u>T</u>urtle (<i>Mauremys reevesii</i>), ST = <u>S</u>oft-shelled <u>T</u>urtle (<i>Pelodiscus sinensis</i>), Py = Royal <u>Py</u>thon (<i>Python regius</i>), Tu = <u>Tu</u>atara (<i>Sphenodon punctatus</i>), Op = <u>Op</u>ossum (<i>Monodelphis domestica</i>), Cr = Nile <u>Cr</u>ocodile (<i>Crocodylus niloticus</i>).</p><p>For example, the clade ((ZF,Ch),PT) appears on 2117 gene trees without regarding other relationships. The 7-species dataset includes 4,584 putatively orthologous proteins and coding genes; the 11-species dataset includes 1,638 putatively orthologous proteins and coding genes.</p

Chi-square test of the relationship between genes under positive selection and alternative hypotheses.

<p>ZF = <u>Z</u>ebra <u>F</u>inch (<i>Taeniopygia guttata</i>), Ch = <u>Ch</u>icken (<i>Gallus gallus</i>), PT = Chinese <u>P</u>ond <u>T</u>urtle (<i>Mauremys reevesii</i>), An = Green <u>An</u>ole (<i>Anolis carolinensis</i>).</p><p>Numbers in parentheses are expected numbers of genes under random distribution. Significantly more positively selected genes support the archosaur hypothesis.</p

The phylogenetic hypotheses derived from using genes as characters.

<p>Individual gene tree was first estimated and used as character-state tree. Each gene was then treated as a character and a parsimony analysis was used to construct the species trees. Amino-acid and nucleotide sequences were analyzed separately. Numbers near the nodes are bootstrap values. Note the different placements of turtles and the low bootstrap values for the associated nodes.</p

Synthesis of 2‑Amino-3-hydroxy‑3<i>H</i>‑indoles via Palladium-Catalyzed One-Pot Reaction of Isonitriles, Oxygen, and <i>N</i>‑Tosylhydrazones Derived from 2‑Acylanilines

A cyanide-free one-pot procedure was developed to access 2-amino-3-hydroxy-3<i>H</i>-indoles, which involved: (1) <i>in situ</i> formation of ketenimines by the reaction of <i>N</i>′-(1-(2-amino­phenyl)­ethylidene)-<i>p</i>-tosyl­hydrazones with isonitriles; (2) the intramolecular nucleophilic attack of ketenimines by the amino in phenyl furnishing the ring closure leading to 2-aminoindoles; (3) the oxidation of 2-aminoindoles by O₂ leading to 2-amino-3-hydroxy-3<i>H</i>-indoles. This strategy represents not only a key compliment to the sporadic synthetic methods toward 2-amino-3-hydroxy-3<i>H</i>-indoles but also progress in <i>N-</i>tosylhydrazone, isonitrile, and ketenimine chemistry

The phylogenetic hypotheses derived from the 11-species data.

<p>Amino-acid and nucleotide sequences were analyzed by maximum parsimony (MP) and maximum likelihood (ML) methods, respectively. A Bayesian tree from nucleotide sequences and a MP tree from the 1^st and 2^nd codon position sequences are also presented. Numbers near the nodes are bootstrap values or Bayesian posterior probabilities (E).</p