PVA, Starch/PVA, and Starch/PVA/sugar samples of different
concentrations (10, 20, 30 and 40 % wt/wt) were prepared by casting
method. DSC analysis was carried; the results showed only one glass
transition temperature (Tg) for the samples involved, which suggest
that starch/PVA and starch/PVA/sugar blends are miscible. The
miscibility is attributed to the hydrogen bonds between PVA and
starch. This is in a good agreement with (FTIR) results. Tg and Tm
decrease with starch and sugar content compared with that for
(PVA). Systematic decrease in ultimate strength, due to starch and
sugar ratio increase, is attributed to (PVA), which has more hydroxyl
groups that made its ultimate strength higher than that for
starch/PVA, and starch/PVA/sugar blends. It is observed from water
uptake tests that the solubility time decreases with starch ratio; it is
attributed to decrease in hydroxyl groups caused by PVA ratio
decrease. The inter- and inter-molecular bonds of the hydroxyl
groups enhanced the solubility process of the starch/PVA blends in
water. The water immersion causes hydrogen bonds (inter and
intermolecular bonds) to decompose, that increases the film
solubility. Water absorption and capacity of degradability are most
important in biodegradable materials. The results suggest the samples
that have undergone investigation, can be used for shopping, and
food packaging.
The study of soil burial for the sample at (3cm) depth, and at (13cm)
depth has exhibited weight loss increase with soil burial time. The
biodegradability rapidly increases at the first (6-7) weeks; it is found
that the weight loss at (3cm) depth is greater than that at (13cm) that
was attributed to the differences in the availability of oxygen ratio. It
is found that PVA undergoes lowest weight loss, the weight loss
changes with starch, and sugar content. In dry soil, the weight loss is
lower. The results proved that the biodegradation decreases with soil
burial time after seven weeks of burial. It is concluded that the
samples involved are biodegradable material that can be used for
packaging applications and biologically friendly synthetic polymer
blends to solve the solid waste accumulation problem.
The concept of environmental debt, which has several dimensions, emerged in the nineties. One of these dimensions is spatial, referring to the debts that southern countries sustain due to the extraction of natural resources and environmental damage inflicted upon northern countries. Another dimension, the temporal dimension, concerns the environmental debts that current generations owe to their predecessors. That means past generations are culpable for overuse of natural resources and mismanagement. The debt issue is complex, despite many mechanisms to resolve it. Most important are the recently introduced environmental bonds, an important step forward in the field of sustainable financing of environmental debts.
The major of DDoS attacks use TCP protocol and the TCP SYN flooding attack is the most common one among them. The SYN Cookie mechanism is used to defend against the TCP SYN flooding attack. It is an effective defense, but it has a disadvantage of high calculations and it doesn’t differentiate spoofed packets from legitimate packets. Therefore, filtering the spoofed packet can effectively enhance the SYN Cookie activity. Hop Count Filtering (HCF) is another mechanism used at the server side to filter spoofed packets. This mechanism has a drawback of being not a perfect and final solution in defending against the TCP SYN flooding attack. An enhanced mechanism of Integrating and combining the SYN Cookie with Hop Count Filtering (HCF) mech
... Show MoreThe heavy metal cadmium is extremely harmful to both humans and animals. Zinc supplementation protects the biological system and reduces cadmium-induced toxicity. This study aimed to determine whether zinc chloride (ZnCl2) could protect male mice with the damaged liver induced by cadmium chloride (CdCl2). The protective role of zinc chloride and expression of the metallothionein (MT), Ki-67, and Bcl-2 apoptotic proteins in hepatocytes were studied after subchronic exposure of mice to cadmium chloride for 21 days. Thirty male mice were randomly categorized into 6 groups (5 mice/group) as follows: a control group that did not receive any treatment, a group given ZnCl2 at 10 mg/kg alone, and two groups received ZnCl2 (10 mg/kg) i
... Show MoreThe present study aimed to investigate the effect of re-operations engineering business in continuous improvement, as the rapid development of service activities generally private and the great diversity in the goals of its operations and programs of the university and the service has led to the increasing importance of re-operations engineering business as well as continuous improvement so began to study the relationship between the re engineering and continuous improvement of university service, and applied study on a sample of professors from the faculties of administration, economics and law. Find and reach to several conclusions, notably that the preparation of the teaching staff training sessions on how to use modern teaching
... Show MoreThe soft sets were known since 1999, and because of their wide applications and their great flexibility to solve the problems, we used these concepts to define new types of soft limit points, that we called soft turning points.Finally, we used these points to define new types of soft separation axioms and we study their properties.
The main goal of this paper is to introduce and study a new concept named d*-supplemented which can be considered as a generalization of W- supplemented modules and d-hollow module. Also, we introduce a d*-supplement submodule. Many relationships of d*-supplemented modules are studied. Especially, we give characterizations of d*-supplemented modules and relationship between this kind of modules and other kind modules for example every d-hollow (d-local) module is d*-supplemented and by an example we show that the converse is not true.
Let R be associative ring with identity and M is a non- zero unitary left module over R. M is called M- hollow if every maximal submodule of M is small submodule of M. In this paper we study the properties of this kind of modules.
A new class of generalized open sets in a topological space, called G-open sets, is introduced and studied. This class contains all semi-open, preopen, b-open and semi-preopen sets. It is proved that the topology generated by G-open sets contains the topology generated by preopen,b-open and semi-preopen sets respectively.
Weibull Distribution is one of most important distribution and it is mainly used in reliability and in distribution of life time. The study handled two parameter and three-parameter Weibull Distribution in addition to five –parameter Bi-Weibull distribution. The latter being very new and was not mentioned before in many of the previous references. This distribution depends on both the two parameter and the three –parameter Weibull distributions by using the scale parameter (α) and the shape parameter (b) in the first and adding the location parameter (g)to the second and then joining them together to produce a distribution with five parameters.
... Show MoreLet R be associative; ring; with an identity and let D be unitary left R- module; . In this work we present semiannihilator; supplement submodule as a generalization of R-a- supplement submodule, Let U and V be submodules of an R-module D if D=U+V and whenever Y≤ V and D=U+Y, then annY≪R;. We also introduce the the concept of semiannihilator -supplemented ;modules and semiannihilator weak; supplemented modules, and we give some basic properties of this conseptes.