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36 results for “endotherm”
The past, present, and future of predator-prey interactions in a warming world: using species distribution modeling to forecast ectotherm-endotherm niche overlap
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Data from: Parameters used in the endotherm biophysical model for each species
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The thermal performance curve for aerobic metabolism of a flying endotherm
<p>Performance benefits of stable, warm muscles are believed to be important for the evolution of endothermy in mammals, birds, and flying insects. However, thermal performance curves have never been measured for a free-flying endotherm, as it is challenging to vary body temperatures of these animals, and maximal flight performance is difficult to elicit. We varied air temperatures and gas densities to manipulate thoracic temperatures of flying honey bees from 29-44°C, with low air densities used to increase flight metabolic rates to maximal values. Honey bees showed a clear thermal performance curve with an optimal temperature of 39°C. Maximal flight metabolic rates increased by ~2% per 1°C increase in thoracic temperature at suboptimal thoracic temperatures, but decreased ~5% per 1°C increase as the bees continued to heat up. This study provides the first quantification of the maximal metabolic performance benefit of thermoregulation in an endotherm. These data directly support aerobic capacity models for benefits of thermoregulation in honey bees, and suggest that improved aerobic capacity likely contributes to the multiple origins of endothermic heterothermy in bees and other insects.</p>
Endothermic processes for producing hydrogen using autothermal microchannel reactor technology by steam reforming
<p><strong>Endothermic processes for producing hydrogen using autothermal microchannel reactor technology by steam reforming</strong></p> <p>Junjie Chen</p> <p>Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China</p> <p>Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com</p> <p> </p> <p>A chemical reaction is a process in which one or more substances, the reactants, are converted to one or more different substances, the products. Substances are either chemical elements or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products. Chemical reactions must be distinguished from physical changes. Physical changes include changes of state, such as ice melting to water and water evaporating to vapour. If a physical change occurs, the physical properties of a substance will change, but its chemical identity will remain the same. No matter what its physical state, water is the same compound, with each molecule composed of two atoms of hydrogen and one atom of oxygen. However, if water, as ice, liquid, or vapour, encounters sodium metal, the atoms will be redistributed to give the new substances molecular hydrogen and sodium hydroxide. By this, a chemical change or reaction has occurred. When making a new substance from other substances, chemists say either that they carry out a synthesis or that they synthesize the new material. Reactants are converted to products, and the process is symbolized by a chemical equation. For example, iron and sulfur combine to form iron sulfide.</p> <p>Streamwise distance (meter), Heterogeneous reaction rate along the length of the reactor (mole per square meter per second)</p> <p>0 13.8238</p> <p>0.00025 13.829</p> <p>0.0005 13.7686</p> <p>0.00075 13.5966</p> <p>0.001 13.3629</p> <p>0.00125 13.1109</p> <p>0.0015 12.8776</p> <p>0.00175 12.6771</p> <p>0.002 12.5024</p> <p>0.00225 12.3324</p> <p>0.0025 12.148</p> <p>0.00275 11.9429</p> <p>0.003 11.7223</p> <p>0.00325 11.5024</p> <p>0.0035 11.3004</p> <p>0.00375 11.1228</p> <p>0.004 10.9663</p> <p>0.00425 10.8201</p> <p>0.0045 10.6735</p> <p>0.00475 10.5217</p> <p>0.005 10.3666</p> <p>0.00525 10.2161</p> <p>0.0055 10.079</p> <p>0.00575 9.9589</p> <p>0.006 9.85332</p> <p>0.00625 9.75492</p> <p>0.0065 9.65697</p> <p>0.00675 9.55649</p> <p>0.007 9.45433</p> <p>0.00725 9.35567</p> <p>0.0075 9.26616</p> <p>0.00775 9.18776</p> <p>0.008 9.11867</p> <p>0.00825 9.0535</p> <p>0.0085 8.98726</p> <p>0.00875 8.91821</p> <p>0.009 8.84762</p> <p>0.00925 8.77935</p> <p>0.0095 8.71752</p> <p>0.00975 8.66366</p> <p>0.01 8.61548</p> <p>0.01025 8.56872</p> <p>0.0105 8.51959</p> <p>0.01075 8.46699</p> <p>0.011 8.41232</p> <p>0.01125 8.35897</p> <p>0.0115 8.31019</p> <p>0.01175 8.26698</p> <p>0.012 8.22767</p> <p>0.01225 8.18823</p> <p>0.0125 8.14529</p> <p>0.01275 8.09866</p> <p>0.013 8.04992</p> <p>0.01325 8.00185</p> <p>0.0135 7.95721</p> <p>0.01375 7.91664</p> <p>0.014 7.87854</p> <p>0.01425 7.8395</p> <p>0.0145 7.79682</p> <p>0.01475 7.74993</p> <p>0.015 7.70089</p> <p>0.01525 7.65246</p> <p>0.0155 7.6065</p> <p>0.01575 7.56371</p> <p>0.016 7.52264</p> <p>0.01625 7.48033</p> <p>0.0165 7.43432</p> <p>0.01675 7.38447</p> <p>0.017 7.33228</p> <p>0.01725 7.28009</p> <p>0.0175 7.22957</p> <p>0.01775 7.18109</p> <p>0.018 7.13374</p> <p>0.01825 7.0847</p> <p>0.0185 7.03187</p> <p>0.01875 6.9754</p> <p>0.019 6.91664</p> <p>0.01925 6.85735</p> <p>0.0195 6.79932</p> <p>0.01975 6.74305</p> <p>0.02 6.687</p> <p>0.02025 6.62861</p> <p>0.0205 6.56642</p> <p>0.02075 6.50083</p> <p>0.021 6.43312</p> <p>0.02125 6.3647</p> <p>0.0215 6.29672</p> <p>0.02175 6.22942</p> <p>0.022 6.16121</p> <p>0.02225 6.09054</p> <p>0.0225 6.01672</p> <p>0.02275 5.9398</p> <p>0.023 5.86069</p> <p>0.02325 5.78065</p> <p>0.0235 5.70069</p> <p>0.02375 5.62078</p> <p>0.024 5.53996</p> <p>0.02425 5.45674</p> <p>0.0245 5.37043</p> <p>0.02475 5.28143</p> <p>0.025 5.19039</p> <p>0.02525 5.09831</p> <p>0.0255 5.00598</p> <p>0.02575 4.9134</p> <p>0.026 4.81981</p> <p>0.02625 4.72445</p> <p>0.0265 4.6271</p> <p>0.02675 4.52778</p> <p>0.027 4.42719</p> <p>0.02725 4.32633</p> <p>0.0275 4.22547</p> <p>0.02775 4.12485</p> <p>0.028 4.02385</p> <p>0.02825 3.9231</p> <p>0.0285 3.82001</p> <p>0.02875 3.71778</p> <p>0.029 3.60389</p> <p>0.02925 3.48476</p> <p>0.0295 3.37125</p> <p>0.02975 3.25454</p> <p>0.03 3.09704</p> <p>Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com, Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China</p>
