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Number of results: 7
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Abstract

As the dynamic behavior of the concrete is different from that under static load, this research focuses on the study of dynamic responses of concrete by simulating the split Hopkinson pressure bar (SHPB) test. Finite element code LS-DYNA is used for modeling the dynamic behaviors of concrete. Three continuous models are reviewed and the Holmquist-Johnson-Cook model (HJC) is introduced in detail. The HJC model which has been implemented in LS-DYNA is used to represent the concrete properties. The SHPB test model is established and a few stress waves are applied to the incident bar to simulate the dynamic concrete behaviors. The stress-strain curves are obtained. The stress distributions are analyzed. The crack initiation and propagation process are described. It is concluded that: the HJC model can modeling the entire process of the fracture initiation and fragmentation; the compressive of the concrete is significantly influenced by the strain rates.

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Authors and Affiliations

H.M. An
L. Liu
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Abstract

Accurate prediction of blasting vibration should be achieved in mine blasting production practice. It is also a critical problem in the field of blasting vibration control technology research. In this research paper, on the basis of the previous research results and taking account into the reflection principle of elastic wave at the free interface, the authours proposes the blasting seismic wave propagation model. In addition, the blasting positive elevation effect are theoretically explained in detail, and the vibration velocity prediction formula of the positive elevation effect is derived. Finally, the positive elevation effect mechanism and the step (positive) formula are calibrated based on the on-site monitoring data of blasting vibration of Qipanjing Jinou coal mine. In beirf, a theoretical basis is laid by this paper for similar blasting projects.
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Authors and Affiliations

X.J. Zhang
1
H.M. An
2

  1. School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China
  2. Kunming University of Science and Technology, Faculty of Public Security and Emergency Management, 650093, Kunming, China
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Abstract

A testbench is built to verify a functionality of a shift register IC (Integrated Circuit) from stuck-at-faults, stuck-at-1 as well as stuck-at-0. The testbench is supported by components, i.e., generator, interface, driver, monitor, scoreboard, environment, test, and testbench top. The IC consists of sequential logic circuits of D-type flip-flops. The faults may occur at interconnects between the circuits inside the IC. In order to examine the functionality from the faults, both the testbench and the IC are designed using SystemVerilog and simulated using Questasim simulator. Simulation results show the faults may be detected by the testbench. Moreover, the detected faults may be indicated by error statements in transcript results of the simulator.
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Authors and Affiliations

Widianto
1
H.M. Chasrun
1
Robert Lis
2
ORCID: ORCID

  1. University of Muhammadiyah Malang, Department of Electrical Engineering, Indonesia
  2. Wroclaw University of Science and Technology, Poland
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Abstract

Helicobacter pullorum ( H. pullorum) is a bacterium that colonizes the intestines of poultry and causes gastroenteritis. Because these species are known as human and/or animal pathogens, identification of H. pullorum is becoming increasingly necessary. The bacterium has been linked to colitis and hepatitis in humans after being transmitted by infected meat consumption. Misdiagnosis of other enteric zoonotic pathogens such as Campylobacter and other Helicobacter species makes the diagnosis of H. pullorum extremely difficult. This study focused on the molecular detection of H. pullorum from the stomach (proventriculus and gizzard) of different avian species as new target organs for detection and transmission between avian species. Proventriculus and gizzards were obtained from 40 freshly dead chickens and resident wild birds (n=40). Diarrhea was found in the farms that were surveyed. DNA was extracted from all collected samples to conduct PCR amplification. The samples were screened for Helicobacter genus-specific 16s using C97 and C05 primers. To confirm the existence of H. pullorum, the positive samples were sequenced.
H. pullorum was recorded in two out of 40 chicken samples. In addition, H. pullorum was recorded in one out of 40 resident wild birds. The 16S rRNA gene sequence for Helicobacter genus-specific in poultry and wild birds showed a 100% homology. In conclusion, broiler chickens and resident wild birds are possible reservoirs for H. pullorum, according to this report, and possibly act as a source of infection for humans via the food supply.
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Bibliography

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Authors and Affiliations

R. Elhelw
1
M. Elhariri
1
H.M. Salem
2
H.S. Khalefa
3
D.A. Hamza
4
Z.S. Ahmed
4

  1. Department of Microbiology, Faculty of Veterinary Medicine, Cairo University, Egypt
  2. Department of Poultry Diseases, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
  3. Department of Veterinary Hygiene and Management, Faculty of Veterinary Medicine, Cairo University, Egypt
  4. Department of Zoonoses, Faculty of Veterinary Medicine, Cairo University, P.O. Box 12211, Giza, Egypt
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Abstract

