Interactive tree modeling and deformation with collision detection and avoidance

We present an interactive tree modeling and deformation system that supports an efficient collision detection and avoidance using a bounding volume hierarchy of sweep surfaces. Starting with conventional tree models (given as meshes), we convert them into sweep surfaces and deform their branches interactively while detecting and avoiding collisions with many other branches. Multiple tree models (sharing the same topology) can be generated with great ease using this sweep‐based approach, and they can serve as a basis for the generation of a multiparameter family of trees. We demonstrate the effectiveness of our approach in an automatic generation of similar trees, the colonization of trees to form a forest, and the tree growth, aging, and withering simulations. Copyright © 2015 John Wiley & Sons, Ltd.     

Effect of Milling Time on the Microstructure and Thermoelectric Properties of P‐type TAGS‐90 Alloys by HEM and SPS

In this study, p‐type TAGS‐90 powders were fabricated using high‐energy milling (HEM), subsequently sintered by spark plasma sintering (SPS). And then, the effects of milling time on the microstructure, mechanical, and thermoelectric properties were investigated. The powders were quickly decreased to fine particles of ~1 μm in size and uniformly agglomerated with the increasing of milling time. XRD results indicated that all milled powders and SPSed samples showed single GeTe phase. Also, EDX results showed almost no contamination and exact composition after milling. The maximum figure of merit, ZT = 1.08, was obtained for 30‐min‐milled sample at 723 K.     

Effect of Sintering Temperature on Thermoelectric Properties of p‐Bi2Te3 Alloys Produced by Gas Atomization

In this research, p‐type Bi₂Te₃–75% Sb₂Te₃ thermoelectric alloy powders were produced by gas atomization and subsequently sintered by hot pressing at different temperatures. The grain growth of the hot‐pressed samples was observed with increasing sintering temperature from 380°C to 460°C. The compressive strength increased with increasing hot‐pressing temperature due to the high relative density of bulk samples obtained at high temperatures. The effect of sintering temperature on thermoelectric (TE) properties was studied. The maximum power factor 3.48 mW/mK² was obtained for the sample hot pressed at 420°C due to the resulting high electrical conductivity and enhanced Seebeck coefficient values.     

Mechanical Properties of Submicrometer‐Grained Transparent Yttria Ceramics by Hot Pressing with Hot‐Isostatic Pressing

Here, we report the fabrication and mechanical properties of submicrometer‐grained (0.29–0.58 μm) transparent yttria ceramics by hot pressing combined with hot‐isostatic pressing. The effects of the grain size on the microhardness and the fracture toughness were studied. An unusual decrease of the fracture toughness with an increase in the grain size was revealed, which may be attributed to the different grain size dependence of the fracture behavior of the ZrO₂‐doped yttria ceramics compared to that of other yttria ceramics. The microhardness and fracture toughness of the transparent yttria ceramics were found to be better than those of the large‐grained yttria ceramics.     

Application of Gurson Model for Evaluation of Density‐Dependent Mechanical Behavior of Polyurethane Foam: Comparative Study on Explicit and Implicit Method

Recently, liquefied natural gas (LNG) is a focus of interest around the world for several reasons, and LNG cargo containment systems (CCS) increase in quality to prevent loss of LNG during shipping. For insulation of CCS, polyurethane foam (PUF), an outstanding insulation material, is commonly used. However, until now, although its mechanical properties are relatively good, the material is not considered as a structural member under compressive loading, principal load direction in CCS. Moreover, as PUF is a porous material by mixing and foaming, its mechanical properties depend on voids, which is a dominant parameter for density. Therefore, in the present study, nonlinear behavior of PUF is described using Gurson model with a novel technique, i.e., an acceleration factor. The model expresses the behavior through the volume fraction of voids with consideration of the density effect to evaluate structural performance using user‐defined material subroutine with explicit and implicit methods.

     

Low temperature synthesis of <Emphasis Type="Italic">Manganese tungstate</Emphasis> nanoflowers with antibacterial potential: Future material for water purification

Pure water is the fundamental requisite for human life. The water has been recycled naturally but not in an adequate amount for consumption. Nanotechnology with extraordinary applications provides competent ways for the decontamination of contaminated water. In the present study MnWO₄ nanoflowers endorsed with inherent antibacterial activity were successfully synthesized by facile hydrothermal approach. XRD, SEM, EDX spectroscopy and UVDRS were used to characterize the as-synthesized nanoflowers. Gram negative Escherichia coli ATCC 52922 bacterium was used as model organism to test antibacterial activity of as-synthesized MnWO₄ nanoflowers. This study was conducted to optimize minimum concentration of MnWO₄ nanoflowers and maximum contact time required to achieve complete inactivation of bacteria present in contaminated water. Minimum inhibitory concentration (MIC) of MnWO₄ nanoflowers was found to be 10 μg/ml. The assessment and interpretation of bacterial viability was done using dual fluorescent staining. The synthesized 3D-nanoflowers were found as potent bactericides. Thus, MnWO₄ nanoflowers emerged to be very good future material for disinfection of biological pollutants present in the contaminated water reservoirs and as an anti-biofouling agent.     

