standard heat
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2022 ◽  
Vol 5 (1) ◽  
pp. 1-7
Author(s):  
Asmaa J.i AL-Lame ◽  
Wafaa F. Rodhan ◽  
Nafeesa J. Kadhim ◽  
Shahed K. Taher

The standard heat of formation (ΔHof) and binding energy (ΔEb) for the free compound and their derivatives are calculated by using the PM3 method at 273K of Hyperchem.-8.07 program. The compound is more stable than their derivatives. furthermore to investigate the reactive site of the molecules the electrostatic potential of free derivatives is measured and pm3 is used to evaluate the vibrational spectra of the free derivatives, the frequencies are obtained approximately agreed with those values experimentally found; in addition, the calculation helps to assign clearly the most diagnostic bands .


2022 ◽  
Vol 5 (1) ◽  
pp. 1-15
Author(s):  
Giacomo Ascione ◽  
◽  
Daniele Castorina ◽  
Giovanni Catino ◽  
Carlo Mantegazza ◽  
...  

<abstract><p>We derive a matrix version of Li &amp; Yau–type estimates for positive solutions of semilinear heat equations on Riemannian manifolds with nonnegative sectional curvatures and parallel Ricci tensor, similarly to what R. Hamilton did in <sup>[<xref ref-type="bibr" rid="b5">5</xref>]</sup> for the standard heat equation. We then apply these estimates to obtain some Harnack–type inequalities, which give local bounds on the solutions in terms of the geometric quantities involved.</p></abstract>


2021 ◽  
Vol 9 (10) ◽  
pp. 1167-1176
Author(s):  
Omer Beganovic ◽  

The creep of the pre-strained superalloy N07080 is described in this work. The pre-strain was achieved by warm rolling at 1050 oC.-The warm rolling was performed due to additional strengthening, i.e increasing of the superalloy hardness.-The pre-strain drastically reduces the creep rupture life of the superalloy compared to the creep rupture life of the standard heat treated superalloy.-The drastic reductionof the creep rupture life is result of rapid creep cavity nucleation on stress concentration sites along primary grain boundaries of the pre-strained superalloy.-Recrystallization eliminates potential sites for rapid cavity nucleation and prolongates the creep rupture life.


Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1196
Author(s):  
Juan Carlos Pereira ◽  
Jon Aranzabe ◽  
Mari Carmen Taboada ◽  
Noelia Ruiz ◽  
Pedro Pablo Rodriguez

In this work, new customized heat treatments for selective laser melted (SLM) parts in IN718 alloy were analyzed. This was done through the evaluation of the mechanical properties and advanced characterization of the phases and microstructure obtained in as-built condition and after the application of standard and tailored heat treatments. The microstructure and mechanical properties were compared and discussed with results reported in the literature. Finally, strengthening mechanisms of IN718 alloy processed by SLM and its differences with mechanisms that occur in investment casting were analyzed. Both processes generate quite different microstructures, investment casting is composed mainly by a dendritic structure, and SLM is characterized by columnar and cellular structures with very thin cells. Due to the fine and homogeneous microstructure obtained from SLM processing and its specific strengthening mechanisms, it is not necessary to apply homogenization and solution stages as in standard heat treatment used for this type of alloy in casting or wrought. The pre-heating and process parameters selected, in combination with a direct stepped aging (at 720 °C/620 °C), provide the material with its best mechanical properties, which are superior to those obtained by standard heat treatment (AMS 5383F) applied to investment casting of IN718 alloy.


Author(s):  
Samuel Lorin ◽  
Julia Madrid ◽  
Rikard Söderberg ◽  
Kristina Wärmefjord

Abstract Laser welding is a common technique for joining metals in many manufacturing industries. Due to the heat input and the resulting melting and solidification, the parts deform causing residual distortion and residual stresses. To assure the geometrical and functional quality of the product, Computational Welding Mechanics (CWM) is often employed in the design phase to predict the outcome of different design proposals. Furthermore, CWM can be used to design the welding process with the objective of assuring the quality of the weld. However, welding is a complex multi-physical process and in a design process it is typically not feasible, for example, to employ fluid simulation of the weld pool in order to predict deformation, especially if a set of design proposals is under investigation. Instead, what is used is a heat source that emulates the heat input from the melt pool. However, standard heat sources are typically not flexible enough to capture the fusion zone for deep keyhole mode laser welding. In this paper, a new heat source model for keyhole mode laser welding is presented. In an industrial case study, a number of bead on plate welds have been employed to compare standard weld heat sources and develop the new heat source model. The proposed heat source is based on a combination of standard heat sources. From the study, it was concluded that the standard heat sources could not predict the observed melted zone for certain industrial application while the new heat source was able to do so.


2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 4-5
Author(s):  
Heath Harper ◽  
Gustavo Silva ◽  
Beau A Peterson ◽  
Joe Connor ◽  
Amos Petersen ◽  
...  

