Optimal Heater Control in Thermoforming Preheating Using Approximate Function

2011 ◽  
Vol 314-316 ◽  
pp. 576-580
Author(s):  
Zhen Zhe Li ◽  
Gui Ying Shen ◽  
Mei Qin Li ◽  
Xiao Qian Wang ◽  
Yun De Shen

Thermoforming is one of the most versatile and economical processes available for shaping polymer products. To improve the quality of final products, the temperature difference between surface and center of sheet should be continuously minimized. But, the temperature difference between surface and center of sheet can not be freely reduced because of low thermal conductivity of sheet materials. In this paper, an analysis model was developed under the condition that the inputted heat flux was expressed by an exponential function form. In the following step, an optimal design was carried out using a 3rd order polynomial. The optimal results show that the developed method can be used to reduce the temperature difference between surface and center of sheet by adjusting the parameter of time-dependent heat flux.

2007 ◽  
Vol 31 (3) ◽  
pp. 292-299 ◽  
Author(s):  
G. K. Klute ◽  
G. I. Rowe ◽  
A. V. Mamishev ◽  
W. R. Ledoux

Elevated stump skin temperatures and the accompanying thermal discomfort are side effects of prosthesis use that may reduce amputee quality of life, particularly in hot or humid surroundings. Lower skin temperatures might be achieved through more effective heat transfer in the prosthesis, a process governed in part by the thermal conductivity of the sock, liner, and socket layers. To assess the thermodynamic properties of currently available components, an instrument capable of measuring the heat flux across a regulated temperature differential was developed. Experimental results show that the thermal conductivity ranged from 0.085 – 0.266 W/m · °K for liner materials and from 0.148 – 0.150 W/m · °K for socket materials. The results of this study demonstrate that the prescription of typical multi-layer prostheses constructed with the higher thermal conductivity materials might reduce temperature-related discomfort in patients.


2011 ◽  
Vol 314-316 ◽  
pp. 571-575
Author(s):  
Zhen Zhe Li ◽  
Gui Ying Shen ◽  
Xiao Qian Wang ◽  
Mei Qin Li ◽  
Yun De Shen

Obtaining a uniform thickness of the final product using thermoforming is difficult, and the thickness distribution depends strongly on the distribution of the sheet temperature. In this paper, the time-dependent temperature distribution of the total sheets in the storing process was studied because the temperature after the storing process is the initial temperature of the preheating process. An analysis code for simulating the storing process was developed under the condition that the thermal conductivity caused by contact resistance between sheets was assumed as a large value. In this study, the number of sheets in the storing room was adjusted for finding out the effect of it. The analysis results show that maximum temperature difference between sheets was significantly different when adjusting the number of sheets in the storing room. The temperature distribution of the total sheets and the method for analysis in this study will be used to optimize the storing process for higher quality of final products.


2010 ◽  
Vol 26-28 ◽  
pp. 1137-1141
Author(s):  
Zhen Zhe Li ◽  
Rui Jiang ◽  
Dong Ji Xuan ◽  
Tai Hong Cheng ◽  
Seoung Yun Seol ◽  
...  

Obtaining a uniform thickness of the final product using thermoforming is difficult, and the thickness distribution depends strongly on the distribution of the sheet temperature. In this paper, the time-dependent temperature distribution of the total sheets in the stage of storing was studied using the analysis code which has been verified based on the experimental data. It was found out that the time for storing should be managed for decreasing the temperature difference between the sheets. The time-dependent temperature distribution of the total sheets and the method for analysis in this study will be used to improve the quality of the final products.


2020 ◽  
pp. 35-42
Author(s):  
Yuri P. Zarichnyak ◽  
Vyacheslav P. Khodunkov

The analysis of a new class of measuring instrument for heat quantities based on the use of multi-valued measures of heat conductivity of solids. For example, measuring thermal conductivity of solids shown the fallacy of the proposed approach and the illegality of the use of the principle of ambiguity to intensive thermal quantities. As a proof of the error of the approach, the relations for the thermal conductivities of the component elements of a heat pump that implements a multi-valued measure of thermal conductivity are given, and the limiting cases are considered. In two ways, it is established that the thermal conductivity of the specified measure does not depend on the value of the supplied heat flow. It is shown that the declared accuracy of the thermal conductivity measurement method does not correspond to the actual achievable accuracy values and the standard for the unit of surface heat flux density GET 172-2016. The estimation of the currently achievable accuracy of measuring the thermal conductivity of solids is given. The directions of further research and possible solutions to the problem are given.