Salmonella contamination in poultry feed is one of the main issues in poultry industry and public health. The aim of the present study was molecular detection and typing of Salmonella serotypes isolated from poultry feeds. Moreover, we determined the antibiotic resistance pattern and the ability of biofilm formation in the serotypes. To this end, eighty feed samples were collected from aviculture depots. Salmonella serotypes were identified by culture and PCR methods. For serological identification, a slide agglutination test was used. BOXAIR and rep-PCR methods were applied to evaluate the diversity of serotypes. The disc diffusion method was performed to evaluate the antibiotic susceptibility of serotypes to sixteen antibiotics. Biofilm formation was also assessed by the microtiter-plate test. From a total of 80 feed samples, 30 samples were contaminated with Salmonella spp., which were divided into 5 different serotypes belonging to B, C, and D serogroups. BOXAIR-PCR (D value [DI] 0.985) and rep-PCR (DI 0.991) fingerprinting of isolates revealed 23 and 19 reproducible fingerprint patterns, respectively. A higher antibiotic resistance was observed to ampicillin and doxycycline (100% each), followed by chloramphenicol (83.33%) and tetracycline (73.33%). Multidrug resistance (MDR) was detected in all Salmonella serotypes. Half of the serotypes possessed the ability of biofilm formation with varied adhesion strengths. These results revealed the high and unexpected prevalence of Salmonella serotypes in poultry feed with MDR and biofilm formation ability. BOXAIR and rep-PCR revealed a high diversity of Salmonella serotypes in feeds and subsequently indicated variation in the source of Salmonella spp. The unknown sources harboring high diversity of Salmonella serotypes indicated poor control, which could cause problems for feed manufacturing.
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Authors and Affiliations

G. Shahbazi
1
J. Shayegh
1
C. Ghazaei
2
M.H.M. Ghazani
1
S. Hanifian
3

  1. Department of Veterinary Medicine, Faculty of Veterinary and Agriculture, Shabestar Branch, Islamic Azad University, Shabestar, Iran
  2. Department of Microbiology, University of Mohaghegh Ardabili, Ardabil, Iran
  3. Department of Food Science and Technology, Biotechnology Research Center,Tabriz Branch, Islamic Azad University, Tabriz, Iran
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Abstract

The concrete-filled section of columns has been widely in construction used due to its structural elements. As a result, the usage of composite columns has recently increased all over the world. However, using foamed concrete alone does not result in much improvements in strength. Therefore, this paper examines the use of foamed concrete containing fibre to improve the strength of composite columns. Specifically, this study aims to determine the bond strength of concrete-filled hollow section (CFHS) with modified fibrous foamed concrete. Two types of fibre are used in this work, namely, steel fibre and polypropylene fibre, with rice husk ash (RHA) as a sand replacement to improve the compressive strength of foamed concrete. The CFHS with modified fibrous foamed concrete is tested by using the push-out method, and the results show that CFHS with steel fibre has a highest bond strength.

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Authors and Affiliations

S.A.A. Khairuddin
N.A. Rahman
N. Jamaluddin
Z.M. Jaini
A. Elamin
R.H.M. Rum
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Abstract

Water contamination that caused by heavy metals is a very common phenomenon in the industrial age. One of the popular way to treat metal contaminated water is by adsorption process using activated carbon as the adsorbent. This paper works on producing activated carbon by chemical means with impregnation ratios of NaOH:char (w/w) was predetermined at 1:1 (ACT1-1), 2:1 (ACT2-1) and 3:1 (ACT3-1) under activation temperature of 700°C. Considering the Leucaena leucocephala is a wildly, easy and fast grown species, with the availability throught the year, it was chosen to be used as the precursor. The properties of these activated carbons and its potential for cadmium removal from aqueus solution was analyzed. It was found that the highest surface area was recorded at 662.76 m²/g. Four parameters were studied which are contact time, the effect of pH, initial concentration of adsorbate and temperature. The equilibrium time was achieved in 40 min treatment at initial concentrations of 30 mg/l. The adsorbent exhibited good sorption potential for cadmium at pH 8.0 and equilibrium temperature of 30℃. Based on the results, this study had proved that activated carbon from Leucaena leucocephala biomass have the good potential to be used for removal of cadmium from wastewater.
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Authors and Affiliations

W.M.H.W. Ibrahim
1
N.S. Sulaiman
2
M.H.M. Amini
1
W.R.A. Kadir
3
M. Mohamed
1
S.F.M. Ramle
1
U. Bilgin
4
W. Rahman
5 6

  1. Universiti Malaysia Kelantan, Faculty of Bioengineering and Technology, Jeli Campus, 17600 Jeli, Kelantan, Malaysia
  2. Universiti Sains Malaysia, School of Industrial Technology, 11800 Minden, Penang, Malaysia
  3. Forest Research Institute Malaysia, 52109 Kuala Lumpur, Selangor, Malaysia
  4. Karadeniz Technical University, Faculty of Forestry, 61080 Trabzon, Turkey
  5. Universiti Malaysia Perlis, Faculty of Mechanical Engineering Technology, Perlis, Malaysia
  6. Universiti Malaysia Perlis, Center of Excellence Geopolymer and Green Technology (CEGeoGTech), Perlis, Malaysia

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