Steam reforming processes using microchannel technology for conducting simultaneous endothermic and exothermic reactions
<p><strong>Steam reforming processes using microchannel technology for conducting simultaneous endothermic and exothermic reactions</strong></p> <p>Junjie Chen</p> <p>Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China</p> <p>Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com</p> <p> </p> <p>Many catalytic processes are known in which the catalyst and the reactants are not present in the same phase, that is, state of matter. These are known as heterogeneous catalytic reactions. They include reactions between gases or liquids or both at the surface of a solid catalyst. Since the surface is the place at which the reaction occurs, it generally is prepared in ways that produce large surface areas per unit of catalyst; finely divided metals, metal gauzes, metals incorporated into supporting matrices, and metallic films have all been used in modern heterogeneous catalysis. The metals themselves are used, or they are converted to oxides, sulfides, or halides. With solid catalysts, at least one of the reactants is chemisorbed (a portmanteau term for chemically adsorbed) by the catalyst. A catalyst is chosen that releases the products formed as readily as possible; otherwise, the products remain on the catalyst surface and act as poisons to the process. Chemisorption can occur over a wide temperature range, the most effective temperature for adsorption depending on the nature of the catalyst. Thus, hydrogen is chemisorbed readily by many metals even at liquid air temperatures. With a series of hydrogenation-dehydrogenation catalysts, for example, zinc oxide-chromic oxide, chemisorption of hydrogen often occurs above room temperature. Nitrogen is rapidly chemisorbed on synthetic ammonia-iron catalyst in the region at temperatures above 400 degrees Celsius. It has been shown that iron films chemisorb nitrogen even at liquid air temperatures, with additional chemisorption found above room temperatures. It follows from such considerations that whereas physical adsorptions, which parallel the ease of liquefaction of the adsorbed substance, occur spontaneously, chemisorption, which involves the making and breaking of chemical bonds, often requires activation energies (energy needed to initiate reactions) as do uncatalyzed chemical processes. To be efficient catalytically, a process must involve energies of activation for all the steps involved that, at their maxima, are less than those required for the uncatalyzed reaction.</p> <p>Streamwise distance (meter), Heterogeneous reaction rate along the length of the reactor (mole per square meter per second)</p> <p>0 9.08258</p> <p>0.00025 9.08623</p> <p>0.0005 9.06858</p> <p>0.00075 9.00579</p> <p>0.001 8.90897</p> <p>0.00125 8.80223</p> <p>0.0015 8.71498</p> <p>0.00175 8.6596</p> <p>0.002 8.62783</p> <p>0.00225 8.59661</p> <p>0.0025 8.54384</p> <p>0.00275 8.46052</p> <p>0.003 8.35118</p> <p>0.00325 8.23399</p> <p>0.0035 8.13034</p> <p>0.00375 8.05024</p> <p>0.004 7.98947</p> <p>0.00425 7.93422</p> <p>0.0045 7.87164</p> <p>0.00475 7.7959</p> <p>0.005 7.70981</p> <p>0.00525 7.62462</p> <p>0.0055 7.55304</p> <p>0.00575 7.50071</p> <p>0.006 7.46372</p> <p>0.00625 7.43144</p> <p>0.0065 7.39358</p> <p>0.00675 7.3462</p> <p>0.007 7.29176</p> <p>0.00725 7.23878</p> <p>0.0075 7.19691</p> <p>0.00775 7.16958</p> <p>0.008 7.15358</p> <p>0.00825 7.14021</p> <p>0.0085 7.12094</p> <p>0.00875 7.09265</p> <p>0.009 7.05774</p> <p>0.00925 7.02353</p> <p>0.0095 6.99801</p> <p>0.00975 6.98414</p> <p>0.01 6.97862</p> <p>0.01025 6.97401</p> <p>0.0105 6.9631</p> <p>0.01075 6.94354</p> <p>0.011 6.91761</p> <p>0.01125 6.89195</p> <p>0.0115 6.87358</p> <p>0.01175 6.86521</p> <p>0.012 6.86398</p> <p>0.01225 6.86277</p> <p>0.0125 6.8552</p> <p>0.01275 6.83935</p> <p>0.013 6.81755</p> <p>0.01325 6.79575</p> <p>0.0135 6.78029</p> <p>0.01375 6.77368</p> <p>0.014 6.77343</p> <p>0.01425 6.7728</p> <p>0.0145 6.76616</p> <p>0.01475 6.75146</p> <p>0.015 6.73076</p> <p>0.01525 6.70987</p> <p>0.0155 6.6946</p> <p>0.01575 6.68733</p> <p>0.016 6.68571</p> <p>0.01625 6.68358</p> <p>0.0165 6.67524</p> <p>0.01675 6.65921</p> <p>0.017 6.6378</p> <p>0.01725 6.61618</p> <p>0.0175 6.59945</p> <p>0.01775 6.59003</p> <p>0.018 6.5862</p> <p>0.01825 6.58161</p> <p>0.0185 6.5713</p> <p>0.01875 6.5542</p> <p>0.019 6.53214</p> <p>0.01925 6.50972</p> <p>0.0195 6.49195</p> <p>0.01975 6.48078</p> <p>0.02 6.47405</p> <p>0.02025 6.46635</p> <p>0.0205 6.45304</p> <p>0.02075 6.43348</p> <p>0.021 6.40959</p> <p>0.02125 6.38518</p> <p>0.0215 6.36493</p> <p>0.02175 6.35104</p> <p>0.022 6.34095</p> <p>0.02225 6.32964</p> <p>0.0225 6.31313</p> <p>0.02275 6.29039</p> <p>0.023 6.26259</p> <p>0.02325 6.23382</p> <p>0.0235 6.20867</p> <p>0.02375 6.18867</p> <p>0.024 6.17146</p> <p>0.02425 6.15243</p> <p>0.0245 6.12822</p> <p>0.02475 6.09766</p> <p>0.025 6.06206</p> <p>0.02525 6.02536</p> <p>0.0255 5.99144</p> <p>0.02575 5.9613</p> <p>0.026 5.93233</p> <p>0.02625 5.90042</p> <p>0.0265 5.86267</p> <p>0.02675 5.81762</p> <p>0.027 5.76647</p> <p>0.02725 5.71297</p> <p>0.0275 5.66002</p> <p>0.02775 5.60812</p> <p>0.028 5.55564</p> <p>0.02825 5.4997</p> <p>0.0285 5.43621</p> <p>0.02875 5.37507</p> <p>0.029 5.31206</p> <p>0.02925 5.25157</p> <p>0.0295 5.19092</p> <p>0.02975 5.13077</p> <p>0.03 5.07692</p> <p>Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com, Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China</p>
Thermally coupled monolith reactors with enhanced heat transfer for conducting simultaneous endothermic and exothermic reactions
