Publications

a) Books Co-author of the book "Interferometry of Fibrous Materials" in collaboration with Professor Dr. N. Barakat of Ain Shams University, Published by Adam Hilger International Series on Optics and Optoelectronics, Adam Hilger IOP Publishing Ltd.,England (January 1990). This book describes the applications of interferometry to natural, synthetic and optical fibres.   Dr. Ahmed Amin Hamza took part in the translation and review of the fifth edition of the book physics for Scientists and Engineers with modern physics by Raymond A. Serway, Robert J. Niechner and John W. Jewett, Jr. This book was translated over four volumes with forty six chapters by Prof. Ahmed Hamza, Prof. Mohamed Mahmoud Ammar, Prof. Taha Zaki Sokkar, Prof. Salah Kamel El Labany and Prof. Mohamed AbdelFattah Mabrouk b) Scientific Papers I published over 150 papers in Scientific Journals in the fields of Interferometry, Fibre Optics, Colour Measurement, Polymer Physics and Fibre and Textile Physics. Many of these papers have been cited in scientific Journals and textbooks in the related fields. The following summary presents the topics, studies and the methods used by Prof. Hamza and co-workers in the fields of fibre optics, colour physics and spectroscopy for over than thirty years. Refer to the papers in the attached list of publications from No.1 to No. 102.

 

STUDIES OF
SOME PHYSICAL PROPERTIES OF FIBRES

AND THEIR ASSEMBLIES
2001

Forward

• Professor Ahmed Amin Hamza was graduated from Ain-Shams University, Faculty of Science. He was awarded his M.Sc. and Ph.D. in Optics from Faculty of Science, Ain-Shams University. He worked in Mansoura University since 1972. Through a period of about three decades, he established a research group in Mansoura University.

• Professor Hamza established also two research groups; one in the Faculty of Science in Demietta, a branch of Mansoura University, and the other group in the Faculty of Engineering, Mansoura University. He was head of the Physics Department, Faculty of Science from 1984 to 1986, Vice-Dean of the Faculty of Science, Mansoura University from 1986 to 1992, Vice- President for Community and Environmental Development, University of Mansoura from 1992 to 1994 and President of Mansoura University from 1994 till July 2001. He is a Fellow of the Institute of Physics (C. Phys. F. Inst. P.) (London), Fellow of the Royal Microscopical Society (FRMS) (Oxford) and Member of the International Society for Optical Engineering (SPIE).

• The following are the scientific contributions of Prof. Hamza and his co-workers in the fields of fibre optics, colour physics and spectroscopy, for over than thirty years. Refer to the papers in the attached list of publications from No. 1 to No. 102.

Interferometric Studies on Fibres

• The physical properties of fibres are determined by their structure. In case of textile fibres, for example, its clear understanding (starting from the molecular level of organization) is of paramount importance in the continuing efforts to rationalize:

  • Production, including the development of scientific methods of quality control at all stages of cultivation, as in the case of cotton (an important product in Egyptian economy).

  • Spinning of the synthetic or regenerated fibres.

   

• Characterization of optical fibres is an important task for many reasons. The designers of optical fibre systems need to know the fibre characteristics to design these systems. Optical fibre manufactures need these information for optimizing their fabrication processes to obtain fibres with these characteristics.

   

• The produced data are necessary for the development and verification of theoretical models that predict the performance properties of the fibre.

   

• Two-and multiple-beam interferometric techniques are very powerful tools for the determination of the optical properties of these fibres and therefore are suitable for fibre characterization.

   

• The following summary presents the topics studies and the methods used, in a somewhat arbitrary way :

( I ) Textile fibres Investigation

• Structural anisotropy: optical and X-ray methods.

• Some physical characteristics of single fibres and their assemblies.

• Colour matching and dying.

• Spectroscopy.

• Scanning electron microscopy; both qualitative and quantitative.

• Opto-mechanical properties of fibres.

• Effect of radiation on fibres optical parameters.

• Opto-thermal properties of fibres.

( II ) Optical Waveguides

• Optical fibre profiling of (GR-IN type).

• Refractive index profile parameters.

• Optical and geometrical parameters affecting the fibre com-munication efficiency.

( III ) Techniques and Methods

• Forward scattering technique.

• Multiple-beam interference technique.

• Two-beam interference technique.

• Opto-mechanical system.

• Opto-thermal technique.

• Variable wavelength microinterferometric technique.

• Optical Forier Transform (OFT) technique.

( IV ) Theoretical approaches developed

• Multi-layer assumption using distance and area measurements.

• Determination of the index profiles taking into consideration the area under the fringe shift.

• Determination of refractive index profile considering the refraction of the incident beam inside the fibre.

• Determination of the refractive index profile of highly oriented fibres.

( V ) Image analysis systems

• Variable wavelength system.

• Multiple-beam Fizeau fringes analysis.

N.B.: The number of references in the following text refers to the papers cited in the attached list of publications.

( I ) Textile Fibre Investigation

1. Structural Anisotropy

A- Optical anisotropy; optical and X-ray methods

• Assessment of the optical anisotropy of fibres is of considerable importance since it provides information about the degree of orientation in a particular molecular system, making possible evaluation of the effect of either chemical or mechanical treatments; knowledge of the kind being of great relevance in the development of the modern methods of quality control in many industrial processes.

• An investigation was opened into the so far unexplored problem of theoretical calculations of the optical anisotropy of some different kinds of fibres. The principal polarizabilities of an aromatic poly (P-phenylene terephthalmide) fibres (Kevlar fibres) were calculated using the known values of bond polarizabilities together with the Lorentz-Lorenz (additive) expression to derive the principal refractive indices (and the birefringence) of these fibres. The discrepancy between so calculated and the measured values (using the Pluta polarizing interference microscope) were discussed (13).

• A new method was also presented to measure the mean refractive indices and the birefringence of fibres of irregularly shaped transverse sections, by the complementary use of the interference and scanning electron microscopy. The method was applied to the measurement of the optical anisotropy of cotton fibres (18).

B- X-ray methods

The X-ray methods were used to examine the orientation (and size) of the crystallites in cotton fibres.

2. Some Physical Characteristics of Single Fibres and their Assemblies

1. Single fibres

   A convenient method for measuring the diameter of fibres by observing the diffraction pattern of a He-Ne laser beam incident perpendicular to the fibre axis. The method was used for the determination of fibre cross-sectional area and shape (19, 20, 22 and 23).

    

2. Fibrous Assemblies

   A spectrometer was employed to measure the number of threads per unit length in fabrics, simultaneously in the direction of warp and weft (8).

3. Colour matching and dyeing

Methods of colorimetry were applied to the study of :

1. The effect of some bleaching techniques of dyed cotton textile materials (1),

2. Fastness of dyes to light (10, 11 and 17),

3. Cotton reflectance relations to the content of metallic impurities (3),

4. Effect of finishing treatment (with a variety of compounds) on calorimetric properties of dyed polyester/cotton blends (10 and 11),

5. Brightness of Egyptian cotton fibres (26),

6. Determination of spectral reflectance curves of dyed fabrics on the basis of the value of refractive indices of fibres and spectral absorption curves of used dyestuff (72).

