scholarly journals Design of Automated Screen-Printing Machine

Author(s):  
Utsav Dedhia

India being one of the growing countries still uses manual screen-printing methods which involves using bare hands to spread the ink across and film and aligning the film with the print surface along with loading and unloading of material. This process is very time consuming and results in a decline in production rate. Automating these movements of the process help in enhancing quality of the print and an increase in the production rates and process time which in turn reduces labour cost.

1972 ◽  
Vol 70 (1) ◽  
pp. 89-96 ◽  
Author(s):  
M. J. Levell

ABSTRACT Five normal subjects were given [14C] cortisol in the morning and [3H] cortisol in the evening, in both cases by mouth. The excretion of radioactivity in tetrahydrocortisol (THF) and tetrahydrocortisone (THE) was measured by a modified form of reverse isotope dilution. In 2 subjects, the ratio of isotopic THF/isotopic THE was higher after the evening dose than after the morning dose. In 1 subject the ratio decreased. In 2 subjects it did not change. Cortisol production rates calculated from THF were usually higher than those calculated from THE. The observed variations of metabolism were only a contributory factor to these discrepancies.


2006 ◽  
Vol 71 (6) ◽  
pp. S496-S500 ◽  
Author(s):  
C.O. Mohan ◽  
C.N. Ravishankar ◽  
J. Bindu ◽  
V. Geethalakshmi ◽  
T.K. Srinivasa Gopal

2017 ◽  
Vol 5 (3) ◽  
pp. 479-492 ◽  
Author(s):  
Jon D. Pelletier

Abstract. The potential soil production rate, i.e., the upper limit at which bedrock can be converted into transportable material, limits how fast erosion can occur in mountain ranges in the absence of widespread landsliding in bedrock or intact regolith. Traditionally, the potential soil production rate has been considered to be solely dependent on climate and rock characteristics. Data from the San Gabriel Mountains of California, however, suggest that topographic steepness may also influence potential soil production rates. In this paper I test the hypothesis that topographically induced stress opening of preexisting fractures in the bedrock or intact regolith beneath hillslopes of the San Gabriel Mountains increases potential soil production rates in steep portions of the range. A mathematical model for this process predicts a relationship between potential soil production rates and average slope consistent with published data. Once the effects of average slope are accounted for, a small subset of the data suggests that cold temperatures may limit soil production rates at the highest elevations of the range due to the influence of temperature on vegetation growth. These results suggest that climate and rock characteristics may be the sole controls on potential soil production rates as traditionally assumed but that the porosity of bedrock or intact regolith may evolve with topographic steepness in a way that enhances the persistence of soil cover in compressive-stress environments. I develop an empirical equation that relates potential soil production rates in the San Gabriel Mountains to the average slope and a climatic index that accounts for temperature limitations on soil production rates at high elevations. Assuming a balance between soil production and erosion rates on the hillslope scale, I illustrate the interrelationships among potential soil production rates, soil thickness, erosion rates, and topographic steepness that result from the feedbacks among geomorphic, geophysical, and pedogenic processes in the San Gabriel Mountains.


Author(s):  
Rasheda Begum Dina ◽  
Md Zulhash Uddin ◽  
UmmulKhair Fatema

In semi solid design, the parameters of the quality of the printed fabric were color fastness, level of print detail, color difference, print coverage, saw-tooth effect, line sharpness etc. Actually, printed fabric quality was evaluated by these parameters. Again, print coverage, saw-tooth effect, line sharpness, etc. were examined by estimating different distances, angles etc. in printed fabric and these factors were compared with image positives. Mesh opening effect on the quality of screen printed fabric was investigated after printing the semi solid design on knit fabric using different mesh count screens and different types of the link. To print semi solid design on knit fabric different types of ink as well as non-identical mesh count was used. Then mesh screen out come on the design and form of printed fabric in screen printing was examined. For the evaluation of semi solid design effect there remains two different methods.The first one is visual assessment and another way is microscope observation. Here, to determine the probability of the amount of ink flowing by the screen, mesh opening area of every screen was considered and it was done from respective digital microscope images.