<p><strong>Thermally coupled monolith reactors with enhanced heat transfer for conducting simultaneous endothermic and exothermic reactions</strong></p> <p>Junjie Chen</p> <p>Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China</p> <p>Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com</p> <p> </p> <p>A reactor must be of sufficient length to allow a reaction to proceed to the required conversion. Utilizing high gas velocities typically results in reactors with large length to width ratios which again results in systems with high pressure drops. The smaller the characteristic dimension of the catalyst particle the higher is the utilization of the catalyst. This is sometimes expressed as a higher effectiveness factor. However, beds formed from small particles exhibit higher pressure drops than similar beds formed from larger particle. So, an engineer designs a system with expectable compromises between heat transfer, catalyst utilization, system conversion, and pressure drop. Therefore, a reactor for conducting catalytic processes which can promote overall heat transfer and levels of conversion whilst minimizing pressure drop is desired. Another deficiency of traditional heat transfer equipment is start-up time and thermal response to transients. As reactors are traditionally large and heavy, they have significant thermal inertia. Therefore, the system takes significant time to re-equilibrate from any change in load or process operating conditions. Therefore, a reactor with enhanced response characteristics particularly for rapid start up is desired. A number of methods have been directed to methods of increased heat transfer within reactors and towards low pressure drop catalytic reactors and processes.</p> <p>Streamwise distance (meters), Heat flux (watts per square meter)</p> <p>0 24445.8</p> <p>0.00025 134016</p> <p>0.0005 131072</p> <p>0.00075 151168</p> <p>0.001 85641.3</p> <p>0.00125 -1444</p> <p>0.0015 -1860.19</p> <p>0.00175 -1518.44</p> <p>0.002 54696.4</p> <p>0.00225 97408</p> <p>0.0025 82176</p> <p>0.00275 94848</p> <p>0.003 54951.4</p> <p>0.00325 272.062</p> <p>0.0035 190.062</p> <p>0.00375 172.75</p> <p>0.004 30551.3</p> <p>0.00425 55808</p> <p>0.0045 50432</p> <p>0.00475 60160</p> <p>0.005 35216.3</p> <p>0.00525 267.563</p> <p>0.0055 230.062</p> <p>0.00575 199.562</p> <p>0.006 21724.7</p> <p>0.00625 39680</p> <p>0.0065 35840</p> <p>0.00675 42112</p> <p>0.007 24419.8</p> <p>0.00725 184.875</p> <p>0.0075 157.375</p> <p>0.00775 138</p> <p>0.008 18497.7</p> <p>0.00825 33024</p> <p>0.0085 28672</p> <p>0.00875 32384</p> <p>0.009 18375</p> <p>0.00925 128.25</p> <p>0.0095 103.25</p> <p>0.00975 90.5625</p> <p>0.01 16940.7</p> <p>0.01025 29440</p> <p>0.0105 24448</p> <p>0.01075 26496</p> <p>0.011 14644.3</p> <p>0.01125 91.5</p> <p>0.0115 68.8125</p> <p>0.01175 61.3125</p> <p>0.012 16031.7</p> <p>0.01225 27392</p> <p>0.0125 22016</p> <p>0.01275 23040</p> <p>0.013 12456.8</p> <p>0.01325 69.125</p> <p>0.0135 47.6875</p> <p>0.01375 42.5</p> <p>0.014 15255.2</p> <p>0.01425 25856</p> <p>0.0145 20096</p> <p>0.01475 20224</p> <p>0.015 10784.7</p> <p>0.01525 53.8125</p> <p>0.0155 33.375</p> <p>0.01575 30.25</p> <p>0.016 14481.9</p> <p>0.01625 24192</p> <p>0.0165 18304</p> <p>0.01675 17792</p> <p>0.017 9241.95</p> <p>0.01725 40.7501</p> <p>0.0175 21.3125</p> <p>0.01775 19.5625</p> <p>0.018 13581</p> <p>0.01825 22528</p> <p>0.0185 16768</p> <p>0.01875 15872</p> <p>0.019 8084.96</p> <p>0.01925 31.375</p> <p>0.0195 12.5</p> <p>0.01975 11.3125</p> <p>0.02 12809.2</p> <p>0.02025 20992</p> <p>0.0205 15104</p> <p>0.02075 13824</p> <p>0.021 6927.91</p> <p>0.02125 21.8125</p> <p>0.0215 4.18748</p> <p>0.02175 3.87499</p> <p>0.022 11653.6</p> <p>0.02225 18816</p> <p>0.0225 13312</p> <p>0.02275 12032</p> <p>0.023 5900.31</p> <p>0.02325 15.5625</p> <p>0.0235 -0.375003</p> <p>0.02375 -0.250023</p> <p>0.024 10115.4</p> <p>0.02425 16384</p> <p>0.0245 11520</p> <p>0.02475 10496</p> <p>0.025 5258.69</p> <p>0.02525 13.5625</p> <p>0.0255 0.125008</p> <p>0.02575 -2.83833E-05</p> <p>0.026 8578.74</p> <p>0.02625 13824</p> <p>0.0265 9856</p> <p>0.02675 9216</p> <p>0.027 4618.92</p> <p>0.02725 15.75</p> <p>0.0275 5.68751</p> <p>0.02775 5.625</p> <p>0.028 6404.77</p> <p>0.02825 10624</p> <p>0.0285 8320</p> <p>0.02875 8832</p> <p>0.029 4751.49</p> <p>0.02925 26.8125</p> <p>0.0295 20.3125</p> <p>0.02975 16.3125</p> <p>0.03 2.63005</p> <p>Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com, Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China</p>
Chemical reactors with enhanced heat transfer for conducting simultaneous endothermic and exothermic reactions
<p><strong>Chemical reactors with enhanced heat transfer for conducting simultaneous endothermic and exothermic reactions</strong></p> <p>Junjie Chen</p> <p>Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China</p> <p>Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com</p> <p> </p> <p>Many chemical processes utilize catalysts to enhance chemical conversion behavior. A catalyst promotes the rate of chemical conversion but does not affect the energy transformations which occur during the reaction. Often catalytic processes are conducted within tubes which are packed with a suitable catalytic substance. The process gas flows within the tube and contacts the catalytic packing where reaction proceeds. The tube is placed within a hot environment such as a furnace such that the energy for the process can be supplied through the tube wall via conduction. The mechanism for heat transfer with this arrangement is rather tortuous as heat must first be transferred through the outer boundary layer of the tube, conducted through the often-heavy gauge wall of the tube and then pass through the inner boundary layer into the process gas. The process gas is raised in temperature and this energy can be utilized by the process for chemical reaction. The process engineer is often caused to compromise between the pressure drop within the tube reactor with the overall heat transfer and catalytic effectiveness. The inner heat transfer coefficient can be effectively increased by raising the superficial velocity of the process gas. The higher gas velocity therefore improves the thermal effectiveness of the system. However, higher gas velocities increase the system's pressure drop and results in increased compressor sizes and associated operating costs.