The Stability of Dextran Nitrate

The stability properties of dextran nitrates, prepared by nitric acid alone and by mixed acids, have been determined and their stabilisation has been also attempted. While the stability of the crude dextran nitrates varied appreciably according to the method of preparation, the stabilised forms possessed closely similar stability properties. The stability of the nitrated α-D-glucose polymeric carbohydrate dextran, as previously reported in the case of other α-D-glucose polymeric carbohydrate nitrates, is now apparently found much lower than that of the nitrated β-D-glucose polymeric carbohydrate cellulose.     

SUPPLY AND DEMAND OF LIGHT NAPHTHA AS POTENTIAL PETROCHEMICAL FEEDSTOCK IN SAUDI ARABIA

ABSTRACT

Saudi Arabia is a major crude oil producer and exporter. Additionally, with the completion of its master gas gathering and treatment system petrochemical industries became the Kingdom's second major industrial sector. Currently, the Saudi petrochemical industry depends mainly on (C₁) methane and (C₂) ethane components of associated gas (AG) and natural gas (NG) as feedstocks. A variety of basic petrochemicals are now being produced principally by plants of the Saudi Basic Industries Corporation (SABIC).

There is a necessity of enhancing the use of various under-utilized hydrocarbon resources. At present, one of the favored under-utilized resources and potential candidates for upgrading is light naphtha (LN). Because LN has the advantage of producing a more diverse petrochemical product portfolio than C₁ and C₂ components, it is expected that LN will assume an increasing importance as feedstock in the future development of petrochemical industries in Saudi Arabia. However, industrial opportunities for economies of large-scale production of petrochemicals based on LN might not be favored.

Saudi Arabia's chemical and petrochemical industrial sector has not yet been fully developed, and its production lines are not enough diversified to benefit from LN. The development and expansion of Saudi petrochemical industries usually follows the international trend in this sector, and benefits from its technological achievements. Worldwide global shift in the use of feedstock in this industrial sector will be reflected in the Saudi petrochemical industries. As the world trend is to maximize the utilization of under-utilized petroleum resources, one would expect optimization of LN utilization in Saudi Arabia in the near future.     

A novel augmented reality for hidden organs visualisation in surgery: enhanced super-pixel with sub sampling and variance adaptive algorithm

In recent years, Augmented Reality (AR) has gained more attention as an effective tool in medical surgeries. The potentials of using AR in the medical field can change conventional medical procedures. However, the technology still facing fundamental challenges, especially hidden organs, for example, the organs behind the bowel and liver. The surgeries in these areas lack accuracy in the visualization of the soft tissues behind the bowel and liver like the uterus and gall bladder. This research aims to improve the accuracy of visualisation and the processing time of the augmented video. The proposed system consists of an enhanced super-pixel algorithm with variance weight adaptation and subsampling method. The simulation studies show significant improvements in visualization accuracy and a reduction in processing time. The results show reduced visualisation error by 0.23 mm. It provides better accuracy of the video in terms of visualization error from 1.58?~?1.83 mm to 1.35?~?1.60 mm, and the processing time decreases from 50?~?58 ms/frames to 40?~?48 ms/frames. The proposed system \ focused on the pixel refinement for the 3d reconstruction of the soft tissue, which helps solve the issue of visualising the bowel and liver in an augmented video.

     

Predicted performance of magnetized semiconductor phase shifters for millimeter-wave microstrip array antennas

The tunable phase shift of a planar magnetized semiconductor phase shifter is presented, suitable for an integrated environment due to its miniature size, low-biasing requirements, and lower material related problems at millimeter-wave frequencies. A linear microstrip phased array antenna with an integrated semiconductor phase shifter is designed and the calculated beam steering properties are tabulated. The design process is verified by simulating similar ferrite-based linear phased array antennas.     

Electronic behaviour of iron ions at copper sites

The electronic properties of the ceramic superconductor Y-Ba-Cu-Fe-O system with different amounts of iron cations versus temperature are discussed. The spin fluctuations of copper and its relation to the superconducting state are discussed from the point of view of the mixed valence state of copper ions. The results suggested a spin-glass behaviour at low temperature.     

Note: Effect of some zinc chelates on the flammability and thermal behaviour of polypropylene

Some zinc chelates were prepared according to conventional methods, and were mixed with polypropylene in the presence and absence of a halogenated compound (Cereclor 70). The effect of these chelates on the flammability and thermal behaviour of polypropylene was studied by measuring the limiting oxygen index values and by the use of thermal analysis. This results showed that these chelates are ineffective in reducing the flammability of polypropylene but their effectiveness is enhanced to varying extents by the addition of Cereclor.     

Experimental study on the kinetics of water vapor sorption on selective water sorbents, silica gel and alumina under typical operating conditions of sorption heat pumps

A selective water sorbent (SWS) is a composite material consisting of a porous host matrix and a hygroscopic substance (commonly an inorganic salt) impregnated into its pores. This work presents an experimental investigation for the kinetics of water vapor sorption on two host materials; namely mesoporous silica gel and alumina in comparison with the two composites SWS-1L and SWS-1A formed by impregnating these two host matrices with CaCl₂. Moreover, the kinetics of water vapor sorption on microporous silica gel have been also investigated. The measurements have been carried out on 3 g samples of loose pellets on an isothermal wall under three different operating conditions of sorption heat pumps. The results obtained evidence a remarkable increase in the differential water loading of both SWS-sorbents over their host materials. However, and due to the increased diffusion resistance to water sorption resulting from the salt impregnation, the kinetics of water sorption into the host matrices is faster than that into the two SWS-composites. Moreover, SWS-1L is found to be faster than SWS-1A in sorbing water vapor. The differential water loading on microporous silica is about twice that on mesoporous silica and alumina, but the sorption kinetics are a little bit slower.     

Effect of supplementation with fish protein concentrate on protein and amino acid content of salt biscuit

Fish protein concentrate (FPC) from river Nile bolti fish (Tilapia nilotica) was prepared by two extractions with isopropyl alcohol. This FPC was used as a supplement to manufacture salt biscuit (mixed with cumin) for raising its nutritional quality. The supplementation at level of 4, 5, and 6% increased the protein content by about 2. 6, 3. 5, and 4.5% respectively. Increase was high in some amino acids such as glycine, serine, and threonine while cysteine, lysine, alanine, glutamic acid, arginine, isoleucine, and phenylalanine increased in a low rate. Consumer acceptability was the best at 6% level. The increasing of the supplementation to more than 6%, e. g. 7, and 8% levels caused a drop in the overall quality. There were significant differences in colour and highly significant ones in taste, flavour and texture due to differences in the supplementation level. The presence of all essential amino acids in significant quantities suggests an importance of supplementation of salt biscuit in human nutrition.