3,855 research outputs found
Design and fabrication of a micro Coulter counter with thin film electrodes
We report a new approach for micro Coulter counter with thin film electrodes. Traditional Coulter counter measures DC
resistance change to sense particles passing through an aperture between two flow chambers. One of the, biggest challenges to miniaturize the device is to overcome the large resistance encountered. We propose a new approach to use thin film metal electrodes in micron size range for sensing. Resolution can be improved and it's easy for system integration. A device based on this approach was built and tested
Human Blood Cell Sensing with Platinum Black Electroplated Impedance Sensor
AC impedance sensing is an important method for biological cell analysis in flow cytometry. For micro impedance cell sensors, downsizing electrodes increases the double layer impedance of the metal-electrolyte interface, thus leaves no sensing zone in frequency domain and reduces the sensitivity significantly. We proposed using platinum black electroplated electrodes to solve the problem. In this paper, using this technique we demonstrated human blood cell sensing with high signal to noise ratio
Modified Neh Heuristic On Makespan Reduction In Permutation Flow Shop Problems
Permutation flow shop problem (PFSP) is one of the commonly reviewed machine environments in scheduling problems. The order sequence for each process remains unchanged for all machines. Few algorithms have been developed to decide the sequence of n jobs and m machines that can minimize makespan in flow shops. Throughout the past 30 years, the NEH heuristics developed by Nawaz, Enscore and Ham has been commonly regarded as the best heuristic for minimizing the makespan in permutation flow shops. Due to these findings, NEH heuristics is selected as the basis of this study. Modification is done to enhance the objectives of this study, which is makespan and idle time reduction. In this study, a total of 109 flow-shop problems were solved with the number of machines and jobs being set at a range of 4 to 25. 100 problems were carried out using numerical assessments. The process times of the jobs were randomly generated within the range of 1 to 10 using Excel spreadsheets. Whereas the remaining 9 sets of tests were carried out using real world case studies. In each case study, the company involved was provided with a surface mounting technology (SMT) service. It has the capability of planning schedules by adopting the backward scheduling technique. The proposed heuristic, NEH-M will be compared to both the historical production schedule and NEH schedule in order to verify and validate the performance of the proposed idea. The performance of the NEH-M heuristics was computed using the error deviation (ED) formula. The generated results gained through Excel modeling show that the NEH-M heuristics
outperforms the historical production schedule in all conditions. On the other hand, when the NEH-M heuristics is compared to the NEH heuristics, the overall performance of makespan reduction is underperforming while the overall performance of idle time reduction is over performing when there are large numbers of machines and jobs
Parylene membrane slot filter for the capture, analysis and culture of viable circulating tumor cells
This paper presents a method of capturing viable
circulating tumor cells (CTC) from human whole
blood using constant-pressure-driven filtration through
a specially designed parylene-C membrane “slot” filter.
More than 90% viable cancer cells could be recovered
from whole blood using the slot filter, with minimal
non-cancer blood cells left on the filter. The feasibility
of the telomerase activity measurement of a single
cancer cell taken from the filter after capture was
proven. The on-filter and off-filter cultures of the
captured cancer cells were also demonstrated
Lepton flavor violating signals of the neutral top-pion in future lepton colliders
The presence of the top-pions in the low-energy spectrum is
an inevitable feature of the topcolor scenario. Taking into account the
constraints of the present experimental limit of the lepton flavor
violating() process on the free parameters of
topcolor-assisted techicolor(TC2) models, we study the contributions of the
neutral top-pion to the processes (or ), (or ), , and via the
flavor changing () couplings and discuss the
possibility of searching for the signals via these processes in future
lepton colliders.Comment: References added, some typos corrected. Version to be published in
Phys. Rev.
Associated production of the top-pions and single top at hadron colliders
In the context of topcolor assisted technicolor(TC2) models, we study the
production of the top-pions with single top quark via the
processes and ,
and discuss the possibility of detecting these new particles at Tevatron and
LHC. We find that it is very difficult to observe the signals of these
particles via these processes at Tevatron, while the neutral and charged
top-pions and can be detecting via considering
the same sign top pair event and the (or )
event at LHC, respectively.Comment: latex files,14 pages, 7 figures. Accepted for publication in Phys.
Rev.
Extraction and antioxidant activity of phenolic compounds from wheat bran treated by steam explosion
Purpose: To use response surface methodology to optimize the extraction of the phenolic compounds in wheat bran treated by steam explosion, and to determine the antioxidant activity of the extract obtained.Methods: By using response surface methodology, the effects of extraction time, methanol concentration, liquid/solid and temperature were studied and optimized. 2,2-Diphenyl-1-(2,4,6- trinitrophenyl) hydrazyl (DPPH) radical-scavenging capacity, reducing capacity and 2,2′-Azino-bis(3- ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging capacity were also employed to determine antioxidant activity of the extract.Results: Under the optimal conditions, i.e., extraction time: 120 s, ethanol content: 43 %, liquid/solid: 35:1, temperature: 70 oC, the experimental total phenolic yield was 30.464 ± 0.025, which agreed with the predicted value of 31.687. The phenolic compounds showed strong antioxidant activities. At extract concentration of 1 mg/ml, DPPH radical-scavenging activity was 50 %. Although its reducing power (2 – 10 mg/mL) was lower than that of BHA, ABTS radical scavenging of the extract (close to 90 %) was higher than that of BHA at extract concentration > 6 mg/mL.Conclusion: The yield of the phenolic compounds was high and the compounds displayed strong antioxidant capacity, which indicates that the extraction of wheat bran under steam explosion holds high potentials for the food and pharmaceutical industries.Keywords: Wheat bran, Steam explosion, Extraction, Response surface methodology, Antioxidant capacit
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