4. Spectrometry

• Quantitative spectrometric estimates of trace elements in some varieties of Egyptian cotton fibres were carried out and a relation was suggested between the quantities of these elements and their effect on the structural and mechanical properties (2).

5. Scanning electron microscopy; both qualitative and quantitative
    

   • Since the scanning electron microscope is particularly suited to the observation of dynamic experiments within its specimen chamber a review of the available methods was undertaken (12). The frictional properties of Egyptian cotton fibres were studied using simultaneously a videotape recorder coupled with a device for measuring both the normal and tangential forces (14).

   • The surface topography and ultrafine structure of several varieties of virgin and chemically treated Egyptian cotton fibres, together with the orientation and crystalline size (of X-ray methods) was compared with the staple length and tenacity of these fibres(16).

    

6. Opto-mechanical properties of fibres
    

   • A device was designed to help in studying the opto-mechanical properties of fibres (46 and 47). The change in optical properties of textile fibres can be studied easily using this machine. Now, one can use it to stretch the fibre along its axis and/or twist it in situ during experimental measurements. These processes were applied for the characterization of different textile fibres. (46,47,51,63,64, 67-69 and 88).

    

7. Effect of radiation on the fibre optical properties

8. Opto-thermal properties of fibres

• Opto-thermal properties of textile fibres were studied in details. The effect of fibre annealing on the birefringence and on optical and dynamic mechanical parameters of different fibres were studied and reported in some publications (50, 79, 83-87, 89-94 and 100).

( II ) Optical fibre Characterization

1. Optical fibre profiling (GR-IN type) (32)

• The importance of the optical fibres and waveguides are due to its wide use in industry, applied optics and opto-electronics. Prof. Hamza and co-workers used the interference techniques to study the optical fibre properties especially these used in telecommunications.

• Different theoretical formulae were developed by Prof. Hamza and co-workers to modify the measurement accuracy of different types of optical fibres whose core has a graded index structure (65, 70 and 80).

• Refractive index profiles of fibres such as, graded index multi-mode and single and multi-modes step index fibres (95) were measured. Different expressions were modified and used to measure the profile shape parameter and the core/cladding refractive index difference.

2. Refractive index profile parameters

• A study of the refractive index profile parameters as the profile shape parameter a which determine the optical fibre refractive index profile shape was considered using different methods. The value of D n, which is the core-cladding refractive indices difference for different types of fibres, was calculated. Both a and D n plays an important role in determining the refractive index profile of optical fibres (see 32, 65, 70 and 80).

3. Optical and geometrical parameters affecting the fibre communication efficiency

• In addition to the profile shape parameter a and the core/cladding refractive index difference D n of graded index fibres, the refractive index profile and the fibre core diameter are important parameters to determine the optical fibre performance. In this area, some papers were published.

( III ) Techniques and Methods

1- Diffraction technique

• A simple technique based on the diffraction of the laser beam on a fibre mounted vertically, produce a horizontal pattern. This pattern is used to calculate the fibre diameter, shape and cross-sectional area of the fibre (textile and homogenous fibres only).

2- Multiple-beam interference technique

• Multiple-beam interference of the Fizeau type pattern is used to measure accurately the refractive index and birefringence of both textile and optical fibres. The interference fringe shift in the fibre region can be used to determine the mean refractive index or the refractive index profile for symmetrical-cylindrical fibres. The area enclosed under the interference fringe shift is used to determine the refractive index profile if the fibre has irregular cross-sectional shape.

• In this case this area represents the optical path difference integrated across the whole cross – sectional area of the fibre.

• Taking the refraction of the light beam crossing the fibre into consideration, the measurement accuracy increased. In fact, multiple-beam interference method used to determine the refractive index profile is one of the most accurate techniques. Herein, most of Prof. Hamza’s publications concerns this technique.

3- Two-beam interference technique

• Pluta microscope is a double-refracting interference microscope with variable amount and direction of wavefront shear. It is capable of giving either the uniform or fringe interference fields with continuously variable amount and direction of lateral image duplication. Hamza in 1980 extended the application of the Pluta microscope to measure the mean refractive indices and birefringence of fibres with irregular transverse section (18).

4- Opto-mechanical system

• In 1987, Hamza and co-workers designed an instrument used with the multiple-beam Fizeau system to stretch longitudinally (or twist) textile fibres. They used it to study the opto-mechanical properties of textile fibres (see 46, 51, 53, 64, 67, 68, 82 and 88).

5- Opto-thermal technique

• Using a chamber that contains a single set up to regulate the temperature of the sample via a thermostat whose thermocouple ends close to the sample. This unit can be used with an interferometric system. A regular increase of the temperature can be obtained and hence, the change in the optical properties of the fibre due to temperature change can be determined interferometrically (100).

6- Variable wavelength technique

• The variable wavelength interferometry (VAWI) is a method used in textile fibre investigation. It has the advantage that it can be used to measure the refractive indices and birefringence as well as the material dispersion of fibres especially those having refractive indices greater than 1.7.These fibres could not be easily investigated using other methods.(97-98).

( IV ) Theoretical approaches developed

Hamza and co-workers developed many theoretical approaches which are used in both optical and textile fibre investigations. Herein, a summary of these studies:

1- Multi-layer assumption

1. Determination of the refractive index along the radius of a multilayer structure fibre using the distance method:

• Theoretical expressions were derived and used to measure the refractive indices and birefringence using interference fringe shift in the fibre region. The derived formulae were applied experimentally (see ref. 30, 36 and 65).

2. Refractive index determination of multilayer fibre using the area enclosed under the fringe shift

• The area enclosed under the interference fringe shift in the fibre region is used to determine the refractive indices and birefringence of fibres with irregular cross-section, see ref. (18, 31, 33, 35, 37, 47, 49, 58, 60 and 76).

3. Determination of the index profile taking into consideration the area under the fringe shift

• The area enclosed under the fringe shift is used to obtain the refractive index profile of optical and textile fibres. The expressions were derived to overcome the errors due to the fibre irregularity (65).

4. Determination of the refractive index profile considering the refraction of the incident beam inside the fibre

• A mathematical expression that relates the fringe shift at a point along the radius to the fibre geometrical distances was derived. This was done considering the optical path of the refracted beam inside the fibre. These expressions were used to overcome the errors in calculating the refractive index profile in mulilayer fibres (73, 77 and 80).

( V ) Image analysis system

1. Variable wavelength system

    

   • The variable wavelength interference technique is attached with a computer via a CCD camera and frame grabber digitizer to form a system used in automatic interference fringes analysis. This system offers both accurate and fast measurements. See ref. 97 and (98).

    

2. Multiple-beam Fizeau fringes analysis

• Multiple-beam interference of the Fizeau type is used with the aid of a computer to determine automatically the optical properties of fibres. The system set up, hardware maintenance and software were prepared by the optics group of Demietta Faculty of Science, Mansoura University.

• Increasing efforts are made in attempting to apply the method for both optical and textile fibres in order to offer good accuracy and a fast way of measuring their optical properties (See ref. 101).

• The following is a list of publications of Prof. Ahmed A. Hamza from no.1 to no.130. The description of the work of the optics group at Mansoura University are referred in these publications.

