Safa Hamed | Cairo University (original) (raw)

Papers by Safa Hamed

Egyptian Journal of Chemistry, Mar 5, 2023

Archaeological studies always seek for understanding history and draw right pictures about the li... more Archaeological studies always seek for understanding history and draw right pictures about the life in the past in the different civilizations. Consequently, varieties of sciences are applied in these studies to extract the historical information. Hence this study investigated hair samples that were taken from four royal mummies with the aim of obtaining reliable information about the materials used in embalming, health status of these mummies, their age, and hair color that affects its composition. A variety of analytical techniques were applied in this study; digital microscope, polarizing optical microscope, environmental scanning electron microscope coupled with energy-dispersive X-ray unit, Fourier transform infrared spectroscopy, gas chromatography, and Raman spectroscopy analysis. The results showed the significance of hair in biomonitoring health status and determining age. Besides, it was proved that mastic resin has been used in embalming as early as the Second Intermediat...

The current study aims to elucidate and compare ultrastructure alterations that occurred in larch... more The current study aims to elucidate and compare ultrastructure alterations that occurred in larch wood (Larix decidua Mill.) and beech wood (Fagus sylvatica) which were artificially infested with the selected fungi; Aspergillus niger, Pencillium chrysogenum, Chaetomium globosum, (soft-rot fungi) Trichoderma viride and Alternaria alternata (surface mold). Environmental scanning electron microscope were utilized to examine the wood samples which were left three years. Microscopic examination showed differences in the patterns and mechanism of decay in the two wood species and cell types invaded by the selected fungi. A. nigar and P. chrysogenum can cause wood degradation more aggressively than C. globosum. Surface mold fungi, e.g. T. viride and A. alternata may cause alterations in wood ultrastructurally like soft-rot fungi. The results of this study encourage adding stain fungi and surface mold to wood destroying fungi classification, also recommending examination their enzymatic sys...

In the Police seizures museum, Citadel, Egypt, there are large numbers of the refundable objects,... more In the Police seizures museum, Citadel, Egypt, there are large numbers of the refundable objects, a lot of them undated. So, this study focuses on dating a fragment of a refundable wooden Egyptian coffin lid based on its technology and typology through multi-analytical techniques. The coffin lid was examined by visual investigation, optical microscope, Scanning electron microscope (SEM) and EDAX, FTIR spectroscopy and Xray diffraction. These investigations were carried on to identify the used wood, preparation layers, pigments and modern interventions. With the use of this information we tried to date this piece in accordance to the previous studies concerned with the coffin construction techniques through ages. The results showed that the stratigraphy of this coffin lid corresponds to the stratigraphy of the yellow coffins, which appeared at the 18th Dynasty (1575-1307 BC) and ending suddenly at the first half of twenty-two Dynasty (~945-840 BC), according to general similarities o...

Advanced Research in Conservation Science, 2021

• Investigating the status of storerooms in some Egyptian museums regarding pest management. • Se... more • Investigating the status of storerooms in some Egyptian museums regarding pest management. • Selection of the storerooms in suitable museums for the present study. • Placement and monitoring the sticky traps that were chosen and distributed inside some storerooms of the selected museums. • Identifying the collected insects and insect pests that were caught by traps. • Interpreting the results of catches' identification..

This study was conducted to diagnose and evaluate the deterioration of archaeological wood caused... more This study was conducted to diagnose and evaluate the deterioration of archaeological wood caused by bat excretions. The samples were collected from the ceiling of Mohamed Ali palace (1812), which is located in Suez, and Baron Empain palace (1911), which is located in Cairo, Egypt. The wooden samples were covered with a preparation layer (gesso) on one side. Parts from both sides of the wooden samples that suffered from the accumulation of bat excretions were examined. The effects of bat excretions on the anatomical structure and chemical composition of the wooden samples were examined and evaluated using various analytical methods, such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). In addition, a microbiological study was undertaken to identify microbial activity on the wood surface. The results showed that the wood suffered changes in its anatomical structure in addition to scratches on the wood surface that wer...

Advanced Research in Conservation Science, 2020

Investigating wood samples covered with preparation layers, similar in composition to ancient pai... more Investigating wood samples covered with preparation layers, similar in composition to ancient paint grounds • Assessment the penetration depth of preparation layers-inside native Ficus sycomorus (sycomore fig), Tamarix sp. (tamarisk wood) and Acacia sp. (acacia wood) after subjecting to natural and accelerated aging. • Determination of the factors on which penetration of the preparation layers within wood structure depend on. • Elemental analysis of the seven wooden samples of each of the three wood types was conducted.