Abstract The objectives were to evaluate differences in productivity (mortality, number of pigs weaned and litter weights) and electricity usage between farrowing crates equipped with the HAVEN device or standard heat lamps. The HAVEN is a heat element designed to create a microclimate for newborn pigs. A total of 314 sows (Camborough; PIC, Hendersonville, TN) were initially allotted to the study in a randomized complete block design (RCBD) based on parity (P1, P2, P3+). Treatments consisted of control group (standard heat lamps) and treatment group (HAVEN device). Around d112 of gestation the sows were moved to the farrowing house and randomly allotted to the treatment. After farrow, litters were cross-fostered within treatment until 24-h after farrowing to equalize litter number to teat count. Litter size and weight were collected at the time of cross-fostering and at weaning. Sows had an ad libitum access to feed and water during lactation. Data were analyzed as an RCBD using the GLIMMIX procedure of SAS with litter as the experimental unit and block as a random effect. There was no significant difference (P &gt; 0.05) between treatments on litter growth performance. However, there were significant differences (P &lt; 0.05) between the Control and Haven groups on piglets mortality and removals (%). The Control group had a higher incidence of mortality when compared to the Haven group (11.42% vs. 9.06%, respectively). In addition, the Control group had a higher (P &lt; 0.05) percentage of pigs removed compared to the Haven group (18.41% vs. 15.55%, respectively). Regarding electricity usage, on average the HAVEN device consumed 1.55 Wh/day compared to 2.41 Wh/day from the heat lamp. In conclusion, under the conditions of this trial the HAVEN provided production benefits reducing mortality and removals (%), and also potential savings in electricity.


2020 ◽  
Vol 22 (1) ◽  
pp. 27
Author(s):  
B.K. Kassenov ◽  
Sh.B. Kassenova ◽  
Zh.I. Sagintaeva ◽  
E.E. Kuanyshbekov ◽  
M.O. Turtubaeva

The isobaric heat capacities of novel nano-sized cobalt-cuprate-manganite of lanthanum and barium LaBaCoCuMnO6 and nickel-cuprate-manganite of lanthanum and barium LaBaNiCuMnO6 were investigated by dynamic calorimetry over the temperature range of 298.15‒673 K. It is found that a λ-shaped effect is observed on the curve of the heat capacity dependence on temperature of LaBaCoCuMnO6 at 523 K, while LaBaNiCuMnO6 also has a similar effect at 473 K. Equations for the temperature dependence of the heat capacity of cobalt(nickelite)-cuprate-manganite of lanthanum and barium are derived with allowance for the temperatures of phase transitions. Based on the experimental data, the fundamental constants ‒ the standard heat capacities of the compounds under study were found. Irrespective of the experimental data, we also calculated the standard heat capacities of the mentioned compounds using the Debye theory using the characteristic temperatures of the elements, their melting points, the Koref and Nernst-Lindemann equations. The obtained calculated data on C0p (298.15) of the compounds were in satisfactory agreement with the experimental data on the standard heat capacity. The standard entropies of LaBaCoCuMnO6 and LaBaNiCuMnO6 were calculated by the ion increment method. We calculated the temperature dependences of the enthalpy Ho(T)- Ho(298.15), entropy ΔSo(T), and the reduced thermodynamic potential ΔФ**(Т).


Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3979 ◽  
Author(s):  
Li-Shi-Bao Ling ◽  
Zheng Yin ◽  
Zhi Hu ◽  
Jun Wang ◽  
Bao-De Sun

The effects of the γ″-Ni3Nb phase on fatigue behavior of nickel-based 718 superalloys with standard heat treatment, hot isostatic pressing + solution treatment + aging, and hot isostatic pressing + direct aging were investigated by scanning electron microscope, transmission electron microscopy, and fatigue experiments. The standard heat treatment, hot isostatic pressing + solution treatment + aging, and hot isostatic pressing + direct aging resulted in the formation of more and smaller γ″ phases in the matrix in the nickel-based 718 superalloys. However, the grain boundaries of the hot isostatic pressing + direct aging sample showed many relatively coarse disk-like γ″ phases with major axes of ~80 nm and minor axes of ~40 nm. The hot isostatic pressing + direct aging sample with a stress amplitude of 380 MPa showed the longest high cycle fatigue life of 5.16 × 105 cycles. Laves phases and carbide inclusions were observed in the crack initiation zone, and the cracks propagated along the acicular δ phases in the nickel-based 718 superalloys. The precipitation of fine γ″ phases in the matrix and relatively coarse γ″ phases in the grain boundaries of the hot isostatic pressing + direct aging sample can hinder the movement of dislocation.


2019 ◽  
Vol 23 (3 Part A) ◽  
pp. 1629-1636
Author(s):  
Xiu-Rong Guo ◽  
Yu-Feng Zhang ◽  
Mei Guo ◽  
Zheng-Tao Liu

Under a frame of 2 ? 2 matrix Lie algebras, Tu and Meng [9] once established a united integrable model of the Ablowitz-Kaup-Newel-Segur (AKNS) hierarchy, the D-AKNS hierarchy, the Levi hierarchy and the TD hierarchy. Based on this idea, we introduce two block-matrix Lie algebras to present an isospectral problem, whose compatibility condition gives rise to a type of integrable hierarchy which can be reduced to the Levi hierarchy and the AKNS hierarchy, and so on. A united integrable model obtained by us in the paper is different from that given by Tu and Meng. Specially, the main result in the paper can be reduced to two new various integrable couplings of the Levi hierarchy, from which we again obtain the standard heat equation and a special Newell-Whitehead equation.


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