List of Scientific Papers

 BY

Professor Dr. Ahmed Amin Hamza

1. Wassef, E.G.T. and Hamza, A.A.: "An application of colourimetry in a comparative study of the effects of some bleaching techniques on the final appearance of dyed cotton textiles". Proceedings of the Egyptian Academy of Sciences, 20, 119 (1966-67).

2. Barakat, N., Aly, I.S. and Hamza, A.A.: "The effect of trace elements in cotton fibres on their physical properties". Journal of Textile Institute, 66, 87 (1975).

3. Barakat, N., Aly, I.S. and Hamza, A.A.: "Cotton reflectance changed by metallic impurities". American Dyestuff Reporter, 36, May (1975).

4. Badawy, Y.K.?M., Hamza, A.A. and Sokkar, T.Z.N.: "Colour appearance matching on the basis of optical measurements". Mansoura Science Bulletin, 3, 229 (1975).

5. Badawy, Y.K.M., Hamza, A.A. and Sokkar, T.Z.N.: "Colour matching formulation and corrections". Mansoura Science Bulletin, 3, 241 (1975).

6. Wassef, E.G.T. and Hamza, A.A.: "Use of colour difference formulae in the study of the relationship between dyestuff concentrations and the final colour of dyed cotton fabrics". Proceedings of the Egyptian Academy of Sciences, 28, 13 (1975).

7. Barakat, N., Hamza, A.A. and Fouda, I.: "Interferometric determination of the refractive indices and birefringence of Egyptian Camel hair fibres". Egyptian Journal of Physics, 6, No. 2, 91 (1975).

8. Barakat, N., Hamza, A.A. and Fouda, I.: "Determination of number of threads per unit length in woven fabrics". Egyptian Journal of Physics, 6, No.2, 119 (1975).

9. Barakat, N., Aly, I.S. and Hamza, A.A.: "Target camouflage against detection by infrared radiations". Proceedings of the Mathematical and Physical Society of Egypt, No. 41, 65, January (1976).

10. Hebeish, A., Allam, E., Hamza, A.A., Shams, M. and Kamel, M.: "Effect of finishing with N-methylol compounds on the properties of dyed polyester/cotton blends". Kolorisztikai Ertesito, 308 (1976).

11. Hebeish, A., Allam, E., Hamza, A.A., Shams, M. and Kamel, M.: "Concurrent dyeing and finishing of polyester/cotton blend". Kolorisztikai Ertesito, 28 (1977).

12. Hamza, A.A.: "The present state of development of dynamic experiments in the specimen chamber of the scanning electron microscope". Proceedings of the Tenth Annual Scanning Electron Microscopy Symp., IIT Research Inst., Chicago, Illinois, vol.1, 703 (1977).

13. Hamza, A.A. and Sikorski, J.: "Optical anisotropy of poly (p-phenylene terephthalamide) fibres". Journal of Microscopy, 113, 15 (1978).

14. Basu, S.C., Hamza, A.A. and Sikorski, J.: "The friction of cotton fibres": Journal of the Textile Institute, 69, 68 (1978).

15. Badawy, Y.K.M., Hamza, A.A. and Abd El-Kader, H.I.: "Application of Interferometric methods for the study of variation of the refractive indices of cuprammonium fibres with wavelength of light and temperature". Mansoura Science Bulletin, 7, 40 (1979). (Presented at the Royal Microscopical Society Symposium held at the University of Leeds, England, March, 1977).

16. Hamza, A.A. and Kantouch, A.: "A comparative study of some different Egyptian cotton varieties". Bulletin of the National Research Centre, Egypt, 4, 7, (1979).

17. Hamza, A.A.: "Fastness of dyes to sunlight". Mansoura Science Bulletin, 7, 93 (1979).

18. Hamza, A.A.: "A contribution to the study of optical properties of fibres with irregular transverse section". Textile Research Journal, 50, 731 (1980).

19. Hamza, A.A., Fouda, I.M., El-Farhaty, K.A. and Badawy, Y.K.M.: "Production of polyethylene fibres and their optical properties and radial differences in orientation". Textile Research Journal, 50, 592 (1980).

20. Hamza, A.A., Fouda, I.M., El-Farhaty, K.A. and Badawy, Y.M.: "Optical properties of polypropylene fibres". Acta Physica Polonica, A58, 651 (1980).

21. Hamza, A.A., Fouda, I.M. and Hashish, A.H.: "A Comperative study of three methods used for the measurement of refractive indices and birefringence of polymer fibres". Acta Physica Polonica, A58, 657, (1980).

22. Hamza, A.A., Fouda, I.M. and Hashish, A.H.: "Graphical method for determining fibre cross-sectional shape". Egyptian Journal of Physics, 11, No. 2, 97 (1980).

23. Hamza, A.A., Fouda, I.M. and Hashish, A.H.: "Optical investigation of synthetic fibre properties". Egyptian Journal of Solids, 2, No.1, 126 (1980).

24. Fouda, I.M., Hamza, A.A., El-Niklawy, M.M. and El-Farahaty, K.A.: "Birefringence measurements on circular cylindrical polyethylene fibres of multiple skin". Textile Research Journal, 51, 355 (1981).

25. Hamza, A.A. and Sokkar, T.Z.N.: "Optical properties of Egyptian cotton fibres". Textile Research Journal, 51, 485 (1981).

26. Hamza, A.A. and Sokkar, T.Z.N.: "Brightness of Egyptian cotton fibres". Textile Research Journal, 51, 587 (1981).

27. Fouda, I.M., Hamza, A.A. and El-Farhaty, K.A.: "Measurement of refractive indices of polypropylene fibres by back-scattering techniques". Indian Journal of Textile Research, 6, 40 (1981).

28. Hamza, A.A., Fouda, I.M. and El-Farhaty, K.A.: "Optical path variations associated with multiple skin polypropylene fibre". Acata Physica Polonica, A61, 129 (1982).

29. Hamza, A.A. and Abd El-Kader, H.I.: "Optical properties and birefringence phenomenon in fibres". Textile Research Journal, 53, 205 (1983).

30. Hamza, A.A., Fouda, I.M., Hashish, A.H. and El-Farahaty, K.A.: "Measuring refractive indices and birefringence of multiple skin polymer fibres from their interference patterns". Textile Research Journal 54, 802 (1984).

31. Hamza, A.A., Sokkar, T.Z.N. and Shahin, M.M.: "Interferometric determination of the optical properties of fibres with irregular transverse sections (Ramie)". Journal of Microscopy, 137, 85 (1985).

32. Barakat, N., Hamza, A.A. and Goneid, A.S.: "Multiple-beam interference fringes applied to graded-index optical wave guides, for determination of fibre characterization". Appl. Opt. 24, 4383 (1985).

33. Hamza, A.A., Sokkar, T.Z.N. and Kabeel, M.A.: "Multiple-beam interferometric studies on fibres with irregular transverse sections". J. Phys. D: Appl. Phys., 18, 1773 (1985).

34. Hamza, A.A., Sokkar, T.Z.N. and Kabeel, M.A.: "Interferometric determination of optical properties of fibres with irregular transverse sections and having a skin-core structure". J. Phys. D: Appl. Phys. 18, 2321 (1985).