Applied Sciences, 2020

In the present study, Acacia saligna (Labill.) H.L.Wendl. wood blocks with dimensions of 0.5 × 1 ... more In the present study, Acacia saligna (Labill.) H.L.Wendl. wood blocks with dimensions of 0.5 × 1 × 2 cm were inoculated with five molds (Aspergillus niger, A. flavus, Alternaria tenuissima, Fusarium culmorum, and Trichoderma harzianum) and the changes in the organic acids (oxalic, citric, tartaric, succinic, glutaric, acetic, propionic, and butyric) of powdered wood were analyzed by HPLC. The effects of the five inoculated fungi on the alterations to the wood cell wall ultrastructures were examined by TEM. The wood became more acidic as it was inoculated with the studied fungi. From the HPLC analysis, the oxalic acid (293.34 µg/g o.d.) in the A. saligna, A. tenuissima (167.33 µg/g o.d.), and T. harzianum (245.01 µg/g o.d.) wood decreased, but it increased in the A. flavus (362.08 µg/g o.d.), A. niger (1202.53 µg/g o.d.), and F. culmorum (431.85 µg/g o.d.) inoculated wood. Citric acid was observed in the wood inoculated with A. flavus (110 µg/g o.d) and A. niger (2499.63 µg/g o.d). T...

Drvna industrija, 2019

The present study investigates in-vitro the antifungal activity of two extracts (ethyl ether extr... more The present study investigates in-vitro the antifungal activity of two extracts (ethyl ether extracts of Schinus terebinthifolius ripened fruits and Pinus rigida heartwood) and two essential oils (Thymus vulgaris and Origanum majorana leaves) against two species of fungi; Trichoderma harzianum and Aspergillus niger. The results clearly show that O. majorana oil and P. rigida wood extract had the highest activity against both fungi and were chosen for the application on four wood species; Weeping-Wreath Wattle (Acacia saligna), Beech (Fagus sylvatica), Black Walnut (Juglans nigra) and Pitch Pine (Pinus rigida). Additionally, their impact on the wood structure was examined by FTIR, SEM and colorimetry. The study suggests that O. majorana oil appears to show the best results and could be used as friendly bio-fungicides to protect wood objects without changing their structures.

Egyptian Journal of Archaeological and Restoration Studies, 2019

Journal of Cultural Heritage, 2019

Pigment & Resin Technology, 2019

Purpose This paper aims to investigate the effect of acidity on the morphology of archeological p... more Purpose This paper aims to investigate the effect of acidity on the morphology of archeological paper, especially in the presence of colors and whether natural pigments play a role in the process of degradation. Design/methodology/approach The morphological changes in the cellulosic fibers of the manuscripts because of acidity were investigated using environmental scanning electron microscope (ESEM). Ten historical samples were collected from different manuscripts suffering from acidity. X-ray diffraction was used to identify the inks and pigments that were used in some samples. Additionally, Fourier transform infrared microscopy was used to identify the binding medium. Findings The results confirmed that carbon ink, ultramarine, cinnabar and gold pigments were applied to some manuscripts with Arabic gum. As for ESEM investigation, the results proved that acidity badly affected the integrity of the cellulosic fibers resulting in their embrittlement. The micrographs showed difference...

This paper focuses on the role of scanning electron microscope in understanding and assessing the... more This paper focuses on the role of scanning electron microscope in understanding and assessing the changes in the anatomical structure of archaeological wood caused by deterioration agents and treatment procedures. Scanning electron microscopy is considered an important tool for observing the structural changes in degraded wood tissues at the level of cell wall, evaluating their damage, and identifying the causal agent of decay patterns. Additionally it is very helpful in the assessment of materials and methods used in treatment of archaeological wood, especially during cleaning and consolidation processes which have different effects on the wood structure. Such valuable information helps in developing appropriate procedures for conserving wooden artifacts. Although the data obtained from SEM examination illustrates the morphological and structural changes of the wood, it sometimes provides an indication to the changes in its chemical composition. Therefore, investigations based on S...

