Modeling and Simulation of Heat Transfer Phenomenon Related to Mold Heating during Investment Casting

Authors: Muhammad Musaddique Ali Rafique, Umair Shah

ABSTRACT
Cast shape during investment casting process dictates properties and service life of the casting. These properties are the function of cast part parameters (both static and dynamic), part geometry and hence mold geometry, nature and type of metal being cast, properties (extrinsic and intrinsic) and processing parameters (rate of heating, rate of cooling, rate of pouring). Improper and inadequate manipulation and modification of mold properties degrade the properties and life of casting altogether. A mathematical model is developed using standard transport equations incorporating all heat transfer coefficients (HTCs) to determine the effect of external mold heating on the properties of the final casting and a simulation is performed in C++ to validate it against experimental results. Pure iron is casted in investment molds of silica sand with zircon coating. Airflow near the mold surfaces was partially restricted due to geometry of the molds and arrangement of the pieces around a tree. The variations in heat transfer coefficient contribute towards total heat transfer out of mold surface. External heating is found to be very effective for improved casting properties. The mold heat transfer profile is found to be in good agreement with experimental values validating the effectiveness of mold heating.

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Journal: Engineering
DOI: 10.4236/eng.2020.125024(PDF)
Paper Id: 100484 (metadata)

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Finite Difference Approximation for Solving Transient Heat Conduction Equation of Copper

Authors: Dalal Adnan Maturi, Nujud Makhdhur Alsulami, Eman Salem Alaidarous

ABSTRACT
In this paper, a numerical technique is proposed to obtain the solution for transient heat conduction equation of Copper. The copper element is characterized by many characteristics; the most important of which is its high ability to conduct heat and electrical conductivity, in addition to being a flexible and malleable metal that is easy to form without being broken, making it one of the basic minerals that humans have benefited from for thousands of years, it is one of the first minerals. That has been discovered and extracted, and still plays a major role in the development of societies. The obtained solutions are compared with the available exact solutions and the obtained solutions using the finite difference method. The results indicate that the finite difference method is a highly effective method for obtaining approximate solutions for the thermal conductivity equation for copper. It is also clear from the numerical results from copper in the high conductivity of heat and electricity.

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Journal: Advances in Pure Mathematics
DOI: 10.4236/apm.2020.105021(PDF)
Paper Id: 100431 (metadata)

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Non-Invasive Approaches for Oral Potential Malignant Disorders Surveillance: A Review

Authors: Jiaying Zhou, Quan Liu, Xianyue Ren, Bin Cheng, Tong Wu

ABSTRACT
Oral potential malignant disorders (OPMDs), a series of local diseases with carcinogenic potential occurred in oral mucosa, have the possibility of developing into oral cancer. Effective diagnosis and surveillance at the early stage of OPMDs may be of help for interrupting the malignant transformation. In this review, we introduced the available non-invasive approaches of detecting the suspicious lesions, including vital staining, oral cytology, optical detection, saliva biomarkers detection, and image analysis, which can enhance the detection efficiency for the early diagnosis and surveillance of OPMDs. However, limitations which restrict the clinical application of these approaches still exist. How to improve the sensitivity and specificity of these techniques deserves further detailed study.

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Journal: Advances in Bioscience and Biotechnology
DOI: 10.4236/abb.2020.115015(PDF)
Paper Id: 100394 (metadata)

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Quantification Detection of Probiotic Bacteria Based on Plasmonic Gold-Nanoparticle Sensors