35. Hamza, A.A., Sokkar, T.Z.N. and Kabeel, M.A.: "Interferometric determination of refractive indices and birefringence of fibres with irregular transverse sections". J. Phys. D: Appl. Phys. 19, L19 (1986).

36. Hamza, A.A. and Kabeel, M.A.: "Multiple-beam fizeau fringes crossing a cylindrical fibre having multi-layers". J. Phys. D: Appl. Phys., 19, 1175 (1986).

37. Hamza, A.A.: "The Interferometric methods applied to the studies of fibrous materials". Journal of Microscopy 142, 35 (1986).

38. Hamza, A.A., and Abd El-Kader, H.I.: "Interferometric methods of measuring refractive indices and double refraction of fibres". Phys. Educ. 21, 244 (1986).

39. Hamza, A.A., Fouda, I.M. and El-Farhaty, K.A.: "Interferometric determination of Optical Properties of bicomponent fibres". Intern. J. Polymeric Mater., 11, 169 (1986).

40. Hamza, A.A. and El-Farhaty, K.A.: "Optical properties and geometrical parameters of poly (p-phbenylene terephthalamide) fibres". Textile Research Journal 56, 580 (1986).

41. Hamza, A.A., Ghander, A.H., Oraby, A.H., Mabrouk, M.A., and Guthrie, J.T.: "Effect of gamma irradiation on the optical properties of fibres". J. Phys. D: Appl. Phys., 19, 2443 (1986).

42. Hamza, A.A., Sokkar, T.Z.N. and Shahin, M.M.: "New colour difference formula and its comparison with some other formulae". Mansoura Science Bulletin 13, 563 (1986).

43. Hamza, A.A., Sokkar, T.Z.N. and Shahin, M.M.: "A proposal for new colorimetric functions and their relation with dyestuff concentrations". Mansoura Science Bulletin 13, 591 (1986).

44. Hamza, A.A. and Kabeel, M.A.: "Optical anisotropy in polypropylene fibres as a function of the draw ratio". J. Phys. D: Appl. Phys. 20, 963 (1987).

45. Hamza, A.A. and El-Dessouki, T.: "Structural parameters of polyester fibres from an Egyptian manufacturer".Textile Research Journal, 57, 508 (1987).

46. Hamza, A.A., Fouda, I.M., El-Farhaty, K.A. and Helaly, S.A.: "Stress birefringence in polypropylene fibres". Polymer Testing, 7, 329 (1987).

47. Hamza, A.A., Fouda, I.M. and El-Farhaty, K.A.: "Analysis of refractive index distributions in anisotropic polymeric fibres having regular and irregular transverse sectional shape". Textile Research Journal, 58, 35 (1988).

48. Hamza, A.A., Ghander, A.M., Oraby, A.H. and Mabrouk, M.A.: "Optical anisotropy in ion-beam irradiated fibres". J. Phys. D: Appl. Phys., 21, 407 (1988).

49. Hamza, A.A. and Mabrouk, M.A.: "Optical anisotropy in gamma irradiated fibres under vacuum". Radiat. Phys. Chem., 32, No.4, 645 (1988).

50. Hamza, A.A., Fouda, I.M., El-Farhaty, K.A. and El-Sayed, K.A.: "Effect of temperature on the birefringence variations of wool fibres". Acta Physica Polonica, A73, 767 (1988).

51. Hamza, A.A., El-Farhaty, K.A. and Helaly, S.A.: "Interferometric determination of opto-mechanical properties of fibres". Optica Applicata 18, No. 2, 133 (1988).

52. Hamza, A.A., Ghander, A.M. and Mabrouk, M.A.: "Interferometric studies on polymer structure". Radiat. Phys. Chem. 33, No.3, 231 (1989).

53. Hamza, A.A., Fouda, I.M., Kabeel, M.A. and Shabana, H.M.: "The optical behavior of polyethylene fibres with different draw ratio". Polymer Testing 8, 201 (1989).

54. Hamza, A.A., Kabeel, M.A. and Shahin, M.M.: "Interferometric studies on optical anisotropy and radial differences in orientation in polymer fibres". Textile Research Journal, 60, 157 (1990).

55. Hamza, A.A., Kabeel,M.A. and El-Said,A.M.:"Polymer reflectance changed by gamma irradiation". Radiat. Phys. Chem. 34, No.5, 797 (1989).

56. Hamza, A.A, Fouda, I.M., El-Farhaty, K.A. and El-Tonsy, M.M.: "Interferometric determination of the optical anisotropy of poly (P-oxybenzoate-co-p-phenylene isophthalae) 50/50 composition (POPI) fibres". Polymer Communications, 30, 186 (1989).

57. Hamza, A.A., El-Tonsy, M.M. and El-Labany, S.K.: "A contribution to the study of optical properties of cylindrical fibres". Polymer Testing, 8, 329 (1989).

58. Hamza, A.A. and Kabeel, M.A.: "Measurement of refractive indices of homogeneous fibres with regular or irregular transverse sections". Journal of Applied Physics, 68, 2639 (1990).

59. Soliman, M.A. and Hamza, A.A.: "Computerized analysis of microinterferograms of fibrous materials". Polymer Testing, 9, 169 (1990).

60. Hamza, A.A., Sokkar, T.Z.N., and Kabeel, M.A. : "Optical anisotropy in fibres with irregular cross-sections having a skin-core structure", Optica Applicate, 20, 253 (1990).

61. Hamza, A.A., Sokkar, T.Z.N., and Shahin, M.M.: "Interferometric determination of optical anisotropy in fibres, 1, homogeneous fibres". J. Appl. Phys. 69, 929 (1991).

62. Hamza, A.A., Sokkar, T.Z.N., and Shahin, M.M : "Interferometric determination of optical anisotropy in fibres, 2. fibres with a skin-core structure". J. Appl. Phys. 69, 7231 (1991).

63. Hamza, A.A., Fouda, I.M., El-Farhaty, K.A. and Seisa, E.A. : "Optomechanical properties of fibres, 1. optical anisotropy in stretched nylon 6-fibres". Polymer Testing, 10, 83 (1991).

64. Hamza, A.A., Fouda, I.M., El-Farhaty, K.A. and Seisa, E.A. : "Opto-mechanical properties of fibres, 2. optical anisotropy in polymer fibres as a function of the draw ratio". Polymer Testing, 10, 195 (1991).

65. Hamza, A.A. and Mabrouk, M.A. : "A multiple-beam interferometric method for refractive index determination of graded optical fibres". Journal of Modern Optics, 38, 97 (1991).

66. Hamza, A.A., Sokkar, T.Z.N. and Shahin, M.M.: "Interferometric determination of optical anisotropy in fibres, 3. multi-layer fibres". J. Appl. Phys. 70, 4480 (1991).

67. Hamza, A.A., Fouda, I.M., Kabeel, M.A. and Shabana, H.M. : "Opto-mechanical properties of fibres, 3. optical properties of nylon 66 fibres as a function of the draw ratio". Polymer Testing, 10, 305 (1991).

