Petroleum and Minerals Department of Mechanical Engineering / University of Pittsburgh / Fahd University of Petroleum / OF HELMHOLTZ RESONATORS IN ONE AND TWO DEGREES OF FREEDOM FOR NOISE ATTENUATION IN PIPELINES S. Mekid and M. Farooqui King Fahd University of Petroleum / Acoustical Society of America / UK Institute of Acoustics / Association of Australian Acoustical Consultants / / /