Misan Journal of Engineering Sciences

This research is studied the possibility of reusing PVC pipes wastes as partial replacement
of sand within concrete mixture. In this study, the fine aggregate is replaced with PVC at dosages
1.25%, 2.5%, 3.75% and 5% by weight of sand with superplasticizer (SP) admixture. The mechanical
properties are evaluated, which included compressive strength, splitting tensile strength, and flexural
strength, in which for each one, 60 specimens are tested for water to cement ratios 0.41 and 0.53. Also,
the effect of these wastes on the strengths and serviceability of concrete beams are investigated by
testing three simply supported reinforced concrete beams of dimensions 150×200×1400 mm. It is
concluded that w/c ratio of 41% of the replacement of fine aggregates with 1.25% PVC particles
showed the optimum results for compressive, tensile and flexural strengths, namely 31.66 %, 6.45%,
and 31.23%, respectively, more than control mixture. The beam specimen that contain on 1.25% of
PVC particles showed an increase in ultimate load by about 6.06% compared to the reference beam.
While the hybrid cross section beam showed a relatively small reduction in ultimate load compared to
reference beam, i.e, 14.5%. Thus with hybrid sections considerable amount of plastic wastes could be
recycled with relatively small reduction in ultimate capacity of beams.

This paper aims to study the effect of concrete confining using a new style of internal
closed stirrups and longitudinal steel bars along with the middle third of the beam length of the beamcolumn joints. Also, the influence of concrete compressive strength was investigated using three types
of concrete normal strength concrete (NSC), high strength concrete (HSC), and steel fiber concrete
(SFRC). Nine reinforced concrete specimens with the same dimensions are divided into three groups
according to the concrete type with different reinforcement details in the middle third of the
specimen’s length. Four specimens with (NSC) represent the first group, while three specimens consist
in the second group with (HSC). Steel fiber of 2% was used in two specimens of the third group
(SFRC). The test results showed that using additional reinforcement steel bars as a closed stirrup
arranged about the neutral axis improved the flexural strength and enhanced the load-carrying capacity
for the reinforced concrete joints. The ultimate capacity of the joints increased by a range (34 to 50) %
more than the control specimen. The ultimate strength was also increased for the specimens due to
using high-strength concrete with a range (of 13 to 66) % compared with the specimen of normal
compressive strength.

Bonding between various construction materials is the key to developing smart composite
action within structural elements, likewise beams, slabs, columns, etc. The push-out test is best to
determine shear bonding strength and related slip and uplift response in composite components. Pushout test almost could be considered a smart, efficient technique to predict the shear bonding strength
between various construction materials in the laboratory. There is no code specification related to the
push-out test for adhesive shear bonding. This study introduces a suggested mode regarding
continuous shear bonding field in concrete-metal composite elements, which adopts the most common
configuration considered in investigating the mechanical fastener's shear resistance. An experimental
program is considered. The results depict that the failure loads are changed from (55.7 kN) to (58.01
kN) as the thickness of the adhesive epoxy layer increased from 3 mm to 6 mm, and the results related
to the behaviour of load - slip an exponential equation normalizes response of adhesive epoxy layer.
Generally, the obtained results confirmed that the introduced continuous shear bonding field could be
considered a more proper technique than the mechanical technique. The slip remains very small during
the test.

The imperative need for alternative approaches to organ transplantation, replacing or
regenerating damaged tissues is the key driving force for the remarkable development in tissue
engineering. It can be precious in saving people who suffer from the critical shortage of organ
donation. Such a strategy can repair injured body parts and tissues by using biomaterials, cells, and
bioactive agents. Even though numerous scaffold manufacturing techniques have been available for
bone regeneration, the three-dimensional (3D) printing approach can provide scaffolding with delicate
features that may not be obtainable in other manufacturing strategies. For instance, when a 3D printer
is used, it is possible to easily adjust scaffold pore architecture and size, porosity, and material
alignment, forming customizable and defect-fillable scaffolds, which helps control the mechanical
behavior of cellular response. The most prominent material used in scaffolding and printing is
polycaprolactone (PCL), owing to its considerable potential and capabilities. It has favorable
properties for the fabrication of bone tissue engineering scaffolds, such as biocompatibility,
viscoelasticity, and affordability. Nonetheless, some inherent drawbacks of this polymer that limit its
use in this field are detected, including inadequate mechanical performance, cell adhesion,
osteoinductive deficiency, hydrophobicity, and low degradation rate. The incorporation of other
materials within this polymer to form composites, on the other hand, can contribute to alleviating the
negative influence of the PCL's undesirable characteristics. Improving the mechanical and biological
behaviors of PCL-based scaffolds allows these structures to be utilized for tissue engineering since
such composites can promote cell adhesion and differentiation, mimic anatomical characteristics of
native bone, and can have superior mechanical performance. In this review, the latest advancements in
printing intricate geometries 3D PCL-based composites using bioactive ceramics and/or biopolymers
by fused deposition modeling (FDM) for bone tissue engineering will be explored, particularly from a
morphological, mechanical, and biological perspective.