68. Hamza, A.A., Fouda, I.M., Sokkar, T.Z.N., Shahin, M.M. and E.A. Seisa: "Opto-mechanical properties of fibres, 4. optical anisotropy in "Terylene" polyester fibres". Polymer Testing 11, 233 (1992).

69. Hamza, A.A., Fouda,I.M., Sokkar,T.Z.N., Shahin,M.M. and Seisa, E.A. : "Opto-mechanical properties of fibres, 5. Refractive index profile of stretched "Terylene" polyester fibres". Polymer Testing, 11, 297 (1992).

70. Hamza, A.A., Ghander, A.M. and Mabrouk. M.A. : "Some parameters affecting the determination of the refractive index profile of optical fibres by Interferometry". Pure and Appl. Opt., 1, 71 (1992).

71. Hamza, A.A.: "Microinterferometric studies on fibrous materials". Proceedings of the International Conference "Interferometry 89", SPIE, vol.1121, P. 340 (1990).

72. Sokkar, T.Z.N., Kabeel, M.A., Ramadan, W.A. and Hamza, A.A. : "A contribution to the study of color of fabrics". Color Research and Application, 17, 219 (1992).

73. Hamza, A.A., Sokkar, T.Z.N., and Ramadan, W.A. : "On the micro-interferometric determination of refractive indices and birefringence of fibres". Pure and Appl. Opt.1, 321 (1992).

74. Hamza, A.A., Fouda, I.M., Sokkar, T.Z.N., Shahin, M.M. and Seisa, E.A.: "Interferometric studies on polymer fibres, 1. application of mutiple-beam Fizeau method for the characterization of homogeneous polymer fibres". Polymers & Polymer Composites, 1, 367 (1993).

75. Hamza, A.A., Amer, M.A., Abd El-Kader, H.I. and Nasr, A.M. : "Optical properties of cuprammonium fibres". Polymer Testing, 12, 243 (1993).

76. Hamza, A.A., Amer, M.A., Abd El-Kader, H.I. and Nasr, A.M.: "Interferometric studies on fibres with irregular transverse sections". Polymer Testing, 12, 299 (1993).

77. Hamza, A.A., Ghander, A.M., Sokkar, T.Z.N., Mabrouk, M.A. and. Ramadan, W.A. : "On the determination of the refractive index of a fibres: 1. Skin-core fibre". Pure and Appl. Opt. 3, 943 (1994).

78. Hamza, A.A., Fouda, I.M., Sokkar, T.Z.N., Shahin, M.M. and Seisa, E.A. : "Interferometric studies on polymer fibres II. Application of multiple-beam Fizeau method for the characterization of multilayer fibres". Polymers & Polymer Composites, vol.2, No.5, 299 (1994).

79. Hamza, A.A., Fouda, I.M., El-Tonsy, M.M. and El-Sharkawy, F.M. : "Opto-thermal properties of fibres. I. Relations between optical properties and change of the density and mechanical loss factor for annealed polyester fibres". Journal of Applied Polymer Science, vol.56, 1355 (1995).

80. Hamza, A.A., Sokkar, T.Z.N., Ghander, A.M., Mabrouk, M.A. and Ramadan, W.A. : "On the determination of the refractive index of a fibre : II. Graded index fibre". Pure and Appl. Opt. 4, 161 (1995).

81. Hamza, A.A., El-Tonsy, M.M., Fouda, I.M. and El-Said, A.M. : "Colorimetric evaluation of thermooxidative degradation of nylon 6 fibres". Journal of Applied Polymer Science, 57, 265 (1995).

82. Hamza, A.A., Fouda, I.M., Kabeel, M.A. and Shabana, H.M. : "Opto-mechanical properties of fibres, 6 : structural characteristics and optical properties of PE fibres". Polymer Testing, 15, 35 (1996).

83. Hamza, A.A., Fouda, I.M., Sokkar, T.Z.N., Shahin, M.M. and Seisa. E.A. : "Opto-thermal properties of fibres : part 1. optical behavior of annealed polypropylene fibres as a function of the draw ratio". Journal of Materials Science, 30, 25 (1995).

84. Hamza, A.A., Fouda, I.M., El-Tonsy, M.M. and El-Sharkawy, F.M.: “Opto-thermal properties of fibers. II. Annealing effect on the Birefringence variations of polyester fibers”. Journal of Applied Polymer Science, 60, 1239 (1996).

85. Hamza, A.A., Fouda, I.M., Sokkar, T.Z.N., and El-Bakary, M.A. : "Opto-thermal properties of fibres : 3. Effect of the anisotropic optical parameters in polypropylene fibres as a function of annealing process". Polymer Testing, 15, 245 (1996).

86. Hamza, A.A., Fouda, I.M., Sokkar, T.Z.N. and El-Bakary, M.A.: "Effect of annealing on the optical and mechanical properties of cold drawn polypropylene fibres". Polymer International, 39, 129 (1996).

87. Hamza, A.A., Fouda, I.M., El-Tonsy, M.M. and El-Sharkawy, F.M.: "Opto-thermal properties of fibers. VI. Effect of annealing on some of the optical and dynamic mechanical parameters of polyester fibers", Journal of Applied Polymer Science, 59, 1585 (1996).

88. Hamza, A.A., Fouda, I.M., Kabeel, M.A. and Shabana, H.M.: “Opto-Mechanical properties of fibres. 7: Relation between cold drawing behaviour of Nylon 6 fibres from an Egyptian manufacturer and their optical properties” , Polymer Testing, 15, 301 (1996).

89. Hamza, A.A., Fouda, I.M., Sokkar, T.Z.N. and El-Bakary, M.A.: “Opto-thermal properties of fibers. V. optical anisotropy in silk fibers as a function of annealing process”, J. Applied Polymer Science, 60, 1289 (1996).

90. Hamza, A.A., Fouda, I.M., Kabeel, M.A., Seisa, E.A. and El-Sharkawy, F.M. : “Opto-thermal properties of fibers 2-structural characteristics of cold drawn annealed Egyptian polymer (PET) fibers”, Polymer Testing, 16, 303 (1997).

91. Hamza, A.A., Fouda, I.M., Kabeel, M.A., Seisa, E.A., and El- Sharkawy, F.M. : “Optothermal properties of fibres. VIII structure orientation study of annealed Egyptian polyester fiber”, J. Applied Polymer Science, 65, 2031 (1997).

92. Hamza, A.A., Fouda, I.M., Kabeel, M.A., Seisa, E.A. and El- Sharkawy, F.M. : “1-Opto-thermal properties of fibres annealing effect on the birefringence variations of polyester fibres”, Journal of Polymer Science, Part B, Polymer Physics, 36, 555 (1998).

93. Hamza, A.A., Fouda, I.M., Kabeel, M.A., Seisa, E.A. and El- Sharkawy, F.M. : “Opto-thermal properties of fibres. XI. The effect of thermal annealing of drawing behavior for Egyptian polyester fibres on the crystallinity and some optical parameters”, J. Applied Polymer Science , 68, 1371 (1998).

