Abstract: Although skin cancers are prevalent worldwide, it is uncommon in Ha’il region in the Kingdom of Saudi Arabia, mostly non-melanoma sub-type. During a 4-year period from 2014 to 2017, out of a total of 120 cases of skin lesions, 29 non-melanoma cancers were retrieved from histopathology files obtained from King Khalid Hospital. As part of the study, all cases of skin cancer diagnosed during 2014 -2017 have been revised and the clinicopathological data recorded. The results show that Basal cell carcinoma (BCC) was the most common neoplasm (36%), followed by cutaneous lymphomas (mostly mycosis fungoides 25%), squamous cell carcinoma (SCC) (21%) and dermatofibrosarcoma protuberans (DFSP) (11%). Only one case of metastatic carcinoma was recorded. BCC nodular type was the most prevalent, with a mean age 57.6 years and mean size 2.73 cm. SCC was mostly grade 2, with mean size 1.9 cm and an older mean age of 72.3 cm. Increased size of lesion positively correlated with older age (p = 0.001). Non-melanoma skin cancer in Ha’il region is not frequently encountered. BCC is the most frequent followed by cutaneous T-cell lymphomas and SCC. The findings in this study were in accordance with other parts of, but much lower than other parts of the world.
Abstract: Bio-batteries represent an entirely new long-term, reasonable, reachable, and eco-friendly approach to generation of sustainable energy. In the present experimental work, we have studied the effect of the generation of power by bio-battery using different electrode pairs. The tests show that it is possible to generate electricity using cow’s urine as an electrolyte. C-Mg electrode pair shows maximum Voltage and Short Circuit Current (SCC), while C-Zn electrode pair shows less Open Circuit Voltage (OCV) and SCC. By the studies of cow urine and different electrodes, it is found that C-Zn electrode battery is more economical. The cow urine battery with C-Zn electrode provides maximum power (707.4 mW) and durability (up to 145 h). This result shows that the bio-batteries have the potency to full fill the need of electricity demand for lower energy equipment.
Abstract: Bio-batteries represent an entirely new long-term, reasonable, reachable and ecofriendly approach to produce sustainable energy. In the present experimental work, we have studied the effect of generation of power by bio-battery using different electrode pairs. The tests show that it is possible to generate electricity using cow dung as an electrolyte. C-Mg electrode pair shows maximum voltage and SCC (Short Circuit Current) while C-Zn electrode pair shows less OCV (Open Circuit Voltage) and SCC. We have chosen C-Zn electrodes because Mg electrodes are not economical. By the studies of different electrodes and cow dung, it is found that C-Zn electrode battery is more suitable. This result shows that the bio-batteries have the potency to full fill the need of electricity demand for lower energy equipment.
Abstract: Due to the difficult placement and vibration between reinforcements of reinforced concrete and the defects that it may cause, the use of self-compacting concrete (SCC) is becoming more widespread. Ordinary Portland Cement (OPC) is the most widely used binder in the construction industry. However, the manufacture of this cement results in a significant amount of CO2 being released, which is detrimental to the environment. Thus, an alternative to reduce the cost of SCC is the use of more economical and environmental mineral additives in partial or total substitution of Portland cement. Our study is in this context and aims to develop SCCs both economic and ecological. Two natural pozzolans such as pumice and zeolite are chosen in this research. This research tries to answer questions including the microstructure of the two types of natural pozzolan and their influence on the mechanical properties as well as on the transport property of SCC. Based on the findings of this study, the studied zeolite is a clinoptilolite that presents higher pozzolan activity compared to pumice. However, the use of zeolite decreases the compressive strength of SCC composites. On the contrary, the compressive strength in SCC containing of pumice increases at both early and long term ages with a remarkable increase at long term. A correlation is obtained between the compressive strength with permeable pore and capillary absorption. Also, the results concerning compressive strength and transport property are well justified by evaporable and non-evaporable water content measurement. This paper shows that the substitution of Portland cement by 15% of pumice or 10% of zeolite in HSSCC is suitable in all aspects.