</p> <p>Streamwise distance (meters), Heat flux (watts per square meter)</p> <p>0 27306.2</p> <p>0.00025 124496</p> <p>0.0005 117728</p> <p>0.00075 106208</p> <p>0.001 94912</p> <p>0.00125 85088</p> <p>0.0015 76704</p> <p>0.00175 69488</p> <p>0.002 63200</p> <p>0.00225 57712</p> <p>0.0025 52832</p> <p>0.00275 48528</p> <p>0.003 44704</p> <p>0.00325 41264</p> <p>0.0035 38144</p> <p>0.00375 35344</p> <p>0.004 32912</p> <p>0.00425 30720</p> <p>0.0045 28688</p> <p>0.00475 26832</p> <p>0.005 25184</p> <p>0.00525 23664</p> <p>0.0055 22272</p> <p>0.00575 21056</p> <p>0.006 19952</p> <p>0.00625 18912</p> <p>0.0065 17936</p> <p>0.00675 17072</p> <p>0.007 16288</p> <p>0.00725 15568</p> <p>0.0075 14864</p> <p>0.00775 14240</p> <p>0.008 13728</p> <p>0.00825 13216</p> <p>0.0085 12752</p> <p>0.00875 12304</p> <p>0.009 11840</p> <p>0.00925 11472</p> <p>0.0095 11168</p> <p>0.00975 10832</p> <p>0.01 10448</p> <p>0.01025 10128</p> <p>0.0105 9952</p> <p>0.01075 9776</p> <p>0.011 9472</p> <p>0.01125 9232</p> <p>0.0115 9136</p> <p>0.01175 8832</p> <p>0.012 8640</p> <p>0.01225 8688</p> <p>0.0125 8576</p> <p>0.01275 8432</p> <p>0.013 8320</p> <p>0.01325 8192</p> <p>0.0135 8016</p> <p>0.01375 7904</p> <p>0.014 7840</p> <p>0.01425 7728</p> <p>0.0145 7648</p> <p>0.01475 7552</p> <p>0.015 7488</p> <p>0.01525 7440</p> <p>0.0155 7360</p> <p>0.01575 7312</p> <p>0.016 7248</p> <p>0.01625 7184</p> <p>0.0165 7104</p> <p>0.01675 7024</p> <p>0.017 6992</p> <p>0.01725 7008</p> <p>0.0175 7008</p> <p>0.01775 6928</p> <p>0.018 6880</p> <p>0.01825 6880</p> <p>0.0185 6800</p> <p>0.01875 6720</p> <p>0.019 6720</p> <p>0.01925 6704</p> <p>0.0195 6640</p> <p>0.01975 6592</p> <p>0.02 6624</p> <p>0.02025 6592</p> <p>0.0205 6496</p> <p>0.02075 6464</p> <p>0.021 6512</p> <p>0.02125 6528</p> <p>0.0215 6448</p> <p>0.02175 6384</p> <p>0.022 6384</p> <p>0.02225 6320</p> <p>0.0225 6272</p> <p>0.02275 6288</p> <p>0.023 6272</p> <p>0.02325 6240</p> <p>0.0235 6192</p> <p>0.02375 6224</p> <p>0.024 6224</p> <p>0.02425 6160</p> <p>0.0245 6112</p> <p>0.02475 6112</p> <p>0.025 6080</p> <p>0.02525 5984</p> <p>0.0255 5968</p> <p>0.02575 6016</p> <p>0.026 6016</p> <p>0.02625 5936</p> <p>0.0265 5888</p> <p>0.02675 5904</p> <p>0.027 5888</p> <p>0.02725 5824</p> <p>0.0275 5776</p> <p>0.02775 5760</p> <p>0.028 5696</p> <p>0.02825 5568</p> <p>0.0285 5552</p> <p>0.02875 5584</p> <p>0.029 5472</p> <p>0.02925 5344</p> <p>0.0295 5280</p> <p>0.02975 5280</p> <p>0.03 5280</p> <p>Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com, Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China</p>
Combined heat exchanger reactors for conducting simultaneous endothermic and exothermic reactions
<p><strong>Combined heat exchanger reactors for conducting simultaneous endothermic and exothermic reactions</strong></p> <p>Junjie Chen</p> <p>Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China</p> <p>Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com</p> <p> </p> <p>It has been described a process to generate a hydrogen rich gas by generating a catalytic film which is composed of layers of different catalysts. It is proposed that steam reforming of a hydrocarbon be performed by one layer and the energy for this process be supplied by a hydrocarbon oxidative process being promoted in the subsequent layer. Various hybrids of this theme are proposed. However, as the heat is supplied by an autothermal reaction, oxygen must be supplied along with the fuel stream. As well as the oxygen, associated nitrogen is present. This nitrogen acts to absorb process energy which lowers the thermal efficiency of the process as well as diluting the desired product, hydrogen. The presence of the nitrogen increases the load on downstream partial oxidation units which act to oxidize carbon monoxide to carbon dioxide. The nitrogen also reduces the streams suitability for use in fuel cells. Therefore, a reactor which can supply sufficient energy to an endothermic reaction without mixing the streams is needed. It has been described a method where parallel and discrete channels can be formed by stacking suitable plates to form a structure. The plates are then bonded together using brazing, welding or diffusion bonding techniques. It is also claimed that cast ceramic plates can be used with a suitable sealing mechanism. Catalyst can be adhered onto the wall and energy supplied or removed via conduction between subsequent channels. However, the design does not allow for catalyst replenishment nor precious metal recovery. Therefore, a reactor which affords an easy and cheap method for catalyst replacement and replenishment is required.</p> <p>Streamwise distance (meters), Heat flux (watts per square meter)</p> <p>0 28543.2</p> <p>0.00025 147840</p> <p>0.0005 130560</p> <p>0.00075 136832</p> <p>0.001 76061.5</p> <p>0.00125 4012.44</p> <p>0.0015 6787.19</p> <p>0.00175 9091.13</p> <p>0.002 70670.9</p> <p>0.00225 107776</p> <p>0.0025 78720</p> <p>0.00275 75904</p> <p>0.003 39811.2</p> <p>0.00325 1654.75</p> <p>0.0035 2917.25</p> <p>0.00375 4164.75</p> <p>0.004 50131</p> <p>0.00425 77568</p> <p>0.0045 55552</p> <p>0.00475 53248</p> <p>0.005 27844.7</p> <p>0.00525 1018.19</p> <p>0.0055 1766.44</p> <p>0.00575 2553.25</p> <p>0.006 36808.2</p> <p>0.00625 58240</p> <p>0.0065 43264</p> <p>0.00675 43136</p> <p>0.007 23029</p> <p>0.00725 728.5</p> <p>0.0075 1212.56</p> <p>0.00775 1734.25</p> <p>0.008 27885.2</p> <p>0.00825 45056</p> <p>0.0085 34944</p> <p>0.00875 37120</p> <p>0.009 20554</p> <p>0.00925 566.687</p> <p>0.0095 893.187</p> <p>0.00975 1261.12</p> <p>0.01 22236.7</p> <p>0.01025 36992</p> <p>0.0105 30464</p> <p>0.01075 33920</p> <p>0.011 19118</p> <p>0.01125 463.125</p> <p>0.0115 683.938</p> <p>0.01175 966.625</p> <p>0.012 18747.8</p> <p>0.01225 31872</p> <p>0.0125 27136</p> <p>0.01275 31232</p> <p>0.013 17946</p> <p>0.01325 392.437</p> <p>0.0135 547.312</p> <p>0.01375 