94. Hamza, A.A., Fouda, I.M., Sokkar, T.Z.N. and El-Bakary, M.A. : “Optothermal properties of fibres. IX. Study changes of optical parameters by multiple-beam technique due to thermal annealing for natural silk fibres”, J. Applied Polymer Science , 69, 1495 (1998).

95. Hamza, A.A., Fouda, I.M., Kabeel, M.A., El-Shrif, M. and El- Sharkawy, F.M. : “Opto-thermal properties of fibres: Evaluation of colour parameters of annealed nylon 6,6 fibres”, Polymers & Polymer Composites, 7, 53 (1998).

96. Hamza, A.A. and Nasr, A.M : “Interferometric studies on multi-mode step-index optical fibres”, Pure and Appl. Opt., 7, 449 (1998).

97. Hamza, A.A., Sokkar, T.Z.N., El-Farahaty, K.A. and El-Dessouky, H.M. : “Comparative study on interferometric techniques for measurement of the optical properties of a fibre”, J. Opt. A: Pure and Appl. Opt., 1, 41 (1999).

98. Hamza, A.A., Fouda, I.M., Sokkar, T.Z.N. and El-Bakary, F.M. : “Determintation of spectral dispersion curves of polypropylene fibres”, J. Opt. A. Pure and Appl. Opt., 1, 359 (1999).

99. Hamza, A.A., Fouda, I.M., Kabeel, M.A., and El- Sharkawy, F.M. : “Opto-thermal properties of fibres: 5-Structure variations in nylon 66 fibres due to different thermal conditions”, Polymer Testing, 18 , 155-180 (1999).

100. Hamza, A.A., Sokkar, T.Z.N., El-Farahaty, K.A. and El-Dessouky, H.M.: “Influence of temperature on the optical and structural properties along the diameter of : I. Polymer fibres”, J. of Phys.: Condensed Matter 11, 5331-5341(1999).

101. Hamza, A.A., Sokkar, T.Z.N., Mabrouk, M.A. and El-Morsy : “Refractive index profile of polyethylene fibre using interactive multiple-beam Fizeau Fringe analysis”, J. Applied Polymer Science 77, 3099-3106 (2000).

102. Hamza A.A.”The present state of development of interferometry of fibrous materials”, Vlàkna a Texil 7 (2) 65-74 (2000).

103. Hamza A.A., Sokkar, T.Z.N., and El-Bakary, M.A., ”Determining the optical properties of highly oriented fibres using a muliple-beam technique”, J. Opt. A: Pure Appl. Opt., 3, 421 (2001).

104. Hamza A.A., Fouda I.M., Sokkar, T.Z.N. and El-Bakary M.A.”The spectral dispersion curves of highly oriented fibres”, Polymer Testing, 20, 847 (2001).

105. Hamza A.A. and Mabrouk M.A.”The use of interferometric techniques in fibres analysis and research”, The sixth international conference on “Theoretical and experimental problems of materials Engineering”, Held in University of Trencin, Solvak Republic, Sep. (2001).

106. Hamza A.A., Mabrouk M.A., Ramadan W.A. and Shams-Eldin M.A. ”Determination of GR-IN optical fibre parameters from transverse interferograms considering the refraction of the incident ray by the fibre”, Opt. Comm., 200, 131 (2001).

107. El-Morsy M.A., Yatagai T., Hamza A.A., Mabrouk M.A. and Sokkar T.Z.N. ”Automatic refractive index profiling of fibres by phase analysis method using Fourier transform”, Optics & Laser in Engineering 38 , 509 ( 2002 ).

108. Hamza A.A., Fouda I.M., Sokkar, T.Z.N., Sadek A.M. and El-Bakary M.A. ”Spectral dispersion curves of polymeric birefringent textile fibres”, Journal of Applied Polymer Science, 84, 2481 (2002).

109. Belal, A.E., Hamza A.A., Sokkar, T.Z.N., El-Farahaty, K.A. and Yassien, K.M.. ”Opto-thermal behavior of polypropylene fibres using a modified hot-stage attached to the interference microscope”, Polymer Testing, 21, 877 (2002).

110. Hamza A.A., Sokkar, T.Z.N., El-Bakary M.A. and Ali, A.M.”Variable wavelength microinterferometry applied for irregular fibres”, J. Opt. A: Pure Appl. Opt., 4, 371 (2002).

111. El-Morsy, M.A. Yatagai, t., Hamza, A.A., Mabrouk, M.A. and Sokkar, T.Z.N. “Multiple-beam Fizeau fringe-pattern analysis using Fourier transform method for accurate measurement of fiber refractive index profile of polymer fibre”, Journal of Applied Polymer Science, 85, 475 (2002).

112. Hamza, A.A., Sokkar, T.Z.N., El-Bakary, M.A. and Ali, A.M. “Interferometric determination of regular and/or irregular transverse sectional shape of homogeneous fibres“ Meas. Sci. Technol., 13, 1931 (2002).

113. Hamza, A.A., Sokkar, T.Z.N., El-Bakary, M.A. and Ali, A.M. “An interferometric method for studying the influence of temperature on the mean refractive indices and cross-sectional area of irregular fibres”, Polymer Testing, 22, 83 (2003).

114. Hamza, A.A., Fouda, I.M.,Sokkar, T.Z.N., El-Farahaty, K.A,.  El- Dessouky, H.M.  and Helaly, S.A.  “Opto-mechanical devices attached with the interference microscopes designed for fibre characterization” ArchTex  Conference, Lodz, Poland, 19-20 March-91, (2003).

115. Hamza, A.A., Mabrouk, M. A.  Ramadan, W. A . and Emara, A. M. “Refractive index and thickness determination of thin-films using Lloyd's interferometer” Optics Communication.225, 341(2003).

116. Hamza, A.A.,  Sokkar, T.Z.N. El-Farahaty, K.A. and El-Dessouky, H.M.“Determination of the intrinsic birefringence of polymeric fibres” Polym.  Testing, 23, 203 (2004).

117. Hamza, A.A., Sokkar, T.Z.N. El-Farahaty, K.A.  and El-Dessouky, H.M.   “Influence of temperature on the optical and structural properties along the diameter of optical fibres” Opt. Laser & Eng. 41, 2, 261 (2004).

118. Hamza, A.A., Sokkar, T.Z.N.and El-Bakary, M.A. “determination of the variation of optical and geometrical parameters of fibres due to the cold drawing process “ Meas. Sci. Technol., 15, 831 (2004).

119. Shams-el-Din, M. A., Wochnowski, C., Metev, S., Hamza, A.A. and Jüptner,W. , "Determination of the refractive index depth profile of an UV-laser generated waveguide in aplanner polymer chip" Applied Surface Science 236, 31 (2004).

120. Hamza, A.A., Mabrouk, M. A., Ramadan, W. A. and Wahba, H. H., ''Corindex determination of a thick fiber using lens-fibre  interference (LFI) technique"" Optics and Lasers in Engineering, 42, 121 (2004).

121. Hamza, A.A., Sokkar, T.Z.N., El-Farahaty, K.A. , El-Morsy, M. A. and El-Dessouky, H.M. , "Detecting and Avoiding the Necking Deformation Along Polypropylene Fibre Axis Using the Fringe Pattern Analysis of Multiple-Beam Microinterferometry" Optics & Laser Technology 37, 532, (2005).