Abstract: Current trends in the building industry are oriented towards the reduction of maintenance costs and the ecological benefits of buildings or building materials. Surface treatment of building materials with photocatalytic active titanium dioxide added into concrete can offer a good solution in this context. Architectural concrete has one disadvantage – dust and fouling keep settling on its surface, diminishing its aesthetic value and increasing maintenance e costs. Concrete surface – silicate material with open porosity – fulfils the conditions of effective photocatalysis, in particular, the self-cleaning properties of surfaces. This modern material is advantageous in particular for direct finishing and architectural concrete applications. If photoactive titanium dioxide is part of the top layers of road concrete on busy roads and the facades of the buildings surrounding these roads, exhaust fumes can be degraded with the aid of sunshine; hence, environmental load will decrease. It is clear that options for removing pollutants like nitrogen oxides (NOx) must be found. Not only do these gases present a health risk, they also cause the degradation of the surfaces of concrete structures. The photocatalytic properties of titanium dioxide can in the long term contribute to the enhanced appearance of surface layers and eliminate harmful pollutants dispersed in the air, and facilitate the conversion of pollutants into less toxic forms (e.g., NOx to HNO3). This paper describes verification of the photocatalytic properties of titanium dioxide and presents the results of mechanical and physical tests on samples of architectural lightweight self-compacting concretes (LWSCC). The very essence of the use of LWSCC is their rheological ability to seep into otherwise extremely hard accessible or inaccessible construction areas, or sections thereof where concrete compacting will be a problem, or where vibration is completely excluded. They are also able to create a solid monolithic element with a large variety of shapes; the concrete will at the same meet the requirements of both chemical aggression and the influences of the surrounding environment. Due to their viscosity, LWSCCs are able to imprint the formwork elements into their structure and thus create high quality lightweight architectural concretes.
Abstract: Implementing significant advantages in the supply of self-compacting concrete (SCC) is necessary because of the, negative features of SCC. Examples of these features are the ductility problem along with the very high cost of its constituted materials. Silica fume with steel fiber can fix this matter by improving the ductility and decreasing the total cost of SCC by varying the cement ingredients. Many different researchers have found that there have not been enough research carried out on the steel fiber-reinforced self-compacting concrete (SFRSCC) produced with silica fume. This paper inspects both the fresh and the mechanical properties of SFRSCC with silica fume, the fresh qualities where slump flow, slump T50 and V- funnel. While, the mechanical characteristics were the compressive strength, ultrasound pulse velocity (UPV) and elastic modulus of the concrete samples. The experimental results have proven that steel fiber can enhance the mechanical features. In addition, the silica fume within the entire hybrid mix may possibly adapt the fiber dispersion and strengthen deficits due to the fibers. It could also improve the strength plus the bond between the fiber and the matrix with a dense calcium silicate-hydrate gel in SFRSCC. The concluded result was predicted using linear mathematical models and was found to be in great agreement with the experimental results.
Abstract: A self-compacting concrete (SCC) is the one that can
be placed in the form and can go through obstructions by its own
weight and without the need of vibration. Since its first development
in Japan in 1988, SCC has gained wider acceptance in Japan, Europe
and USA due to its inherent distinct advantages. Although there are
visible signs of its gradual acceptance in the North Africa through its
limited use in construction, Libya has yet to explore the feasibility
and applicability of SCC in new construction. The contributing
factors to this reluctance appear to be lack of any supportive
evidence of its suitability with local aggregates and the harsh
environmental conditions. The primary aim of this study is to explore
the feasibility of using SCC made with local aggregates of Eastern
Province of Libya by examining its basic properties characteristics.
This research consists of: (i) Development of a suitable mix for SCC
such as the effect of water to cement ratio, limestone and silica fume
that would satisfy the requirements of the plastic state; (ii) Casting of
concrete samples and testing them for compressive strength and unit
weight. Local aggregates, cement, admixtures and industrial waste
materials were used in this research.
