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Number of results: 8
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Performance evaluation of ZVS/ZCS high efficiency AC/DC converter for high power applications

A. Ali J. Chuanwen M.M. Khan S. Habib Y. Ali
Bulletin of the Polish Academy of Sciences Technical Sciences | 2020 | 68 | No. 4 (i.a. Special Section on Advances in Electrical Power Engineering) | 793-807 | DOI: 10.24425/bpasts.2020.134185
Keywords switching loss zero current switching zero voltage switching power quality reverse recovery loss
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Abstract

The increased power density, reduced switching losses with minimum electromagnetic interference (EMI), and high efficiency are essential requirements of power converters. To achieve these characteristics, soft power converters employing soft switching techniques are indispensable. In this paper, a ZCS/ZVS PWM AC/DC converter topology has been emphasized, which finds applications in high power systems such as automobile battery charging and renewable energy systems. This converter scheme maintains zero current and zero voltage switching conditions at turn on and turn off moments of semiconductor switches, respectively and soft operation of rectifier diodes that lead to negligible switching and diode reverse recovery losses. Moreover, it improves power quality and presents high input power factor, low total harmonic distortion of the input current (THDI) and improved efficiency. The validity of theoretical analysis of the proposed converter has been carried out experimentally on a 10 kW laboratory prototype. Experimental results prove that the soft switching operation of the semiconductor switches and diodes is maintained at 98.6% rated load efficiency. In addition, the performance evaluation has been performed by comparative analysis of the proposed converter with some prior art high power AC/DC converters. Efficiencies of the proposed and prior art high power topologies have been determined for different load conditions. The highest efficiency, power factor and lower THDI of the proposed converter topology complies with international standards.

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Authors and Affiliations

A. Ali
J. Chuanwen
M.M. Khan
S. Habib
Y. Ali

Molecular epidemiology and phylogenetic analysis of Tams I gene of Theileria annulata in Khyber Pakhtunkhwa, Pakistan

S.S.A. Shah U. Saddique M.A. Khan S. Khan
Polish Journal of Veterinary Sciences | 2022 | vol. 25 | No 4 | 625-629 | DOI: 10.24425/pjvs.2022.143543
Keywords crossbred cattle Pakistan PCR risk factors sequencing theileriosis
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Abstract

Theileriosis is a hemoparasitic disease that affects a wide range of different animal species and is caused by various species of Theileria. This study aimed to determine the molecular epidemiology of Theileria annulata through microscopy and PCR, in crossbred cattle in some districts of Khyber Pakhtunkhwa, Pakistan. For this study, a total of 384 blood samples were collected from cattle in the Peshawar (n=120), Charsadda (n=94), Nowshera (n=84), and Swabi (n=86) districts. Microscopy and PCR were used to determine the overall prevalence of theileriosis, which was found to be 15.8 and 22.6%, respectively. Theileria annulata was detected in blood samples through PCR in the study area, and the target gene i.e., Tams 1, of positive samples was sequenced. The sequences in the current study revealed high sequence homology (ranging from 96 to 100%) with Tams 1 sequences of neighboring countries present in the NCBI database. Season, breed, age, and sex were found to be important risk factors among the several risk factors examined, whereas, among different clinical manifestations, lymphadenopathy showed a strong association with theileriosis. According to Cohen’s kappa and ROC analysis, microscopy was proven to be a fair diagnostic test for detecting theileriosis in cattle, and may be used in combination with molecular techniques for screening a large number of animals.
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Authors and Affiliations

S.S.A. Shah
1 2
U. Saddique
1
M.A. Khan
1
S. Khan
1
  1. College of Veterinary Sciences, Faculty of Animal Husbandry and Veterinary Sciences, The University of Agriculture, Peshawar, 25130, Khyber Pakhtunkhwa, Pakistan
  2. Veterinary Research Institute, Peshawar-Pakistan

Comparative evaluation of different techniques for herniorrhaphy in calves

A. Fatima M. Arif Khan S. Aslam K. Ashraf A. Khalid Mahmood M. Asif S. Shah N. Hussain
Polish Journal of Veterinary Sciences | 2022 | vol. 25 | No 2 | 207-212 | DOI: 10.24425/pjvs.2022.141804
Keywords calves mesh application suture material umbilical hernia
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Abstract