772.062</p> <p>0.014 16463.2</p> <p>0.01425 28544</p> <p>0.0145 25088</p> <p>0.01475 29568</p> <p>0.015 17164.1</p> <p>0.01525 343.563</p> <p>0.0155 452.563</p> <p>0.01575 637.126</p> <p>0.016 14980</p> <p>0.01625 26240</p> <p>0.0165 23296</p> <p>0.01675 27776</p> <p>0.017 16257.6</p> <p>0.01725 307.437</p> <p>0.0175 385.437</p> <p>0.01775 541.563</p> <p>0.018 13518</p> <p>0.01825 24064</p> <p>0.0185 21888</p> <p>0.01875 26240</p> <p>0.019 15353.1</p> <p>0.01925 280.813</p> <p>0.0195 340.375</p> <p>0.01975 476.688</p> <p>0.02 12456</p> <p>0.02025 22144</p> <p>0.0205 20352</p> <p>0.02075 24832</p> <p>0.021 14579.9</p> <p>0.02125 263.812</p> <p>0.0215 312.5</p> <p>0.02175 433.625</p> <p>0.022 11277.1</p> <p>0.02225 20480</p> <p>0.0225 19072</p> <p>0.02275 23296</p> <p>0.023 13807.9</p> <p>0.02325 251.563</p> <p>0.0235 294.875</p> <p>0.02375 404.437</p> <p>0.024 10105.3</p> <p>0.02425 18432</p> <p>0.0245 17152</p> <p>0.02475 20864</p> <p>0.025 12394.4</p> <p>0.02525 236.813</p> <p>0.0255 276.937</p> <p>0.02575 375.75</p> <p>0.026 8677.24</p> <p>0.02625 15744</p> <p>0.0265 14592</p> <p>0.02675 17792</p> <p>0.027 10592.6</p> <p>0.02725 213.125</p> <p>0.0275 249.625</p> <p>0.02775 335.938</p> <p>0.028 7370.84</p> <p>0.02825 13184</p> <p>0.0285 11648</p> <p>0.02875 13312</p> <p>0.029 7754.35</p> <p>0.02925 167.812</p> <p>0.0295 212.062</p> <p>0.02975 190.063</p> <p>0.03 25.6936</p> <p>Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com, Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China</p>
Catalytic reactors with enhanced chemical conversion behavior for conducting simultaneous endothermic and exothermic reactions
<p><strong>Catalytic reactors with enhanced chemical conversion behavior for conducting simultaneous endothermic and exothermic reactions</strong></p> <p>Junjie Chen</p> <p>Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China</p> <p>Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com</p> <p> </p> <p>It has been taught methods which may be used to transform a monolithic structure into a co-current or countercurrent flow heat exchanger. The monolith is transformed by cutting or grinding the uppermost section of diving walls from rows of channels contained in the honeycomb. The top end of the newly formed groove is then sealed with suitable cement. The depth of the sealant is such that an opening still exists in the side wall of the structure. A manifold is attached to this inlet. A similar exercise is performed at the opposing end to produce an outlet section. Hot gas is passed through the inlet whilst cold coolant is passed through the open end. Efficient heat transfer occurs between the two streams. However, the possibility of using such an arrangement for coupling endothermic and exothermic catalytic processes on opposing sides of each dividing wall is not taught. It has been taught a method to efficiently transfer energy through a divider by contacting a catalyst to the wall and performing an exothermic reaction there. The energy is conducted through the wall and used to heat a gas stream on the opposing side of the wall. An apparatus is described where multiple layers are formed with alternating hot and cold channels to produce a gas heater. However, the method does not discuss the possibility of utilizing this concept for thermally coupling endothermic and exothermic reactions within a monolith reactor.</p> <p>Streamwise distance (meter), Heterogeneous reaction rate along the length of the reactor (mole per square meter per second)</p> <p>0 1.88478</p> <p>0.00025 1.92635</p> <p>0.0005 2.0243</p> <p>0.00075 2.14121</p> <p>0.001 2.26285</p> <p>0.00125 2.38391</p> <p>0.0015 2.5016</p> <p>0.00175 2.61386</p> <p>0.002 2.71933</p> <p>0.00225 2.81695</p> <p>0.0025 2.9061</p> <p>0.00275 2.98659</p> <p>0.003 3.05831</p> <p>0.00325 3.12146</p> <p>0.0035 3.17647</p> <p>0.00375 3.22385</p> <p>0.004 3.26403</p> <p>0.00425 3.29778</p> <p>0.0045 3.32579</p> <p>0.00475 3.34828</p> <p>0.005 3.36585</p> <p>0.00525 3.37923</p> <p>0.0055 3.38901</p> <p>0.00575 3.39569</p> <p>0.006 3.39964</p> <p>0.00625 3.40142</p> <p>0.0065 3.40139</p> <p>0.00675 3.39974</p> <p>0.007 3.39685</p> <p>0.00725 3.39304</p> <p>0.0075 3.38846</p> <p>0.00775 3.38332</p> <p>0.008 3.37786</p> <p>0.00825 3.37216</p> <p>0.0085 3.36657</p> <p>0.00875 3.36135</p> <p>0.009 3.35646</p> <p>0.00925 3.35185</p> <p>0.0095 3.34767</p> <p>0.00975 3.34403</p> <p>0.01 3.3408</p> <p>0.01025 3.33803</p> <p>0.0105 3.33572</p> <p>0.01075 3.33405</p> <p>0.011 3.33301</p> <p>0.01125 3.33242</p> <p>0.0115 3.33227</p> <p>0.01175 3.33256</p> <p>0.012 3.33329</p> <p>0.01225 3.33451</p> <p>0.0125 3.33619</p> <p>0.01275 3.33825</p> <p>0.013 3.34069</p> <p>0.01325 3.34347</p> <p>0.0135 3.34647</p> <p>0.01375 3.34978</p> <p>0.014 3.35347</p> <p>0.01425 3.35729</p> <p>0.0145 3.36123</p> <p>0.01475 3.36531</p> <p>0.015 3.36946</p> <p>0.01525 3.37365</p> <p>0.0155 3.37777</p> <p>0.01575 3.38195</p> <p>0.016 3.38636</p> <p>0.01625 3.39101</p> <p>0.0165 3.3956</p> <p>0.01675 3.40005</p> <p>0.017 3.40456</p> <p>0.01725 3.40915</p> <p>0.0175 3.41362</p> <p>0.01775 3.41806</p> <p>0.018 3.42267</p> <p>0.01825 3.42714</p> <p>0.0185 3.43145</p> <p>0.01875 3.43582</p> <p>0.019 3.44022</p> <p>0.01925 3.44451</p> <p>0.0195 3.44872</p> <p>0.01975 3.45302</p> <p>0.02 3.45739</p> <p>0.02025 3.46153</p> <p>0.0205 3.46548</p> <p>0.02075 3.4695</p> <p>0.021 3.47355</p> <p>0.02125 3.47744</p> <p>0.0215 3.4811</p> <p>0.02175 3.48467</p> <p>0.022 3.48808</p> <p>0.02225 3.49137</p> <p>0.0225 3.49463</p> <p>0.02275 3.49784</p> <p>0.023 3.50085</p> <p>0.02325 3.50358</p> <p>0.0235 3.50617</p> <p>0.02375 3.50872</p> <p>0.024 3.51116</p> <p>0.02425 3.51353</p> <p>0.0245 3.51592</p> <p>0.02475 3.51817</p> <p>0.025 3.52004</p> <p>0.02525 3.52161</p> <p>0.0255 3.52305</p> <p>0.02575 3.52439</p> <p>0.026 3.52547</p> <p>0.02625 3.52614</p> <p>0.0265 3.52658</p> <p>0.02675 3.5265</p> <p>0.027 3.52593</p> <p>0.02725 3.5252</p> <p>0.0275 3.52428</p> <p>0.02775 3.52285</p> <p>0.028 3.52091</p> <p>0.02825 3.51866</p> <p>0.0285 3.51596</p> <p>0.02875 3.51277</p> <p>0.029 3.50899</p> <p>0.02925 3.5048</p> <p>0.0295 3.4992</p> <p>0.02975 3.4806</p> <p>0.03 3.46548</p> <p>Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com, Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China</p>