Accurate assessment of oil and fault diagnostics electrical power transformer insulation for lifelong
endurance are the key issues addressed in this research. The durability of a transformer is significantly determined
by the quality of its insulation oil, which deteriorates over time due to temperature fluctuations and moisture
content. Protecting transformers from potential failure through the early and precise diagnosis of faults and efficient
assessment of oil quality during the actual conduct of the operation can avoid sizeable economic losses. The ANFIS
Expert System that uses intelligent software plays an important role. The dissolved gas analysis (DGA) in oil is
reliable for diagnosing faults and assessing insulation oil quality in transformers. Transformer power plant
protection teams often suffer sudden breakdowns that lead to massive damage and huge financial losses. The oil in
transformers must be appropriately treated to circumvent such failures. In this research, an ANFIS Expert System
was used to diagnose faults and assess insulation oil status and quality in power transformers. by the Rogers ratio
method depending on the DGA in oil a suitable treatment was identified .The graphical user interface from the
MATLAB environment was used and proven effective for fault diagnosis and oil quality evaluation. The training
algorithm can assess oil quality according to the specifications of the IEEE standard C57-104 and the IEC standard
60599.

This paper aims to prepare PMMA sheets (Polymethyl methacrylate sheets) reinforced
with SiO2 nanoparticles (Silicon oxide nanoparticles) to obtain samples for tribological and
mechanical tests. PMMA reinforced sheets are prepared by three methods; dissolving, pressing, and
casting. In the first method, the pure PMMA granules were dissolved with an organic solvent. The
SiO2 nanoparticles were dispersed using a magnetic stirrer. Then, the solution was poured into a
glassy mold. In the second method, pure PMMA powder was used, and SiO2 nanoparticles were
dispersed using a nanoparticle disperser device; then, the mixture was placed in a metal mold and
pressed by a thermo-hydraulic press. While in the third method, pure PMMA resin and hardener were
used, and SiO2 nanoparticles were dispersed using an ultrasonic probe machine, and then the mixture
was poured into a glassy mold. The three preparation results showed that the obtained sheets were free
of bubbles and that their surfaces were of excellent smoothness and could be cut using a laser to obtain
the samples required for tribological and mechanical tests such as tensile test, impact test, wear test,
surface hardness test, surface roughness test, and scratch resistance test and others.

Operating the power system in optimal way and keeping it safe and reliable is very
important in power systems planning and operation. The power system currently has a large variety
of power plants that operate with different kinds of fossil fuel or use renewable energy to produce
power. As the demand on electricity is fluctuated, utilities are obligated to provide consumers with
power at any time during a day. Power system operators try to supply electricity in an economic
operation by turning on the cheapest generating units and turning off the most expensive ones at offpeak value of the load. Finding the optimal combination of units to supply forecasting load is called
unit commitment problem (UC). The second step of the optimization problem is finding the optimal
output power from each committed unit, which known as economic dispatch (ED). The main benefits
of solving the unit commitment problem and economic dispatch are to minimize generation cost over
the objective period horizon while applying all system constraints that come from generating units’
limits and the transmission system’s characteristics, as well as to verify the balance between power
generation and power demand. While, the optimal power flow (OPF) tries to find the optimal dispatch
for the whole power system, but by taking into account all systems constrain, such as voltage security
and transmission line limit. The optimal power flow can control many variables to find the optimal
operation of the system, like a transformer tap changer, phase shifter, switched shunt, and load
adjustment. In this paper, power system simulator for engineering (PSS®E) is used to solve unit
commitment, economic dispatch, and optimal power flow. The implementation is performed on IEEE
30-bus system for a 24-hour period. In the first stage, the UC, ED, and OPF were solved for the
systems without including wind power generation. In the second stage, UC, ED, and OPF were solved
by including a wind-power farm with 100 MW rated power connected to the system. The solution is
based on 24-hour wind data forecasting, and 24-hour power demand's prediction.