2021 ◽  
Vol 10 (2) ◽  
pp. 103-117
Author(s):  
Nurul Istifadhoh ◽  
Zahida I’tisoma Billah ◽  
Hafidhotul Mufidah

Koperasi Produsen Syariah Industri Kreatif is a cooperative sharia which has a role to improve the quality of life member through the efforts of  Small and Medium Enterprise (SME). SME  that exist in Koperasi Produsen Syariah Industri Kreatif is engaged in the field of industry creative. While maqashid sharia is an Islamic law that has the intent and purpose is important in the life of man, namely obtaining the benefit. Through the concept, among others: 1) the absorption of knowledge and increased education of members; 2) conveying a sense of justice for the community, especially members; 3) the realization of member welfare. The method that is used in the article it is a method of qualitative were then analyzed by descriptive qualitative. Analisis maqashid syariah pada Koperasi Produsen Syariah Industri Kreatif di Bojonegoro runs according to the concept and purpose, namely that the educational process obtained by members is very positive for members of the Koperasi Produsen Syariah Industri Kreatif, the availability of batik, convection and screen printing materials makes it easier for members to increase production, increase finances family as well as the ability to utilize technology for the members' creative industry businesses which are increasingly growing. As the function of the sharia cooperative itself is to encourage people's lives to prosper and benefit.


2018 ◽  
Vol 2018 (1) ◽  
pp. 000665-000671
Author(s):  
Jianbiao Pan ◽  
Malcolm Keif ◽  
Joshua Ledgerwood ◽  
Xiaoying Rong ◽  
Xuan Wang

Abstract The lightweight and bendable features of printed flexible electronics are increasingly attractive. Currently stretchable silver inks are formulated for wide traces, typically larger than 2 mm. To attach ultra-thin silicon chips that have fine pitch onto printed organic substrate, it is necessary to print fine trace width/space that matches the pitch of the chips, which may be less than 200 microns. This paper presents the development and optimization of the screen printing process for printing stretchable silver ink onto stretchable thermoplastic polyurethane (TPU) substrate. A test vehicle was designed including 50 μm/5 mm (line width/line length) to 350 μm/35 mm lines (at 4 biases). The stretchable ink selected was DuPont PE 873 and Dupont's PE 5025 ink (non-stretchable conductive flake silver) was used as a “control” to baseline the printing process. The substrate used was Bemis TPU ST604. The experiment was done on a DEK Horizon 03i printer. A DEK squeegee 200 (Blue) and a DEK 265 flood bar (200 mm) were used. A 2-level factorial design with three replicates was selected to investigate the effect of process parameters on the quality of prints. The quality of the prints is characterized by 1) resistance of traces, 2) sheet resistance, 3) z-axis height, and 4) trace width/spacing. We observed significant noise in the z-axis printed silver ink height measured by profilometry and concluded z-axis height is not a good response variable for characterizing screen printing stretchable silver ink onto TPU substrate, mainly due to high roughness of the TPU substrate. We proposed calculated sheet resistance based on the measured resistance value, trace width, and trace length, which can replace trace height measurements on rough profile substrates. We found that squeegee pressure and emulsion thickness have statistically significant effects on calculated sheet resistance of print traces while print speed does not have statistically significant effects. In our experiment setting levels, the lower the squeegee pressure, the lower the calculated sheet resistance that is achieved. The emulsion with higher emulsion over mesh (EOM) is better than the emulsion with lower EOM since it can achieve lower sheet resistance. After optimizing the screen printing process, we were able to print 100 μm (4 mils) trace width and spacing with high consistency.


2019 ◽  
Author(s):  
Yongliang Bai ◽  
Diya Zhang ◽  
Dongdong Dong ◽  
Shiguo Wu ◽  
Zhenjie Wang