Coil design optimization for an induction evaporation process: Simulation and experiment

For the purpose of utilizing induction heating in the evaporation process, the effects of induction coil design and droplet size on induction heating efficiency are investigated. Electro-magnetic simulations with various induction coil designs were conducted to predict the electro-magnetic field distribution. The induction coils were fabricated in order to verify the simulation results under atmospheric evaporation test conditions. The electro-magnetic simulation results indicated that the magnetic field became widened around the Zn droplet when the size of the Zn droplet increased. This in turn attributed to the increase in induction heating energy efficiency. The energy efficiency of the induction coil with 4-windings was the highest among the 3-, 4-, and 5-windings induction coils. Energy efficiency tendencies derived by the atmospheric evaporation tests corresponded well to the simulation results, and maximum energy efficiency was measured to be 42% under the atmospheric evaporation tests.     

State of the Art: The Immunomodulatory Role of MSCs for Osteoarthritis

Osteoarthritis (OA) has generally been introduced as a degenerative disease; however, it has recently been understood as a low-grade chronic inflammatory process that could promote symptoms and accelerate the progression of OA. Current treatment strategies, including corticosteroid injections, have no impact on the OA disease progression. Mesenchymal stem cells (MSCs) based therapy seem to be in the spotlight as a disease-modifying treatment because this strategy provides enlarged anti-inflammatory and chondroprotective effects. Currently, bone marrow, adipose derived, synovium-derived, and Wharton’s jelly-derived MSCs are the most widely used types of MSCs in the cartilage engineering. MSCs exert immunomodulatory, immunosuppressive, antiapoptotic, and chondrogenic effects mainly by paracrine effect. Because MSCs disappear from the tissue quickly after administration, recently, MSCs-derived exosomes received the focus for the next-generation treatment strategy for OA. MSCs-derived exosomes contain a variety of miRNAs. Exosomal miRNAs have a critical role in cartilage regeneration by immunomodulatory function such as promoting chondrocyte proliferation, matrix secretion, and subsiding inflammation. In the future, a personalized exosome can be packaged with ideal miRNA and proteins for chondrogenesis by enriching techniques. In addition, the target specific exosomes could be a gamechanger for OA. However, we should consider the off-target side effects due to multiple gene targets of miRNA.     

Gui-A-Gra Attenuates Testicular Dysfunction in Varicocele-Induced Rats via Oxidative Stress,ER Stress and Mitochondrial Apoptosis Pathway

Gui-A-Gra, a commercial insect powder from Gryllus bimaculatus, is registered as an edible insect by the Korean food and drug administration. The aim of this study was to investigate the effect of Gui-A-Gra on testicular damage induced by experimental left varicocele in male Sprague Dawley rats. A total of 72 rats were randomly divided into the following six groups (12 rats in each group): a normal control group (CTR), a group administrated with Gui-A-Gra 1.63 gm/kg (G1.63), a group administrated with Gui-A-Gra 6.5 gm/kg (G6.5), a varicocele (VC)-induced control group (VC), a VC-induced group administrated with Gui-A-Gra 1.63 gm/kg (VC + G1.63), and a VC-induced group administrated with Gui-A-Gra 6.5 gm/kg (VC + G6.5). Rats were administrated 1.63 or 6.5 gm/kg Gui-A-Gra once daily for 42 days. Indicators of sperm parameters, histopathology, reproductive hormones, oxidative stress, endoplasmic reticulum (ER) stress, inflammation, and mitochondrial apoptosis were analyzed to evaluate effects of Gui-A-Gra on VC-induced testicular dysfunction. Gui-A-Gra administration to VC-induced rats significantly (p < 0.05) increased sperm count and sperm motility, Johnsen score, spermatogenic cell density, serum testosterone, testicular superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase, GPx4, and steroidogenic acute regulatory protein (StAR) level. Moreover, pretreatment with Gui-A-Gra significantly (p < 0.05) decreased terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) positive cells/tubules, serum luteinizing hormone (LH), serum follicle-stimulating hormone (FSH), testicular tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), malondialdehyde (MDA), reactive oxygen species (ROS)/reactive nitrogen species (RNS) level, glucose-regulated protein-78 (Grp-78), phosphorylated c-Jun-N-terminal kinase (p-JNK), phosphorylated inositol-requiring transmembrane kinase/endoribonuclease 1α (p-IRE1α), cleaved caspase-3, and BCL2 associated X protein: B-cell lymphoma 2 (Bax: Bcl2) ratio in VC rats. These results suggest that protective effects of Gui-A-Gra on VC-induced testicular injury might be due to its antioxidant, anti-inflammatory, and androgenic activities that might be mediated via crosstalk of oxidative stress, ER stress, and mitochondrial apoptosis pathway.