The Influences of Oxygen Concentration and External Heating on Carbon Nanotube Growth in Diffusion Flame

Tight control of the carbon nanotube (CNT) synthesis process in flames remains a challenge due to the highly non-uniform gradient of flame thermochemical properties. The present study aims to establish a baseline model for flame-enhanced chemical vapor deposition (FECVD) synthesis of CNT and to analyze the CNT growth region at varying flame and furnace conditions. The numerical model comprises a computational fluid dynamics (CFD) simulation that is coupled with the CNT growth rate model to simulate the flow field within the furnace and the CNT growth respectively. Validation of the flame shape, flame length, and temperature profile are carried with a reasonable comparison to experimental measurements. A parametric study on the effects of furnace heating capacity and oxidizer concentration is conducted. The results of the CNT growth rate model reveal that there is a positive correlation between the heater power and CNT length. Supplying a higher concentration oxidizer at a fixed furnace power is predicted to result in further improvement in CNT length and high yield region. Flame structure analysis showed that with the heater turned on at 750 W (corresponding to heat flux of 21,713W/m2), the growth region expands twofold when oxygen concentration is increased from 19% to 24%. However, the growth region shrinks when the oxygen concentration is further increased to 27% which indicates depletion of carbon source for CNT growth due to excess oxygen. The finding of this research could guide and optimize the experiment of the flame-assisted CNT production in the future.

Comparative Proteomics of Human Milk From Eight Cities in China During Six Months of Lactation in the Chinese Human Milk Project Study

Human milk (HM) is the golden standard of infant nutrition that can protect immature body function and enhance nutrition metabolism to ensure infant growth. Region specificity and lactation period could change the protein composition in HM. In this research, proteomics analysis was used to compare proteomes across eight cities, namely Harbin, Lanzhou, Guangzhou, Chengdu, Jinhua, Weihai, Zhengzhou, and Beijing, which represented the northeast, northwest, southeast, southwest, east, and north and central regions of China,. Proteins varied significantly among the cities. These different proteins were mainly involved in the process of platelet degranulation, innate immune response, and triglyceride metabolic process, which might be due to different living environments. These differences also lead to variation in protection and fat metabolism from mothers to infants in different cities. Four proteins were expressed differently during 6 months of lactation, namely Dipeptidyl peptidase 1, Lysozyme C, Carbonic anhydrase 6, and Chordin-like protein 2. The changes in these proteins might be because of the change of growth needs of the infants. The findings from our results might help to improve the understanding of HM as well as to design infant formula.

Numerical Analysis of Solidification Behavior during Laser Welding Nickel-based Single-crystal Superalloy Part III: Auspicious Control of Dendrite Tip Undercooling

Location-dependent dendrite tip undercooling is numerically elucidated to predict crystallography-assisted resistance to centerline grain boundary formation and morphology transition of stray grain formation ahead of dendrite tip in the ternary Nickel-Chromium-Aluminum molten pool during course of nonequilibrium solidification for explanation arduous solidification behavior control of microstructure melioration. Heat input is not so salient as welding configuration for auspicious solidification behavior and beneficial microstructure development. Advantageous symmetry of welding configuration efficiently lessens dendrite tip undercooling for prevalent dendrite morphology stability of planar interface with alleviation of columnar/equiaxed transition (CET) phenomenon. The bimodal distribution of undercooling ahead of dendrite tip is symmetrically dominant for (001)/[100] growth crystallography with capability of increasing morphology of interface kinetics for epitaxial growth and guarantees single-crystal potential. Alternatively, the distribution of undercooling ahead of dendrite tip is asymmetrically prevalent for (001)/[110] growth crystallography with inefficiency of nonhomologous solidification behavior for discontinuous intersection of solidification interface. Undercooling ahead of dendrite tip inside [010] growth region is not so wide as inside [100] growth region, where thermometallurgically initiates unstable solidification interface and inferior solidification behavior, with unfavorable crystallography in the case of asymmetrical (001)/[110] welding configuration. The smaller heat input is applied, the narrower undercooling ahead of dendrite tip is acquired to significantly mitigate microstructure anomalies with favorable solidification conditions, meliorate metallurgical properties and potentially improve weldability with viability of epitaxial columnar morphology and vice versa. Optimum heat input, especially low laser power and high welding speed together, is a viable and robust way to limit plethora of undercooling and easily decrease solidification behavior anomalies. When low laser power or rapid welding speed is chosen, low heat input not only lessens [100] dendrite growth region, where is spontaneously vulnerable to columnar/equiaxed transition, as ramification of prominent dendrite tip undercooling, but also metallurgically ameliorates [001] dendrite growth region, where morphologically aids epitaxial growth and activates stable planar interface, with achievable diminution of dendrite tip undercooling. Symmetrical (001)/[100] welding configuration, in which undercooling ahead of dendrite tip is preferably narrower than asymmetrical (001)/[110] welding configuration, is one of the most important ingredient for auspicious control of dendrite tip undercooling, once other welding conditions are similar. The main reason, why welding conditions (both low heat input and (001)/[100] welding configuration) is quite superior to welding conditions (both high heat input and (001)/[110] welding configuration), is attributable to favorable crystallography-dependent thermometallurgical factors to suppress inhomogeneous microstructure as long as solidification conditions within marginal stability range. Satisfying crack-free microstructure development is strongly interdependent on kinetics-related solidification behavior through scrupulous control of dendrite tip undercooling to balance between microstructure amelioration and weld depth requirement. The mechanism of columnar/equiaxed transition elimination, by which kinetic driving forces of abnormal microstructure development within high-undercooling region on either left or right side of weld pool is diminished through challenging method of crystallography-dependent dendrite tip undercooling control, is therefore proposed. Finally, there is reasonable consensus between numerical analysis results and experiment results. The numerical analysis provides credible insight into where is liable to microstructure anomalies and why dendrite tip undercooling suppresses stray grain formation for successful laser surface modification of Ni-based single-crystal superalloy.