Umbilical hernia is one of the most common problems in young calves. This problem occurs in dairy sector as well as in the local farmers. Present study was conducted to compare outcomes of four different techniques of herniorrhaphy. Twenty four young calves (n=24) were divided in 4 groups (A, B, C, and D) which underwent four different surgical techniques. Group A underwent vicryl plus suture material and pants-over-west technique, Group B underwent mesh application with Dexon suture material by using simple interrupted suture pattern, Group C underwent closed method with Nylon No. 3 suture material by using vertical mattress suture pattern and Group D underwent clamp application method with Silk No. 2 suture material by using simple interrupted suture pattern. The result showed that mesh application method was comparatively better with respect to feed intake, body weight gain and healing time. There was no reoccurrence with non-significant hematological changes (p≤0.05). It is concluded that mesh application method is safer than other three techniques and there are no systemic effects of this surgical intervention on calves’ health.
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Authors and Affiliations

A. Fatima
1
M. Arif Khan
1
S. Aslam
1
K. Ashraf
2
A. Khalid Mahmood
1
M. Asif
1
S. Shah
1
N. Hussain
1
  1. Department of Veterinary Surgery and Pet Sciences, University of Veterinary and Animal Sciences, Out fall road 54000, Lahore-Pakistan
  2. Department of Parasitology, University of Veterinary and Animal Sciences, Out fall road 54000, Lahore-Pakistan

A new scheme for power factor correction and active filtering for six-pulse converters loads

Y. Han M. Khan L. Xu G. Yao L. Zhou C. Chen
Bulletin of the Polish Academy of Sciences Technical Sciences | 2009 | vol. 57 | No 2 | 157-169 | DOI: 10.2478/v10175-010-0117-0
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Authors and Affiliations

Y. Han
M. Khan
L. Xu
G. Yao
L. Zhou
C. Chen

Thermal and acoustic behavior of energy saving wall panel

M. Yasir Khan Abdul Baqi Rehan Sadique
Archives of Civil Engineering | 2021 | vol. 67 | No 4 | 303-316 | DOI: 10.24425/ace.2021.138501
Keywords sustainable building sandwich structures structural insulated panels building thermal performance acoustic absorption
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Abstract

Research and development of energy-efficient materials have been essential for sustainable infrastructure growth. A considerable amount of money is being spent on various energy stabilization techniques worldwide to attain thermal comfort in buildings. Thus, lowering the energy demand through green materials is vital to save energy and the environment. In this paper, a new form of Structural Insulated Panel (SIP) has been developed and referred to as Ferro Cellular Lightweight Concrete Insulated Panel (FCIP). Comparative thermal efficiency and acoustic performance of FCIP and brick masonry walls have been tested experimentally. The thermal results show that FCIP allows just 2 deg C rise in the internal temperature of the room chamber in two hours, whereas the brick masonry allows 9.5 deg C rise in the internal temperature of the room chamber for the same period. Similarly, the acoustic results show that FCIP has 0.85 sound absorption coefficient compared to 0.2 for brick masonry wall. Further, the cost-benefit analysis was conducted based on the electricity consumption results of a building produced by the eQuest energy simulation program. The outcome shows that the building’s lifetime running cost gets reduced to 50% when FCIP replaces the concrete/brick masonry envelope.
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Authors and Affiliations

M. Yasir Khan
1
ORCID: ORCID
Abdul Baqi
1
ORCID: ORCID
Rehan Sadique
1
ORCID: ORCID
  1. Dept. of Civil Engineering, Aligarh Muslim University, Aligarh, India

Comparative Efficacy of Silymarin and Choline Chloride (Liver Tonics) in Preventing the Effects of Aflatoxin B1 in Bovine Calves

O. Naseer J.A. Khan M.S. Khan M.O. Omer G.A. Chishti M.L. Sohail M.U. Saleem
Polish Journal of Veterinary Sciences | 2016 | No 3 | DOI: 10.1515/pjvs-2016-0068
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Authors and Affiliations

O. Naseer
J.A. Khan
M.S. Khan
M.O. Omer
G.A. Chishti
M.L. Sohail
M.U. Saleem

Assessing Machinability and Surface characteristics of a Shape Memory Alloy (SMA) Processed through Wire Electro Spark Erosion Method

Ebenezer George Adam Khan M. Chellaganesh Duraipandi Winowlin Jappes J.T. Julfikar Haider
Archives of Metallurgy and Materials | 2022 | vol. 67 | No 3 | 921-930 | DOI: 10.24425/amm.2022.139684
Keywords Wire Electro Spark Erosion Machining NiTi alloy Surface roughness Material removal rate (MRR)
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Abstract