Microchannel steam reforming reactors with enhanced heat transfer for conducting simultaneous endothermic and exothermic reactions
<p><strong>Microchannel steam reforming reactors with enhanced heat transfer for conducting simultaneous endothermic and exothermic reactions</strong></p> <p>Junjie Chen</p> <p>Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China</p> <p>Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com</p> <p> </p> <p>It has been described a compact multiple tube steam reformer. The design consists of multiple packed tubes, of small diameter, being placed in intimate contact with a heat generating flame. The arrangement leads to improved heat transfer and therefore chemical conversion. However, the packed tube results in a significant pressure drop and the author states the process is still heat transfer limited. Therefore, a reactor design which minimizes the process side pressure drop and does not suffer from heat transfer limitation is required. It has been described a method to modify a monolithic structure into a combined heat exchanger reactor. The method describes the mechanical process to transform the structure into a structure consisting of two discrete volumes. It is proposed that the arrangement can either be used as a heat exchanger, where energy is transferred from one stream to another via conduction through the wall or it is suitable as a chemical reactor where the second set of channels allow the introduction of a heat transfer fluid. In the second case, the energy required or generated through the reaction is removed via a heat transfer fluid in the second channel. It is noted that the reaction can be a catalytic process and the catalytically active material can be coated onto the monolith passage walls to minimize pressure drop. In this arrangement, the heat transfer from the process catalyst to the dividing wall will be highly efficient, however, the uptake of the energy by the heat transfer fluid will suffer from all of the limitations of traditional heat transfer operations. In this case, the boundary layer will provide a significant resistance to heat transfer and will severely limit the rate of the process. Also, for this arrangement to successfully supply or remove heat and maintain a near isothermal longitudinal profile considerable heat transfer fluid velocities must be utilized. The high velocities will reduce the characteristic thickness of the boundary layer and ensure that a sufficient mass of heat transfer fluid is available to absorb the heat of reaction without significantly changing temperature. These requirements will lead to excessive pressure drop through the coolant channels. Therefore, a reactor design which minimizes the heat transfer fluid side pressure drop is required. The method does not teach about combining endothermic and exothermic reactions on opposing sides of dividing walls of adjacent channels as an efficient method of heat transfer.</p> <p>Streamwise distance (meters), Heat flux (watts per square meter)</p> <p>0 28082.8</p> <p>0.00025 139648</p> <p>0.0005 111616</p> <p>0.00075 93312</p> <p>0.001 81920</p> <p>0.00125 74112</p> <p>0.0015 68096</p> <p>0.00175 62976</p> <p>0.002 58752</p> <p>0.00225 55168</p> <p>0.0025 52096</p> <p>0.00275 49152</p> <p>0.003 46336</p> <p>0.00325 44032</p> <p>0.0035 41984</p> <p>0.00375 40064</p> <p>0.004 38400</p> <p>0.00425 36864</p> <p>0.0045 35328</p> <p>0.00475 33920</p> <p>0.005 32512</p> <p>0.00525 31360</p> <p>0.0055 30336</p> <p>0.00575 29184</p> <p>0.006 28288</p> <p>0.00625 27392</p> <p>0.0065 26496</p> <p>0.00675 25728</p> <p>0.007 24832</p> <p>0.00725 24192</p> <p>0.0075 23680</p> <p>0.00775 23040</p> <p>0.008 22400</p> <p>0.00825 21760</p> <p>0.0085 21376</p> <p>0.00875 21120</p> <p>0.009 20608</p> <p>0.00925 20224</p> <p>0.0095 19968</p> <p>0.00975 19456</p> <p>0.01 19072</p> <p>0.01025 18688</p> <p>0.0105 18432</p> <p>0.01075 18176</p> <p>0.011 17920</p> <p>0.01125 17792</p> <p>0.0115 17536</p> <p>0.01175 17280</p> <p>0.012 17024</p> <p>0.01225 16768</p> <p>0.0125 16640</p> <p>0.01275 16512</p> <p>0.013 16384</p> <p>0.01325 16256</p> <p>0.0135 16128</p> <p>0.01375 16000</p> <p>0.014 15872</p> <p>0.01425 15744</p> <p>0.0145 15488</p> <p>0.01475 15488</p> <p>0.015 15360</p> <p>0.01525 15104</p> <p>0.0155 15104</p> <p>0.01575 14976</p> <p>0.016 14848</p> <p>0.01625 14720</p> <p>0.0165 14720</p> <p>0.01675 14720</p> <p>0.017 14592</p> <p>0.01725 14336</p> <p>0.0175 14336</p> <p>0.01775 14464</p> <p>0.018 14336</p> <p>0.01825 14336</p> <p>0.0185 14336</p> <p>0.01875 14208</p> <p>0.019 14080</p> <p>0.01925 14080</p> <p>0.0195 14080</p> <p>0.01975 14080</p> <p>0.02 13952</p> <p>0.02025 13824</p> <p>0.0205 13824</p> <p>0.02075 13952</p> <p>0.021 13952</p> <p>0.02125 13824</p> <p>0.0215 13696</p> <p>0.02175 13568</p> <p>0.022 13568</p> <p>0.02225 13696</p> <p>0.0225 13696</p> <p>0.02275 13440</p> <p>0.023 13312</p> <p>0.02325 13440</p> <p>0.0235 13440</p> <p>0.02375 13312</p> <p>0.024 13312</p> <p>0.02425 13312</p> <p>0.0245 13312</p> <p>0.02475 13184</p> <p>0.025 13056</p> <p>0.02525 13056</p> <p>0.0255 13056</p> <p>0.02575 12800</p> <p>0.026 12672</p> <p>0.02625 12800</p> <p>0.0265 12672</p> <p>0.02675 12544</p> <p>0.027 12544</p> <p>0.02725 12288</p> <p>0.0275 12160</p> <p>0.02775 12160</p> <p>0.028 12032</p> <p>0.02825 12032</p> <p>0.0285 11904</p> <p>0.02875 11776</p> <p>0.029 11648</p> <p>0.02925 11520</p> <p>0.0295 11392</p> <p>0.02975 11008</p> <p>0.03 10624</p> <p>Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: komcjj@gmail.com, Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China</p>
Water loss, not overheating, limits the activity period of an endothermic Sonoran Desert bee