An Extended Approach to Predict Retinopathy in Diabetic Patients Using the Genetic Algorithm and Fuzzy C-Means

The present study is developed a new approach using a computer diagnostic method to diagnosing diabetic diseases with the use of fluorescein images. In doing so, this study presented the growth region algorithm for the aim of diagnosing diabetes, considering the angiography images of the patients’ eyes. In addition, this study integrated two methods, including fuzzy C-means (FCM) and genetic algorithm (GA) to predict the retinopathy in diabetic patients from angiography images. The developed algorithm was applied to a total of 224 images of patients’ retinopathy eyes. As clearly confirmed by the obtained results, the GA-FCM method outperformed the hand method regarding the selection of initial points. The proposed method showed 0.78 sensitivity. The comparison of the fuzzy fitness function in GA with other techniques revealed that the approach introduced in this study is more applicable to the Jaccard index since it could offer the lowest Jaccard distance and, at the same time, the highest Jaccard values. The results of the analysis demonstrated that the proposed method was efficient and effective to predict the retinopathy in diabetic patients from angiography images.

Presentation of Novel Hybrid Algorithm for Detection and Classification of Breast Cancer Using Growth Region Method and Probabilistic Neural Network

Mammography is a significant screening test for early detection of breast cancer, which increases the patient’s chances of complete recovery. In this paper, a clustering method is presented for the detection of breast cancer tumor locations and areas. To implement the clustering method, we used the growth region approach. This method detects similar pixels nearby. To find the best initial point for detection, it is essential to remove human interaction in clustering. Therefore, in this paper, the FCM-GA algorithm is used to find the best point for starting growth. Their results are compared with the manual selection method and Gaussian Mixture Model method for verification. The classification is performed to diagnose breast cancer type in two primary datasets of MIAS and BI-RADS using features of GLCM and probabilistic neural network (PNN). Results of clustering show that the presented FCM-GA method outperforms other methods. Moreover, the accuracy of the clustering method for FCM-GA is 94%, as the best approach used in this paper. Furthermore, the result shows that the PNN methods have high accuracy and sensitivity with the MIAS dataset.

Numerical Analysis of Stray Grain Formation during Laser Welding Nickel-Based Single-Crystal Superalloy Part II: Multicomponent Dendrite Growth

Multicomponent dendrite growth is theoretically predicted to optimize solidification cracking susceptibility during ternary Ni-Cr-Al nickel-based single-crystal superalloy weld pool solidification. The distribution of dendrite trunk spacing along the weld pool solidification interface is clearly symmetrical about the weld pool centerline in beneficial (001)/[100] welding configuration. The distribution of dendrite trunk spacing along the weld pool solidification interface is crystallography-dependent asymmetrical from bottom to top surface of the weld pool in detrimental (001)/[110] welding configuration. The smaller heat input is used, the finer dendrite trunk spacing is kinetically promoted by less solute enrichment and narrower constitutional undercooling ahead of solid/liquid interface with mitigation of metallurgical contributing factors for solidification cracking and vice versa. Vulnerable [100] dendrite growth region is predominantly suppressed and epitaxial [001] dendrite growth region is favored to spontaneously facilitate single-crystal columnar dendrite growth and reduce microstructure anomalies with further reduction of heat input. Optimum low heat input (both lower laser power and higher welding speed) with (001)/[100] welding configuration is the most favorable one to avoid nucleation and growth of stray grain formation, minimize both dendrite trunk spacing and solidification cracking susceptibility potential, improve resistance to solidification cracking, and ameliorate weldability and weld integrity through microstructure modification instead of inappropriate high heat input (both higher laser power and slower welding speed) with (001)/[110] welding configuration. The dendrite trunk spacing in the [100] dendrite growth region on the right side of the weld pool is considerably coarser and grows faster than that within the [010] dendrite growth region of the left side in the (001)/[110] welding configuration to deteriorate weldability, although the welding conditions are the same on the either side. Furthermore, the alternative mechanism of crystallography-dependent solidification cracking as consequence of asymmetrical microstructure development and diffusion-controlled dendrite growth of γ phase is therefore proposed. The theoretical predictions are comparable with experiment results. The reliable model is also useful for welding conditions optimization for crack-free laser processing.