Author: Fangqi Di

ABSTRACT
Probiotic products are of significant research interest in recent years due to their powerful health benefits. One of the most popular commercial probiotic products is probiotic milk drinks containing Lactobacillus bacteria. The quality and effectiveness of such drinks are highly dependent on their bacterial content. However, such information is only available in producers’ advertisements—which may be misleading, and there are few studies done on the true bacterial content of these drinks. More significantly, conventional methods of measuring Lactobacillus bacterial content are laborious and time-consuming. Hence, this research aims to develop a fast and easy test that shows visible results rapidly and can be applied to other Lactobacillus-containing products. Recent developments have presented gold nanoparticles as a strong candidate for various applications in chemistry, physics, and biology for their unique optical properties. One essential optical property of gold nanoparticles is their red or blue color due to plasmon resonance. In this research, strong potential for this property of gold nanoparticles is recognised in a novel method of measuring the bacterial CFU in probiotic milk drinks. Gold nanoparticles function as the key material and indicator in this method as they are found capable of adhering to the Lactobacillus bacteria. The bacterial CFU can then be determined from the amount of gold nanoparticles attached to the bacteria. The eventual measuring scheme established enables fast (15 – 16 times faster than colony counting) and convenient (a sterile environment is not necessary) tests of the bacterial CFU in different probiotic milk drinks and has great potential in other related applications.

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Journal: American Journal of Analytical Chemistry
DOI: 10.4236/ajac.2020.115017(PDF)
Paper Id: 100357 (metadata)

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Vision and Geolocation Data Combination for Precise Human Detection and Tracking in Search and Rescue Operations

Author: Lygouras Eleftherios

ABSTRACT
In this paper, a study and evaluation of the combination of GPS/GNSS techniques and advanced image processing algorithms for distressed human detection, positioning and tracking, from a fully autonomous Unmanned Aerial Vehicle (UAV)-based rescue support system, are presented. In particular, the issue of human detection both on terrestrial and marine environment under several illumination and background conditions, as the human silhouette in water differs significantly from a terrestrial one, is addressed. A robust approach, including an adaptive distressed human detection algorithm running every N input image frames combined with a much faster tracking algorithm, is proposed. Real time or near-real-time distressed human detection rates achieved, using a single, low cost day/night NIR camera mounted onboard a fully autonomous UAV for Search and Rescue (SAR) operations. Moreover, the generation of our own dataset, for the image processing algorithms training is also presented. Details about both hardware and software configuration as well as the assessment of the proposed approach performance are fully discussed. Last, a comparison of the proposed approach to other human detection methods used in the literature is presented.

Source:

Journal: International Journal of Intelligence Science
DOI: 10.4236/ijis.2020.103004(PDF)
Paper Id: 100328 (metadata)

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Menopausal Symptoms in Japanese Nurses: Differences between Smokers and Non-Smokers

Authors: Yukie Matsuura, Kazuyo Matsuzaki, Toshiyuki Yasui

ABSTRACT
As a low-cost marketing model, telemarketing has always been the most important channel for banks to promote wealth management products. Traditional telemarketing has not only brought intrusiveness to many telephone access customers, but also a waste of resources for the bank itself. In order to improve the success rate of bank telemarketing, it is necessary to predict in advance which customers are most likely to purchase the wealth management product, so as to achieve precision marketing. Aiming at the complex high-dimensional nonlinear characteristics of the factors affecting the success rate of telemarketing, a t-SNE (t-distributed stochastic neighbor embedding) feature extraction method, and then take the extracted low-dimensional features as input, use nonlinear support vector machine (SVM) for training and prediction. The empirical results show that the bank phone based on t-SNE-SVM proposed in this paper. The marketing prediction model has good learning ability and generalization ability, which can provide certain decision-making reference for banks and other industries to achieve precision marketing.

Source:

Journal: Health
DOI: 10.4236/health.2020.125037(PDF)
Paper Id: 100291 (metadata)

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Bank Telemarketing Forecasting Model Based on t-SNE-SVM

Authors: Jianguo Che, Sai Zhao, Yongfan Li, Kai Li

ABSTRACT
As a low-cost marketing model, telemarketing has always been the most important channel for banks to promote wealth management products. Traditional telemarketing has not only brought intrusiveness to many telephone access customers, but also a waste of resources for the bank itself. In order to improve the success rate of bank telemarketing, it is necessary to predict in advance which customers are most likely to purchase the wealth management product, so as to achieve precision marketing. Aiming at the complex high-dimensional nonlinear characteristics of the factors affecting the success rate of telemarketing, a t-SNE (t-distributed stochastic neighbor embedding) feature extraction method, and then take the extracted low-dimensional features as input, use nonlinear support vector machine (SVM) for training and prediction. The empirical results show that the bank phone based on t-SNE-SVM proposed in this paper. The marketing prediction model has good learning ability and generalization ability, which can provide certain decision-making reference for banks and other industries to achieve precision marketing.