<ol> <li>Desert animals must manage the physiological stresses of heat and desiccation; evaporative heat loss mitigates overheating but exacerbates water stress. Small endothermic flying insects may be particularly vulnerable to overheating and water stress as a result of high surface area to volume ratios, but we lack quantitative understanding of the relative magnitude of these abiotic stressors in flying desert invertebrates, despite their ecological importance.</li> <li>During the hottest and driest weeks of the year, many thousands of males of the Sonoran Desert digger bee (<em>Centris</em> <em>caesalpiniae</em>) flew near-continuously at elevated thorax temperatures for hours at mating aggregation sites, while occasionally fighting other males and digging for females.</li> <li>To determine whether incapacitating high temperatures or water loss limited the activity period of male <em>C. caesalpiniae</em>, we assessed wet and dry body mass and water content through the activity period, crop volume and sugar content, microclimate selection, water loss rate and metabolic water production during flight, critical water content, and maximum critical temperature.</li> <li>Body masses and sizes of males declined through the morning and smaller bees had higher fractional water contents. Crop volume and sugar content did not vary through the day or with bee size.</li> <li>Maximum critical temperature during flight was 51°C, similar to those measured for other bees, and well above temperatures reached in the field, suggesting that avoidance of over-heating does not limit activity in this desert bee.</li> <li>The critical water content of <em>Centris</em> bees averaged 50%. Measures of net water loss rate indicated that males approached lethal water loss limits within four hours, suggesting that desiccation tolerance limits activity. Remarkably, male <em>C. caesalpiniae </em>were not observed to forage at floral or water sources during the activity period, and foraged over multiple days, suggesting selection to maintain reproductive success and that these males have a mechanism to rehydrate when not at the mating aggregation.</li> </ol>
Water loss, not overheating, limits the activity period of an endothermic Sonoran Desert bee
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The thermal performance curve for aerobic metabolism of a flying endotherm
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Data from: Endothermic mosasaurs? Possible thermoregulation of Late Cretaceous mosasaurs (Reptilia, Squamata) indicated by stable oxygen isotopes in fossil bioapatite in comparison with coeval marine fish and pelagic seabirds
The thermoregulatory style of Late Cretaceous mosasaurs has become a highly controversial subject in vertebrate palaeontology. These extinct marine reptiles have previously been described as poikilothermic, endothermic or gigantothermic. Here we analyse three genera of mosasaurs from the Mooreville Chalk in Alabama (USA) of differing body mass, and compare their δ18OPO4 derived body temperatures (Tb) with those of coeval poikilothermic fish (Enchodus) and endothermic pelagic seabirds (Ichthyornis). Results show that all mosasaurs, Clidastes (Tb = 33.1°C), Platecarpus (Tb = 36.3°C), and Tylosaurus (Tb = 34.3°C), had elevated average body temperatures in relation to those of the fish (Tb = 28.3°C) and were closer to those of Ichthyornis (Tb = 38.6°C). The temperatures calculated for Enchodus compare well with previously reported temperature estimates for the Mooreville Chalk and the Tb of Ichthyornis compares well with temperatures that have been reported for modern seabirds, suggesting that this method provides accurate results. Finally, although there are small differences of body temperature among mosasaur genera, these are independent of size, and thus inferred body mass, suggesting that mosasaurs were not gigantotherms, but rather endotherms.
Data for: An alternative hypothesis for the evolution of sexual segregation in endotherms
<p><span><b>Aim: </b>Patterns of separation among males and females, known as sexual segregation, traditionally correlate with elevation or latitude in animals. <span>Alternatively, in humans, spatial and behavioural segregation are driven by inherent sex-based differences in thermal preference, although their cause and adaptive value of these differences remain unclear. Here, we </span>explore whether<span>, similar to humans, </span>ambient temperature can explain patterns of separation among males and females <span>in endotherms. </span></span></p> <p><span><b>Location: </b>Israel.</span></p> <p><span><b>Time period: </b>1981 – 2018.</span></p> <p><span><b>Major taxa studied: </b>Migratory sexually dimorphic birds (13 species) and bats (18 species).</span></p> <p><span><b>Methods: </b>We calculated the proportion of males and females at each sampling site for each bird or bat species. We used general linear mixed models (GLMM) to quantify the variance explained by elevation, latitude, body size and ambient temperature, and corrected for phylogeny, site and year. We employed model averaging over the best models by comparing corrected Akaike information criterion.</span></p> <p><span><b>Results: </b>We found a correlation between geographic separation and temperature that accounts for variance in the data that is not explained by elevation and latitude. We show that temperature was negatively correlated with the proportion of males in bats and birds, whereas body size only explained this response in birds.</span></p> <p><span><b>Main conclusions: </b><a>Our findings suggest that females are found in higher ambient temperatures. </a>We term this Differential Sex-related Thermal Preference (DSTP) and propose that it is a broad phenomenon common in many endotherms, acting as a significant force shaping dispersal, sociality, and behaviour of animals and should be explored from this wide perspective.</span></p>
FIGURE 2. A in Oology And The Evolution Of Thermophysiology In Saurischian Dinosaurs: Homeotherm And Endotherm Deinonychosaurians?