Numerical Analysis of Stray Grain Formation during Laser Welding Nickel-Based Single-Crystal Superalloy Part III: Crystallography-Dependent Solidification Behavior

The solidification temperature range was numerically analyzed to optimize nonequilibrium solidification behavior during ternary Ni-Cr-Al nickel-based single-crystal superalloy weld pool solidification with variation of laser welding conditions (either heat input or welding configuration). The distribution of solidification temperature range along the fusion boundary is beneficially symmetrical about the weld pool centerline in the (001)/[100] welding configuration. The distribution of solidification temperature range along the fusion boundary is detrimentally asymmetrical about the weld pool centerline in the (001)/[110] welding configuration. The stray grain formation and solidification cracking are preferentially confined to [100] dendrite growth region. [001] epitaxial growth region with columnar dendrite morphology is favored at the expense of undesirable [100] growth region with equiaxed dendrite morphology to facilitate essential single-crystal solidification with considerable reduction of heat input. The smaller heat input is used, the narrower solidification temperature range is thermodynamically promoted to reduce nucleation and growth of stray grain formation with decrease of constitutional undercooling ahead of dendrite tip and mitigate thermo-metallurgical factors for morphology instability and microstructure anomalies. Potential low heat input(both decreasing laser power and increasing welding speed) with (001)/[100] welding configuration decreases solidification temperature range to significantly minimize columnar/equiaxed transition (CET) and stray grain formation, and improve resistance to solidification cracking through microstructure control. On both sides of weld pool are imposed by the same heat input, while the solidification temperature range along the fusion boundary inside of [100] dendrite growth region on the right part of the weld pool is spontaneously wider than that of [010] dendrite growth region on the left part to increase solidification cracking susceptibility in the (001)/[110] welding configuration. Furthermore, another mechanism of solidification cracking as consequence of severe solidification behavior and anomalous microstructure with asymmetrical crystallographic orientation is therefore proposed. The theoretical predictions are well verified by experiment results. The useful and satisfactory numerical modeling is also available for other single-crystal superalloys during successful laser repair process without stray grain formation.

Environmental and Radar Characteristics of Gargantuan Hail-Producing Storms

Storms that produce gargantuan hail (defined here as ≥ 6 inches or 15 cm in maximum dimension), although seemingly rare, can cause extensive damage to property and infrastructure, and cause injury or even death to humans and animals. Currently, we are limited in our ability to accurately predict gargantuan hail and detect gargantuan hail on radar. In this study, we analyze the environments and radar characteristics of gargantuan hail-producing storms to define the parameter space of environments in which gargantuan hail occurs, and compare environmental parameters and radar signatures in these storms to storms producing other sizes of hail. We find that traditionally used environmental parameters used for severe storms prediction, such as most unstable convective available potential energy (MUCAPE) and 0–6 km vertical wind shear, display considerable overlap between gargantuan hail-producing storm environments and those that produce smaller hail. There is a slight tendency for larger MUCAPE values for gargantuan hail cases, however. Additionally, gargantuan hail-producing storms seem to have larger low-level storm-relative winds and larger updraft widths than those storms producing smaller hail, implying updrafts less diluted by entrainment and perhaps maximizing the liquid water content available for hail growth. Moreover, radar reflectivity or products derived from it are not different from cases of smaller hail sizes. However, inferred mesocyclonic rotational velocities within the hail growth region of storms that produce gargantuan hail are significantly stronger than the rotational velocities found for smaller hail categories.

DEPRESSED REGIONS OF GEORGIA HAVE GOOD OPPORTUNITIES FOR INCLUSIVE DEVELOPMENT THROUGH TOURISM

The article - "Depressed regions of Georgia have good opportunities for inclusive development through tourism" - consists of the following parts:  Introduction.  Definitions of terms.  The need for inclusive growth in the world and in Georgia.  Priorities of inclusive growth in the depressed regions of Georgia.  Potential for tourism development in the depressed regions of Georgia.  Summarizing conclusion. The article brings to the forward the issue of priority development of the economically backward (depressed) regions and different parts of Georgia - Racha-Lechkhumi, Samtskhe-Javakheti, Pshav-Khevsureti, Tusheti and others, through the development of tourism. This opinion of the author is based on the resources needed for the development of tourism in these regions, about what the other Georgian scientists - I. Khelashvili, K. Arabuli, d. Gabunia and others - write a lot. Keywords: Tourism; Inclusive; Inclusive tourism; Inclusive growth; Region; Poverty and inequality.