In this paper, a study was carried out to investigate the surface roughness and material removal rate of low carbon NiTi shape memory alloy (SMA) machined by Wire Electro Spark Erosion (WESE) technique. Experiments are designed considering three parameters viz, spark ON time (SON), spark OFF time (SOFF), and voltage (V) at three levels each. The surface roughness increased from 2.1686 μm to 2.6869 μm with an increase in both SON time, SOFF time and a decrease in voltage. The material removal rate increased from 1.272 mm3/min to 1.616 mm3/min with an increase in SON time but a varying effect was observed the SOFF time and voltage were varied. The analysis revealed that the intensity and duration of the spark had an unswerving relation with the concentration of the microcracks and micropores. More microcracks and micropores were seen in the combination of SON = 120 µs, voltage = 30 V. The concentration of the microcracks and micropores could be minimised by using an appropriate parameter setting. Therefore, considering the surface analysis and material removal, the low carbon NiTi alloy is recommended to machine with 110 μs – 55 μs – 30 v (SON – SOFF – V respectively), to achieve better surface roughness with minimal surface damage.
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Authors and Affiliations

Ebenezer George
1
ORCID: ORCID
Adam Khan M.
1
ORCID: ORCID
Chellaganesh Duraipandi
1
Winowlin Jappes J.T.
1
Julfikar Haider
2
  1. School of Automotive and Mechanical Engineering and Centre for Surface Engineering, Kalasalingam Academy of Research and Education, Tamil Nadu, India
  2. Manchester Metropolitan University, Advanced Materials and Surface Engineering (AMSE) Research Centre, Chester Street, M1 5GD, UK

Investigations on Mechanical Properties of Bio-Waste Micro Particles Reinforced Phenol Formaldehyde Composites

A. Sujin Jose A. Athijayamani S.P. Jani V. Mago Stalany M. Adam Khan
Archives of Metallurgy and Materials | 2022 | vol. 67 | No 1 | 377-384 | DOI: 10.24425/amm.2022.137768
Keywords Wood Sawdust Particles Coir Pith Particles Hybrid Composites Mechanical Properties The rule of Mixture Method
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Abstract

A characteristic study on the phenol formaldehyde (PF) composite is carried out based on the micro level bio waste particles such as wood sawdust (WSD) and coir pith (CP). Composite is characterized by mechanical properties such as tensile, flexural and impact at different percentages of particles (0-50% by weight) to find out the optimum percentage of particle loading to get the maximum properties. The WSD/CP/PF hybrid composite is also prepared by two different methods i.e., one: one (1:1) ratio and rule of mixture. The first method (1:1) is used to find out the optimum level of hybrid particles loading to get the maximum properties. But, the second method is followed to find out the weight percentages of particles influencing the properties of resulting composite. The results show that the mechanical properties of WSD/PF are higher than CP/PF composite in the entire particle loading. The optimum particle loading to get the maximum properties is 40 wt.% in CP/PF composite, whereas for WSD/PF composite are at 30 wt.%. The hybrid composite (1:1) also gives the maximum properties at 30 wt.%. Moreover, the hybrid composite (20WSD/10CP) prepared by rule of mixture showed the highest mechanical properties compared to the other particle loading. It is identified that the WSD particles are most influencing the properties of PF composites than the CP particles. Fractographic study was performed using scanning electron microscope to examine the failure mechanism of the composite specimens.
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Authors and Affiliations

A. Sujin Jose
1
ORCID: ORCID
A. Athijayamani
2
ORCID: ORCID
S.P. Jani
3
ORCID: ORCID
V. Mago Stalany
4
ORCID: ORCID
M. Adam Khan
5
ORCID: ORCID
  1. Automobile Engineering, New Horizon College of Engineering, Bengaluru, India
  2. Mechanical, Government College of Engineering, Bodi, Tamil Nadu, India
  3. Department of Mechanical Engineering, Marri Laxman Reddy Institute of Technology and Management, Hyderabad – 500043, India
  4. Mechanical, Lourdes Mount College of Engineering & Technology, Marthandam, Ta milnadu, India5
  5. School of Automotive and Mechanical Engineering, Kalasalingam Academy of Research & Education, Virudhunagar Dist., Tamilnadu, India

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