2019 ◽  
Vol 2 (2) ◽  
pp. 265-278
Author(s):  
Diah Rina Miftakhi ◽  
Nurjanah Nurjanah

describe the implementation of an integrated quality management component consisting of the quality of services provided by the school, human resources in teaching, the school environment, and learning process  in SLB YPAC Pangkalpinang.               The method used in this study, namely by using a naturalistic qualitative approach. Data collection is done through observation, interviews, and documentation. The subjects of this study include the principal, teachers, employees, and students. The validity of the data is done by triangulation, and deeper observation. Analysis of the data used is the interactive analysis model of Miles and Huberman through data collection, data reduction, data presentation, and conclusion drawing.              The results showed that: (a) the quality of services to students in SLB YPAC Pangkalpinang had met good service standards. This can be seen from the services in the form of facilities and infrastructure which are quite complete in schools; (b) the quality of human resources in the education process shows good teacher resources. This can be seen from the teacher data which shows that the teaching staff at SLB YPAC Pangkalpinang 95% of educators with S1 qualifications in the field of education; (c) the quality of the environment in SLB YPAC Pangkalpinang is already good. This can be seen from the very strategic location of the school because the location of the school is in the middle of the city so that it is easily accessible by the community; (d) the quality of the learning process carried out by teachers at Pangkal Pinang YPAC SLB is good. This can be seen from the realization of the form of activities through learning planning by preparing lesson plans for each subject, then implementing learning, which includes strategies and methods used by teachers in delivering learning material, and evaluation of learning. Keywords: Integrated quality management, student achievement     ABSTRAK Tujuan dalam melaksanakan penelitian ini  adalah untuk melihat pelaksanaan serta mendeskripsikan implementasi  komponen Manajemen Mutu Terpadu yang terdiri dari kualitas layanan yang diberikan sekolah, sumber daya manusia dalam mengajar, lingkungan sekolah, dan proses pembelajaran di SLB YPAC Pangkalpinang. Metode yang digunakan dalam penelitian ini, yaitu dengan menggunakan pendekatan kualitatif naturalistik. Pengumpulan data dilakukan melalui observasi, wawancara, dan dokumentasi. Subyek penelitian ini antara lain kepala sekolah, guru, pegawai, dan peserta didik. keabsahan data dilakukan dengan triangulasi, dan pengamatan yang lebih mendalam. Analisis data yang digunakan adalah model analisis interaktif Miles dan Huberman melalui kegiatan pengumpulan data, reduksi data, penyajian data, dan penarikan kesimpulan. Hasil penelitian menunjukkan bahwa: (a) mutu layanan terhadap peserta didik di SLB YPAC Pangkalpinang sudah memenuhi standar layanan yang baik. Hal ini dilihat dari layanan yang berupa fasilitas sarana dan prasarana yang sudah cukup lengkap di sekolah; (b) mutu sumber daya manusia dalam proses pendidikan menunjukkan sumber daya guru yang baik. Hal ini dapat dilihat dari data guru yang menunjukkan bahwa tenaga pengajar di SLB YPAC Pangkalpinang 95% pendidik berkualifikasi S1 bidang kependidikan; (c) mutu lingkungan yang ada di SLB YPAC Pangkalpinang sudah baik. Hal ini terlihat dari letak sekolah yang sangat strategis karena lokasi sekolah yang berada di tengah kota sehingga mudah dijangkau oleh masyarakat; (d) mutu proses pembelajaran yang dilakukan oleh guru di SLB YPAC Pangkalpinang sudah baik. Hal ini dapat dilihat dari realisasi bentuk kegiatan melalui perencanaan pembelajaran dengan menyusun RPP setiap mata pelajaran, kemudian pelaksanaan pembelajaran, yang meliputi strategi dan metode yang digunakan guru dalam menyampaikan materi pembelajaran, dan evaluasi pembelajaran.


Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4613
Author(s):  
Yi-Cheng Mao ◽  
Tsung-Yi Chen ◽  
He-Sheng Chou ◽  
Szu-Yin Lin ◽  
Sheng-Yu Liu ◽  
...  

Caries is a dental disease caused by bacterial infection. If the cause of the caries is detected early, the treatment will be relatively easy, which in turn prevents caries from spreading. The current common procedure of dentists is to first perform radiographic examination on the patient and mark the lesions manually. However, the work of judging lesions and markings requires professional experience and is very time-consuming and repetitive. Taking advantage of the rapid development of artificial intelligence imaging research and technical methods will help dentists make accurate markings and improve medical treatments. It can also shorten the judgment time of professionals. In addition to the use of Gaussian high-pass filter and Otsu’s threshold image enhancement technology, this research solves the problem that the original cutting technology cannot extract certain single teeth, and it proposes a caries and lesions area analysis model based on convolutional neural networks (CNN), which can identify caries and restorations from the bitewing images. Moreover, it provides dentists with more accurate objective judgment data to achieve the purpose of automatic diagnosis and treatment planning as a technology for assisting precision medicine. A standardized database established following a defined set of steps is also proposed in this study. There are three main steps to generate the image of a single tooth from a bitewing image, which can increase the accuracy of the analysis model. The steps include (1) preprocessing of the dental image to obtain a high-quality binarization, (2) a dental image cropping procedure to obtain individually separated tooth samples, and (3) a dental image masking step which masks the fine broken teeth from the sample and enhances the quality of the training. Among the current four common neural networks, namely, AlexNet, GoogleNet, Vgg19, and ResNet50, experimental results show that the proposed AlexNet model in this study for restoration and caries judgments has an accuracy as high as 95.56% and 90.30%, respectively. These are promising results that lead to the possibility of developing an automatic judgment method of bitewing film.


1980 ◽  
Vol 23 (8) ◽  
pp. 1532 ◽  
Author(s):  
H. Schamel ◽  
Ch. Sack
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document