Abstract. The variation in island arc magma production rates and their influencing mechanisms are of great significance since island arc magma is considered a main source of continental crust growth. The island arc magma directly originates from the molten mantle wedge, and the mantle melting is driven by fluids or melts from the subducted slab. Slab dehydration flux mainly depends on the slab thermal structures, and subducted slab melting requires a sufficiently high temperature. For the Aleutian subduction system, the subducted Pacific Plate has diverse thermal structures due to the existing fracture zones, ridges and slab window, so it is an ideal region for arc magma production rate research. However, the previous estimations are based on seismic profiles that only provide magma production rates at specific regions of the Aleutian arc, and these results are controversial. Here, we design a magma production rate estimation method based on gravity inversion constrained by deep seismic profiles. The first overview map of magma production rates along the Aleutian arc strike demonstrates that the magma production rates have the same trend as the slab dips, and the peaks correspond to the subduction of the fracture zones and ridges. The potential mechanisms for these correlations are as follows: (1) Slab water flux at subarc depths increases with increasing slab dip. More fluid flux would induce more mantle melting, and so the arc magma production rates are increased. (2) Water-rich serpentine is formed by hydrothermal alteration on or near the surface of the subducted slab when there are fracture zones. Serpentine decomposition at a depth of 80–120 km releases fluids in addition to the fluids released during normal slab dehydration. Therefore, more fluids induce more mantle melting and correspond a larger magma production rate. (3) The slab located in the Emperor Seamounts has a relatively high temperature and is also weak, so its melting is easier. Similarly, more slab melt means more mantle melt and a higher island arc magma production rate.


Author(s):  
Xiannong Meng ◽  
Song Xing

This chapter reports the results of a project attempting to assess the performance of a few major search engines from various perspectives. The search engines involved in the study include the Microsoft Search Engine (MSE) when it was in its beta test stage, AllTheWeb, and Yahoo. In a few comparisons, other search engines such as Google, Vivisimo are also included. The study collects statistics such as the average user response time, average process time for a query reported by MSE, as well as the number of pages relevant to a query reported by all search engines involved. The project also studies the quality of search results generated by MSE and other search engines using RankPower as the metric. We found MSE performs well in speed and diversity of the query results, while weaker in other statistics, compared to some other leading search engines. The contribution of this chapter is to review the performance evaluation techniques for search engines and use different measures to assess and compare the quality of different search engines, especially MSE.


1995 ◽  
Vol 31 (7) ◽  
pp. 169-179 ◽  
Author(s):  
T. Hvitved-Jacobsen ◽  
K. Raunkjær ◽  
P. H. Nielsen

The main objective was to study the anaerobic transformation of organic matter and sulfide production during wastewater transportation. Emphasis was on the transformation of easily biodegradable organic matter in terms of volatile fatty acids (VFA). Samples from two intercepting pressure mains located in the Northern part of Jutland, Denmark, were taken. The concentration of VFA in the wastewater varied considerably during day and night, being typically between 5 and 50 g/m3. A net production as well as a net removal of VFA was seen during transportation in the pressure mains probably depending on the quality and quantity of the organic matter. Typically 85% of the VFA was acetate and 10% propionate; the remainder was formate, n-butyrate and iso-butyrate. Observed sulfide production rates from the sewer biofilms were typically 0.05 and 0.005 g S/m2 h at 12 and 4 °C, respectively. A high sulfide production rate corresponded with a high VFA concentration. TOC removal was observed in the pressure mains.


Author(s):  
Dinu Thomas Thekkuden ◽  
Abdel-Hamid I. Mourad ◽  
Abdel-Hakim Bouzid

Abstract The stress corrosion cracking of tube-to-tubesheet joints is one of the major faults causing heat exchanger failure. After the expansion process, the stresses are developed in a plastically deformed tube around the tube-to-tubesheet joint. These residual stressed joints, exposed to tube and shell side fluids, are the main crack initiation sites. Adequate contact pressure at the tube-to-tubesheet interface is required to produce a quality joint. Insufficient tube-to-tubesheet contact pressure leads to insufficient joint strength. Therefore, a study on the residual stress and contact pressure that have a great significance on the quality of the tube-to-tubesheet joint is highly demanded. In this research, a 2D axisymmetric numerical analysis is performed to study the effect of the presence of grooves in the tubesheet and the expansion pressure length on the distribution of contact pressure and stress during loading and unloading of 400 MPa expansion pressure. The results show that the maximum contact pressure is independent of the expansion pressure length. However, the presence of grooves significantly increased the maximum contact pressure. It is proven that the presence of grooves in the tubesheet is distinguishable from the maximum contact pressure and residual von mises equivalent stress. The tube pull-out strength increases with the expansion pressure and the number of grooves. In conclusion, the presence of the grooves affects the tube-to-tubesheet joints.


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