The significance of this research lies in its attempt to provide
some performance data of SCC made in the Eastern Province of
Libya so as to draw attention to the possible use of SCC.
Abstract: The purpose of this paper is to highlight the
importance of the concept of competitiveness in the supply chain and
to present a conceptual framework for Supply Chain Competitiveness
(SCC). The framework is based on supply chain activities, which are
inputs, necessary for SCC and the benefits which are the outputs of
SCC. A literature review is conducted on key supply chain
competitiveness issues, its determinants, its various dimensions
followed by exploration for SCC. Based on the insights gained, a
conceptual framework for SCC is presented based on activities for
SCC, SCC environment and outcomes of SCC. The information flow
in the conceptual framework is bi-directional at all levels and the
activities are interrelated in a global competitive environment. The
activities include the activities of suppliers, manufacturers and
distributors, giving more emphasis on manufacturers- activities.
Further, implications of various factors such as economic, politicolegal,
technical, socio-cultural, competition, demographic etc. are
also highlighted. The SCC framework is an attempt to cover the
relatively less explored area of supply chain competitiveness. It is
expected that this work will further motivate researchers,
academicians and practitioners to work in this area and offers
conceptual help in providing a directions for supply chain
competitiveness which leads to improvement in the supply chain and
supply chain performance.
Abstract: Nowadays, the performance required for concrete
structures is more complicated and diversified. Self-compacting
concrete is a fluid mixture suitable for placing in structures with
congested reinforcement without vibration. Self-compacting concrete
development must ensure a good balance between deformability and
stability. Also, compatibility is affected by the characteristics of
materials and the mix proportions; it becomes necessary to evolve a
procedure for mix design of SCC.
This paper presents an experimental procedure for the design of
self-compacting concrete mixes with different water-cement ratios
(w/c) and other constant ratios by local materials. The test results for
acceptance characteristics of self-compacting concrete such as slump
flow, V-funnel and L-Box are presented. Further, compressive
strength, tensile strength and modulus of elasticity of specimens were
also determined and results are included here
Abstract: Natural pozzolan (NP) is one of the potential
prehistoric alternative binders in the construction industry. It has
been investigated as cement replacement in ordinary concrete by
several researchers for many purposes. Various supplementary
cementitious materials (SCMs) such as fly ash, limestone dust and
silica fume are widely used in the production of SCC; however,
limited studies to address the effect of NP on the properties of SCC
are documented. The current research is composed of different SCC
paste and concrete mixtures containing different replacement levels
of local NP as an alternative SCM. The effect of volume of paste
containing different amounts of local NP related to W/B ratio and
cement content on SCC fresh properties was assessed. The variations
in the fresh properties of SCC paste and concrete represented by
slump flow (flowability) and the flow rate were determined and
discussed. The results indicated that the flow properties of SCC paste
and concrete mixtures, at their optimized superplasticizer dosages,
were affected by the binder content of local NP and the total volume
fraction of SCC paste.
Abstract: The objective of this work is to study the influence of the properties of the substrate on the retrofit (thin repair) of damaged concrete elements, with the SCC. Fluidity, principal characteristic of the SCC, would enable it to cover and adhere to the concrete to be repaired. Two aspects of repair are considered, the bond (Adhesion) and the tensile strength and the cracking. The investigation is experimental; It was conducted over test specimens made up of ordinary concrete prepared and hardened in advance (the material to be repaired) over which a self compacting concrete layer is cast. Three alternatives of SC concrete and one ordinary concrete (comparison) were tested. It appears that the self-compacting concrete constitutes a good material for repairing. It follows perfectly the surfaces- forms to be repaired and allows a perfect bond. Fracture tests made on specimens of self-compacting concrete show a brittle behaviour. However when a small percentage of fibres is added, the resistance to cracking is very much improve.