FIGURE 2. A. Incubating troodontid in a desert/semi-desert environment in Asia (rendered by artist Doyle Trankina). Note the position of the incubating parent on the egg clutch as its axial skeleton rests on the vertically/sub-vertically orientated eggs, a position that contrasts with that of oviraptorids where mostly their appendicular skeleton covers the clutch. Furthermore, there is no space without eggs in the clutch center as observed in oviraptorids and unidentified Chinese Macroolithid egg clutches. B. Partial troodontid egg clutch from China (LX09XLOZLX0001-2156). Although not associated with any skeletal remains, taxonomic identification was supported by the eggshell microstructure and egg morphology.Note that the asymmetric shape of these eggs due to the presence of a well developed air cell (arrows) and that the pointed pole faces down with the eggs buried nearly up to the level of the location of the air cell (doted lines). C. SEM of eggshell spared from the region indicated by the white rectangle. Note the presence of two prismatic layers, here separated by a dotted lines, with layer 1 consisting of blade-shaped calcite crystals.
FIGURE 1 in Oology And The Evolution Of Thermophysiology In Saurischian Dinosaurs: Homeotherm And Endotherm Deinonychosaurians?
FIGURE 1. Cladogram inspired from Clark et al., 2002 and Buffetaut et al., 2005, and oological analyses from Grellet-Tinner et al., (2006) and Grellet-Tinner and Makovicky (in press). Note the coeveal appearance of a change in the architecture of the nest, egg shape, and eggshell structure namely in oviraptorids and at the level of troodontids. All these evolutionary transformation reflect a change of thermophysiology, interpreted as an avian-like endothermy in troodontids. Letters indicate the appearance of synapomorphies and when followed by a negative sign indicate a reversal (homoplasy). The optimization of several of these characters is putative and likely to change when more taxa are described in the future. Node 1- Sauropoda; Node 2- Maniraptora; Node 3- Paraves; Node 4- Avialae; Node 5- Ornithothoraces; Node 6- Neornithines Clade 1- Titanosauria;Clade 2- Oviraptorosauria; Clade 3- Troodontidae; Clade 4- Dromaeosauridae; Clade 5- an unidentified coelurosaurid from Phu Phok; Clade 6- possible enantiornithine from Néuquen; Clade 7- Neognathae; Clade 8- Paleognathae Characters a. Presence of surficial ornamentation; b. Acicular crystals as building blocks of the eggshell structure; c. Eggs contained within a rimed nest; d. Nodular ornamentation in titanosaurids; e. Presence of two and aprismatic layers; f. Acicular crystals limited to layer 1; g. Linear ornamentation; h. Elongated eggs; i. Presence of a small-air cell; j. Monoautochronic ovideposition as indicated by the eggs arranged in pairs; k. Eggs are laid on the perimeters of circles that superposed in 2-3 layers and with an empty space in the center of the clutch; l. Presence of brooding behavior; m. Differentiation of organic lines within layer 2; n. Presence of blade-shaped crystals in layer 1; o. Presence of a single circle of eggs; p. Presence of a fully developed air cell; q. No space devoid of eggs in the center of the clutch; r. Reduction from two to one functioning ovary; s. Presence of two and prismatic eggshell structural layers; t. Eggs are vertically oriented in the substrate with air cell up; u. Absence of eggshell surficial ornamentation; v. Presence of bi-modial nodular ornamentation; x. Presence of three prismatic eggshell structural layers; y. Layer 1 wider than layer 2.
Fig. 3 in Comparative thermoregulation of sympatric endothermic and ectothermic cicadas (Homoptera: Cicadidae: Tibicen winnemanna and Tibicen chloromerus )
Fig. 3 Distribution of T. winnemanna Tb as a function of Ta for animals classified as ''inactive'' during the evening chorus (solid line, open circles, y ˆ 12.04 + 0.620x, r ˆ 0.834) and the Tbs of T. winnemanna after the species' evening activity period (dashed line, filled circles, y ˆ 15.73+0.435x, r ˆ 0.657). Although the slope of the regression for ''inactive'' animals is significantly dierent from one (t ˆ)3.20, df ˆ 12, P ˆ 0.0038), twoanimals hadbody temperatures equal to ambient temperature. Mean Tbs and the temperature gradient of ''inactive'' animals is significantly lower than ''active'' (soundproducing) animals (see text). The slope of the linear regression after activity is not significantly dierent from one, showing that T. winnemanna becomes a thermoconformer during the night (t ˆ)1.603, df ˆ 2, P ˆ 0.1251)
Fig. 2 in Comparative thermoregulation of sympatric endothermic and ectothermic cicadas (Homoptera: Cicadidae: Tibicen winnemanna and Tibicen chloromerus )
Fig. 2 Evening Tb distribution of T. chloromerus (solid line, filled circles, y ˆ 9.47 + 0.708x, r ˆ 0.761) and body temperature as a function of Ta in T. winnemanna (dashed line, open circles, y ˆ 16.34 + 0.618x, r ˆ 0.695) producing sound (''active'' animals) during the species' normal evening activity period. The slope of the regression for T. chloromerus is not significantly dierent than one, indicating that the species is a thermoconformer during the evening (t ˆ)9.673, df ˆ 4, P ˆ 0.1941). The slope of the regression for T. winnemanna is significantly dierent than one, indicating that T. winnemanna regulates Tb without access to solar radiation (t ˆ)5.736, df ˆ 92, P 0:00001)
Fig. 1 in Comparative thermoregulation of sympatric endothermic and ectothermic cicadas (Homoptera: Cicadidae: Tibicen winnemanna and Tibicen chloromerus )
Fig. 1 Diurnal body temperature (Tb) of Tibicen chloromerus (solid line, filled circles, y ˆ 31.35 + 0.202x, r ˆ 0.217) and T. winnemanna (dashed line, open circles, y ˆ 18.70 + 0.498x, r ˆ 0.619) as a function of ambient temperature (Ta). The slope of the linear regression is significantly dierent from one, suggesting thermoregulation (t ˆ)5.739, df ˆ 21, P <0.00001) for T. chloromerus and (t ˆ)2.509, df ˆ 10, P <0.02) for T. winnemanna
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