122. Hamza, A.A., Sokkar, T.Z.N. and El-Bakary, M.A., “Interferometric Determination of the Refractive Indices and Birefringence of Some Highly Oriented Fibres” Optics & Laser Technology 38,162 (2006).

123. A.A.Hamza, T.Z.N.Sokkar, K.A. El-Farahaty and H.M. El-Dessouky, “Optothermomechanical Device Designed for Fibres characterization Interferometrically ” J. Appl. Polym. Sci. 95, 647 (2005).

124. Shams-Eldin M. A., Wochnowski C., Koerdt M., Metev S., Hamza A. A., Juptner W., "Characterization of the optical-functional properties of a waveguide written by an UV-Laser into a Planar Polymer Chip" Optical Materials, 27, 1138, (2005).

125. Hamza A.A., Belal, A.E., Sokkar, T.Z.N., El-Bakary, M.A and Yassien, K.M. " Determination of the spectral dispersion curves of highly oriented fibres using multiple-beam microinterferometry" , "J. of Polymeric Materials, 55, 605 (2006)

126. Belal, A.E., Hamza A.A., Sokkar, T.Z.N., El-Bakary, M.A. and Yassien, K.M. " Effect of  temperature on the dispersion properties of polypropylene fibres" J. Appl. Polym Sci. 98 ,1135 (2005).

127. Hamza A.A., Sokkar, T.Z.N., El-Bakary, M.A. " Interferometric determination of refractive indices and birefringence of some highly oriented fibres" Optics&Laser Technology 38, 162, (2006).

128. Wochnowski, C., Shams – Eldin, M.A., Metev, S., Hamza A. A. and Juptner, W. "Mode Field distribution of an integrared – optical waveguide generated by UV- Laser radiation at the surface of a planar polymer Chip." Optics Communications  262, 57, (2006).

129. Hamza, A.A. , Belal, A.E., Sokkar, T.Z.N, El – Dessouky H.M. and Yassien, K.M. " Detection of necking deformation along polypropylene fibres axis at low draw ratios using multiple – beam microinterferometry" Optics and Laser Technology ,39,681 (2007)  .

130. Hamza, A. A., Belal, A.E., Sokkar, T.Z.N., El-Dessouky, H.M. and Agour, M.A. "Interferometric studies on the influence of temperature on optical and dispersion parameters of GRIN optical fibre". Optics and Laser in Engineering 45, 145 (2007).

131. Hamza, A.A., Belal, A.E., Sokkar, T.Z.N., El-Bakary and M.A., Yassien, K.M. "Measurement  of the spectral dispersion curves of low birefringence    polymer fibres" Optics and Lasers in Engineering 45, 922 (2007).

132. Hamza ,A.A., Belal, A.E., Sokkar, T.Z.N., El-Bakary and  M.A., Yassien, K.M." Interferometric detection of structure deformation due to cold drawing of polypropylene fibres at high draw ratios" J. Opt. A: Pure Appl. Opt. 9, 820 (2007).

133. El-Dessouky, H.M., Hamza, A.A., Belal, A.E., Sokkar, T.Z.N., and Yassien, K.M "Interferometric studies for the annealing effects on the necking  deformation along polypropylene fibres" Journal of Engineered fibre and fabrics. 2, 1 (2007).

134. Hamza, A.A., Sokkar, T.Z.N., El-Bakary, M.A., Ali, A.M. and El-Morsy, M.A. "Determination of the geometrical and optical properties of irregular fibres as a function of the draw ratio". International Journal of Polymeric materials. 57, 343 (2008).

135. Hamza, A.A., Sokkar, T.Z.N., El-Morsy, M.A., and Nawareg, M.A.E "Automatic determenation of refractive index profile, sectional area, and shape of fibers having regular and/or irregular transverse sections "Optics and Laser Technology. 40 ,1082 (2008).

136. Hamza, A.A., Sokkar, T.Z.N., El-Bakary M. A., El-Morsy, M.A. , Ali, A. M. “Determining the optical and geometrical properties of irregular fibers during the dynamic cold drawing process” journal of Applied Polymer Science, vol. 112, 1909-1915 (2009).

137. 137. Hamza, A.A., Sokkar, T.Z.N., El-Morsy, M.A. & Nawareg, M.A.E, “Automatic determination of refractive index profile of fibres having regular and/or irregular transverse sections considering the refraction of light rays by the fibre”, Optics Communications, vol. 282, 27-35 (2009).

138. 138. El-Dessouky, H.M., Mahmoudi, M. R., Lawrence, C. A., Yassien, K. M., Sokkar, T.Z.N., Hamza, A.A. “On the physical behaviour of isotactic polypropylene fibers extruded at different draw-down ratios, I- optical properties and cold-drawing”. Polymer Engineering and Science 49, 2116-2124 (2009).

139. Hamza A.A., Sokkar T.Z.N, El-Morsy M.A, Raslan M.I., Ali A.M.“3D refractive index profile for the characterization of necking phenomenonalong stretched polypropylene fibres”Optics Communications, 283, 1684 (2010).

140. Hamza A.A., Sokkar T.Z.N.,EL-Bakary M.A., Ali A.M. “On line interferometric investigation of the neck propagation phenomena of stretched  olypropylene fibre” Optics & Laser Technology, 42, 703 (2010).

141. Hamza A. A., Sokkar T. Z. N., El-Bakary M. A. and Yassien K. M. “An interferometric detection of micro-cracks deformation for highly drawn polypropylene fibres” Fibers and Polymer 11,738 (2010).

142. Hamza A.A., Sokkar T.Z.N., El-Farahaty K.A., Raslan M.I., “Reconstruction of refractive indices distribution in 3D using a single  pattern of multiple-beam interference fringes for online investigation of necking phenomenon”, Polymer Testing, 29,1031 (2010).

143. Hamza A. A., Sokkar T. Z. N., El-Farahaty K.A., Raslan M.I., On-line opto-viscoelastic analysis of polypropylene fibres using  multiple-beam Fizeau fringes in transmission and a modified creep device” Polym Int.59,1021 (2010).

144. A. A. Hamza, T. Z. N. Sokkar, and M. A. El-Bakary, Interferometric Determination of the Birefringence of Thermo-Tropic Polyester Fibers and Its Copolymers of Structure (PCPT-co-CPO) Journal of Applied Polymer Science, Vol. 125, 1814-1821 (2012).

145. Hamza A. A., Sokkar T. Z. N., El-Farahaty K. A., Raslan M. I., A novel double-image Fizeau system for accurate investigation of anisotropic polymer fibres, Journal of microscopy, 254,84-94 (2014).

146. Hamza A. A., Sokkar T. Z. N., El-Farahaty K. A., Raslan M. I., A novel simultaneous photoelastic and two beam interferometric system: I. Dynamic full‐field evaluation of the elasticity modulus profile of polymeric fibres, Journal of microscopy, 254, 137-145 (2014).

147. Ramadan W. A., Shams El-Din M. A., Wahba H. H., El-Tawargy A. S., Hamza A. A., Lens–fibre interference proposed to monitor a transparent sheet’s thickness variations, Applied Physics B, 117, 1073-1080 (2014).