Source:

Journal: Journal of Service Science and Management
DOI: 10.4236/jssm.2020.133029(PDF)
Paper Id: 100260 (metadata)

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Archaeometallurgical Analysis of Bronze Artifacts: A Magnetometer Approach

Author: Lucas Braddock Chen

ABSTRACT
Bronze has been utilized by human civilization for the past five millennia, and societies across the globe have mined, extracted, and purified copper and tin to create bronze alloys. Due to the different mineral composition of ores and the varying techniques involved with metal smelting, bronze artifacts from around the world often have very different chemical compositions. The determination of chemical composition is often invasive and expensive, and is usually conducted in laboratories. We previously developed an inexpensive and mobile test to identify metal alloys based on their magnetic signatures. We demonstrated that metals of different compositions would exhibit different electrical conductivity, and thus different magnetic field strengths when evoked by different levels of electric current. In this manuscript, we now detail the experiment protocol to produce evoked dynamic electromagnetic signals from bronze alloys, and the capture of signals with the smartphone magnetometer.

Source:

Journal: Archaeological Discovery
DOI: 10.4236/ad.2020.83011(PDF)
Paper Id: 100210 (metadata)

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Love Dynamical Models with Delay

Authors: Kaori Saito, Shiho Takagi, Yoshihiro Hamaya

ABSTRACT
A sufficient condition for the asymptotic stability of the equilibrium point of a system, which appears as a model for couple of the love affair with time delay, is obtained by applying the technique of linearized method and Hopf-bifurcation.

Source:

Journal: Advances in Pure Mathematics
DOI: 10.4236/apm.2020.105017(PDF)
Paper Id: 100177 (metadata)

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Change in Deferring Time Correlate to Improved Female Sexual Function after Anal Sphincter Repair: A Prospective Study

Authors: Johan Danielson, Urban Karlbom, Ann-Cathrine Sonesson, Wilhelm Graf

ABSTRACT
Background: Many women suffer from sexual problems after anal sphincter tears due to obstetric trauma. Aim: The study aimed to assess changes in sexual function after anal sphincter repair. Methods: The study was a non-randomized prospective observational cohort study. Inclusion of the study was done at the University Hospital, Uppsala, Sweden, between 2002 and 2007. Thirty-nine consecutive female patients admitted for anal sphincter repair were invited to the study. Twenty patients accepted and were included, four were lost to follow up and one was unevaluable (due to the formation of a stoma) leaving a study group of 15 patients. The patients were assessed with questionnaires before surgery and at three and 12 months after surgery. Outcomes: Change in reported sexual activity and dyspareunia. Results: Before surgery, 12/15 patients reported that their sexual life was impaired due to anal incontinence. The corresponding figure at 12 months was 9/15 (p = 0.43). Three patients remained sexually inactive throughout the study, five patients increased their sexual activity and one had decreased activity. Out of the 12 who were active, four stated dyspareunia at baseline, and only one reported dyspareunia at 12 months. The mean Miller incontinence scores at baseline and 12 months were 10.1 and 8.7, respectively. The change in incontinence score did not differ between those with decreased, stable or increased sexual activity. However, there was a definite correlation (r = 0.54 – 0.60, p < 0.05) between change in sexual function and deferring time for stool. Clinical Implications: Operative management of anal sphincter tears alone is not curative for sexual problems due to anal incontinence but can be a part of the treatment. Strengths and Limitations: The study is a prospective study of sexual function. The limitations are that the questionnaires were not validated due to lack of such questionnaires at the time of the study and that the study population is quite small. Conclusion: Patients with a sphincter injury and fecal incontinence often have an impaired sexual function. Increased deferring time for stools after surgery increases the likelihood of improved sexual function.

Source:

Journal: Open Journal of Obstetrics and Gynecology
DOI: 10.4236/ojog.2020.1050067(PDF)
Paper Id: 100169 (metadata)

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