This article reviews the application of nanotechnology in the conservation of archaeological wood... more This article reviews the application of nanotechnology in the conservation of archaeological wood based on their structure and deterioration. Nanotechnology can be applied in deacidification, cleaning, and consolidation of archaeological wood. Soft Nanoscience (microemulsions and micelles) can be used to remove contaminants and polymers, used in previous treatments, and to clean the wood surface. Hard Nanoscience (hydroxides nanoparticles in non-aqueous solvents) can be applied to deacidify wood of ancient shipwrecks, for example. The author highlight ways of treatments that were applied to other cultural heritage items and could be applied to archaeological wood but not examined yet, especially in the case of polychrome wood according to its structure.

International Biodeterioration & Biodegradation, 2013

ABSTRACT This paper focuses on the biodegradation of wood by two soft-rot fungi, Aspergillus nige... more ABSTRACT This paper focuses on the biodegradation of wood by two soft-rot fungi, Aspergillus niger and Penicillium chrysogenum, in soil which was artificially infested. The structural changes of pine and sycamore wood were evaluated by scanning electron microscope (SEM). Surprisingly, soft-rot fungi tolerate low moisture to cause extensive decay in the wood samples. The micrographs showed differences in hyphae colonization and wood degradation patterns between soft-rot species under this study; A. niger produced soft-rot decay type I (cavity formation) and soft-rot decay type II (erosion), while P. chrysogenum caused only soft-rot decay type II.

The investigation of Tutankhamuns' gilded wooden bed (Carter. No 377, GEM 14276) showed that ... more The investigation of Tutankhamuns' gilded wooden bed (Carter. No 377, GEM 14276) showed that the use of different organic materials during several restoration interventions since the discovery of the tomb included paraffin wax, mixture of rosin and paraffin wax and also mixture of rosin and bees wax [1, 2]. Unfortunately, their applications induced a drastic alteration of the interfacial properties of the object and lead to increased degradation as well as prevented the application of other materials for conservation [1, 3-5]. These previously added organic materials had to be removed, yet that had to be achieved without affecting the original gilding materials. The complete removal of these added materials is often a delicate problem, not only due to the lack of reversibility for resins or waxes, but also because of the poor cohesion of the gilded layer and its water sensitivity, as well as the thin thickness of gold leaves used in the bed. An important challenge for us is to f...

Journal of Archaeological Science: Reports, 2018

This paper describes for the first time in detail the investigation of a gilded wooden bed from k... more This paper describes for the first time in detail the investigation of a gilded wooden bed from king Tutankhamun's funerary collection since the discovery of the tomb in 1922; with the aim of identifying the botanical species of wood and the chemical composition of the materials used in the preparatory gilding layers and also the materials used in the previous treatments interventions. The botanical species of wood and textile were identified by observing the thin sections under an optical transmission light microscope; the gilding materials layered on the wood surface and the previous treatment materials were analyzed by several scientific and analytical measures including visible-induced ultraviolet luminescence (UVL), optical microscopy (OM), X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Cross-sections of gilding layers were also performed and studied by OM and environmental scanning electron microscopy (ESEM). The microscopic observation of wood thin sections made it possible to identify the wood used in the legs and angle brackets as Acacia sp, whereas Tamarix sp was used for the foot boards. Four preparation layers were observed on the wood surface via micro-stratigraphic analysis. An interesting black layer made of carbon (from vegetable and animal origin) was found between the wood surface and woven linen layer, the white preparation layer was identified as calcium carbonate and the coarse paste layer proved to be a mixture of calcite, quartz and hematite. The organic binder was composed of a protein-based material, most probably animal glue. Additionally, different materials were identified from previous treatments interventions. The analyses provided detailed information concerning the original materials and the materials added during the previous treatment interventions, which need to be considered when applying a future conservation plan.

This study was conducted to diagnose and evaluate the effect of commonly used cleaning methods in... more This study was conducted to diagnose and evaluate the effect of commonly used cleaning methods in Egypt on the anatomical structure of archaeological wood samples. Beech wood samples, which were taken from anonymous mashrabia, have been cleaned mechanically and chemically, then a scanning electron microscope (SEM) study was undertaken, to monitor any significant structural changes in wood samples due to cleaning processes. SEM data, however, show that cleaning procedures, both mechanical and chemical, affect the anatomical structure of wood, and don’t achieve the best result. The main problem is that the effect of reagents can’t be easily removed from wood structure. Ethyl alcohol proved to have the minimal effect on the wood structure in this study.