148. Sokkar T. Z. N., El-Farahaty K. A., Ramadan W. A., Wahba H. H., Raslan M. I., Hamza A. A., Nonray tracing determination of the 3D refractive index profile of polymeric fibres using single‐frame computed tomography and digital holographic interferometric technique, Journal of microscopy, 257, 208-216 (2014).

149. Hamza A. A., Sokkar T. Z. N., El-Farahaty K. A., Raslan M. I., A proposed method to reconstruct the three dimensional dispersion profile of polymeric fibres based on variable wavelength interferometry, Journal of microscopy, 257, 123-132 (2015).

150. Sokkar, T. Z. N., El-Farahaty K. A., Ramadan W. A., Wahba H. H., Raslan M. I., Hamza A. A., A novel method for identifying the order of interference using phase-shifting digital holography, Journal of Microscopy, 262, 73-84 (2015).

151. Sokkar T. Z. N., El-Farahaty K. A., Raslan M. I., Hamza A. A., Experimental investigation of craze morphology of isotactic polypropylene using computed tomography, Journal of microscopy, 263, 97-105 (2016).

152. Sokkar T. Z. N., El-Farahaty K. A., El-Bakary M. A., Omar E. Z., Hamza A. A.,  A modified method for accurate correlation between the craze density and the optomechanical properties of fibers using Pluta microscope, Microscopy research and technique, 79, 422-430 (2016).

153. Sokkar T. Z. N., El-Farahaty K. A., El-Bakary M. A., Omar E. Z., Agour M., Hamza A. A.,  Adaptive spatial carrier frequency method for fast monitoring optical properties of fibres, Applied Physics B: Lasers and Optics, 122, 1-14 (2016).

154. Sokkar T.Z.N,  EL- Farahaty K.A., Ramadan W.A., Wahba H.H., Raslan M.I. , Hamza A.A., "A novel method of identifying the order of interference using phase-shifting digital holography", journal of microscopy, Vol. 262, Issue 1 2016, pp.73-84.

155. Sokakar T.Z.N, El Farahaty K.A.,El Bakary M.A., Omer E. and Hamza A.A., “Characterization of axially tilted fibres utilizing a single-shot interference pattern" Optics and Lasers in Engineering,

     91, 144-150 (2017).

156. Sokkar T.Z.N., El Farahaty K.A., El Bakary M.A., Omer E. and Hamza A.A., “Optical birefringence and molecular orientation of crazed fibres utilizing the phase shifting interferometric technique" Optics and Laser Technology,  94, 208-216 (2017).

157. Sokkar T.Z.N., El‐Farahaty K.A., Raslan M.I., El‐Khateep S.M., Hamza A.A., “The effect of relaxation on the deformation of iPP fiber due to creep process” Advances in Polymer Technology, (2017).

158. Sokkar T.Z.N., El Farahaty K.A., El Bakary M.A., Raslan M.I., Omer E., Hamza A.A., “Non-interferometric determination of optical anisotropy in highly-oriented fibres using transport intensity equation technique” Optics and Lasers in Engineering, 102, 10-16 (2018).

159. Sokkar, T.Z.N., El-Farahaty. K.A, Raslan, M.I., El-Khateep, S.M., Hamza, A.A., "The effect of relaxation on the deformation of iPP fiber due to creep process" Advances in Polymer Technology, 37(6), 2204-2214 (2018)

160. 160.  Sokkar T.Z.N, El Bakary M.A, Sewidan M.A., Hamza A A “The Influence of Grafting Process on the Optical, Geometrical and Structural Properties of Nylon-6 Fibers” Microscopy Research & Technique, 83, 56-65 (2020).

161. Hamza A.A. and Raslan M.I, “ Dual-image Multiple–Beam Fringes of Equal Chromatic Order for Dynamic Characterization of Fibres” Journal of Optical Society of America B, 37, 393-399, (2020).

162. Omar E.Z, Sokkar T.Z.N, Hamza A.A, “In Situ Investigation and Detection of Opto-mechanical Properties of Polymeric Fibres from their Digital Distorted Microinterferograms using Machine Learning Algorithms”, Optics and Laser Technology, 129 (2020) 106295.

163. A.A. Hamza,T.Z.N.Sokkar, M.A.El-Bakary and M. A. Swidan, “Opto- mechanical Investigating the Impact of Grafting Polyamide-6 Fibres with PMMA on its Intrinsic Optical Properties " Polym. Eng. Sci., 1930-1939, 60(8), (2020).

164. A.A. Hamza,T.Z.N.Sokkar, M.A.El-Bakary and A. A. S. Azam, “A Quantitative study on using digital photoelasticity for characterising the effect of stretching speed on the necking phenomenon., J. Polym. Eng., 753–762, 40(9) (2020).

165. T.Z.N.Sokkar, M.A.El-Bakary, A. A. S. Azam and A.A. Hamza, “Fractographic characterisation of isotactic Polypropylene fibres" Microscopy Research and Technique. 1022–1035, 84, (2021). DOI: 10.1002/jemt.23663

166. El-Sayed, N.M., El-Bakary, M.A., Ibrahim, M.A., Elgamal, M.A., and A.A. Hamza, " Characterization of the mechanical and structural properties of PGA/TMC copolymer for cardiac tissue engineering" Microscopy Research and Technique, 1596-1606, 84, (2021).

167. Sokkar, T.Z.N., El-Bakary, M.A., Azam, A.A.S., and Hamza, A.A., “Photoelastic characterization of shear-bands in mechanically stretched polymeric fibers” Microscopy Research and Technique, (2021). Article in Press

168. Sokkar, T.Z.N., El-Bakary, M.A., Sewidan, M.A., and Hamza, A.A. “FECO fringes for investigating the effect of grafting process on the dispersion properties of polyamaide-6 fibers” Microscopy Research and Technique, (2021). Article in Press

169. T.Z.N.Sokkar, M.A.El-Bakary, A. A. S. Azam and A.A. Hamza, Opto-Thermo-Mechanical Characterization of Crazing Phenomena Observed for Isotactic Polypropylene Fibers Using Digital Photoelasticity and the Computed Tomography Techniques., Journal of Macromolecular Science, Part B: Physics, 2021. Article in Press.

170. M.I.Raslan, T.Z.N.Sokkar, and A.A. Hamza, An algorithm for direct birefringence measurements using intensities of digital photoelastic patterns of fibres., Applied Physics B: Lasers and Optics, 5, 128(1), (2022).

171. T.Z.N.Sokkar, M.A.El-Bakary, M.I.Raslan, M.A.Sewidan and A.A. Hamza, “A hybrid method of phase shifting interferometry and optical tomographic techniques for determining the optical anisotropy of grafted nylon-6 fibres with PMMA polymer., Optik, 251, 168485 (2022).

172. A.A. Hamza, M.A. El-Bakary, M.A. Ibrahim, M.A. Elgamal, N.M. El-Sayed, Investigate the degradable behavior of a poly (glycolide-co-trimethylene carbonate) suture material used in a vascular surgery. Polymer Bulletin, 1-19, (2022).