Al-Qadisiyah Journal for Engineering Sciences

A chimney dependent solar crop dryer (CDSCD) was designed and developed. Design of Experiments (DOE) was used to carry out experiments using a statistical three level non randomized factorial experimental design in Minitab statistical software version 19.0. The effect of three drying parameters, roof angle (º), Inlet gap size (mm), and time (h) on dryer inlet mass flow rate (kg/s) and moisture content (%) were studied. The regression results showed that there was a satisfactory fit of the model variability for both dryer inlet mass flow rate and crop moisture content. The p-value for each parameter was less than 0.005, which is statistically significant. The R-squared (R2) value was 94.67% for inlet air mass flow rate study and 99.72% for moisture content. It was observed that the optimal values for achieving a low moisture content response (≤ 24%) were roof angle of 81º, inlet to outlet cross-sectional area ratio of 1.08768:1 and a minimum drying time of 24 hours while the optimal values for achieving high inlet air mass flow rate (≥ 0.357 kg/s) were roof angle of 51º, inlet to outlet cross-sectional area ratio of 1.08768:1 and a minimum drying time of 5 hours. The findings could be implemented and utilized for achieving optimum ventilation and drying performances to refine dryer (CDSCD) design.

Planetary gear trains (PGTs) are used in a wide range of mechanical applications. Graphs are used to represent PGTs. PGTs are classified into single-planet and multi-planet gear trains depending on the number of vertices in the second level of the graph. In this paper, a novel method for synthesizing PGTs up to the second level is developed. The first step in the synthesis process is the enumeration of spanning trees. A combinatorial analysis is then used to obtain the link assortment arrays and categorize them into families. Based on the parent graphs and spanning trees, the geared graphs are generated for each family. For simplicity, the steps of the newly developed genetically compatible graphing method are applied to 5-link, 1-DOF planetary gear trains. The synthesis steps are programmed in MATLAB.

Reinforced concrete, RC beams subjected to shear failure which is the most unwanted failure mode due to speed progress is studied numerically. Therefore, the effective design of beams is necessary because of the sudden failure types of these beams in shear. The minimum shear reinforcement ratio of RC beams must be provided around the longitudinal rebars. Thus, the stirrups with different patterns have a significant benefit for improving the RC beam. In this paper, the performance of specimens with different spiral stirrups using ANSYS programs is investigated by comparing them with conventional stirrups of RC beams. One statement on the experimental results has been obtained from previous research Karayannis et al. [17]. The behaviors of these experimental beams are compared with finite element analysis of the identical beams. It is found that the behaviors of the experimental beam in comparison with the behaviors of the numerical beam are slightly different. Based on the FE analysis, the shear strength results demonstrated the mean accuracy and standard deviation of about 0.994 and 0.028, respectively, compared with the experimental test. Furthermore, the curve determined from FE analysis is consistent with the experiment data. The results give knowledge about the importance of spiral stirrups of the beam, and the most effective method among the investigated cases.

Removal of COD from hospital wastewater generated from Al- Diwaniyah hospital located in Iraq was achieved using graphite–graphite electro-Fenton (EF) system. The effect of various operational parameters on the COD removal efficiency was investigated based on response surface methodology (RSM). Optimal conditions were current density of 20mA/cm2, FeSO4 concentration of 0.697 mM and time of 48.687 min. At these conditions COD elimination efficiency of 97.964 % was achieved at a specific energy consumption of 10.78 kWh/kg. The results indicated that time had the least effect on the COD removal efficiency, while the impact of current density had the greatest effect, followed by the FeSO4 concentration. The adequacy of the model equation was confirmed by its high R2 value (99.62%). The present study shows that graphite–graphite EF system was an efficient tool for removing of COD from hospital wastewaters.

Due to the characteristics of Deoxyribonucleic acid DNA chain which contains a very wide range of parallelism mechanism, and the computing processing speed can arrive at 1 billion times per one second. It is worth only a billionth of a traditional computer. It became the focus of the attention of researchers in the field of encryption. The aim of this study is to find an efficient and safe algorithm for data encryption as well as decryption. A symmetric novel method is proposed in this paper depends on DNA encryption by applying a mixture of DNA oligonucleotide and new development of algorithm technology steps. It includes encoding each character to a predefined decimal number, converting it to its equivalent binary number and then converting it into DNA coding. Finally, converts each code of DNA to a number that represents a row and column numbers. Simulation all all text (words) is executed in parallel by using Visual Basic programming, obtained an excellent encoding result in terms of time because all the characters, so the algorithm is able to process the largest number of data, all of them encode at the same time. An efficient, fast and highly encoding scheme has been obtained due to the complete executing parallelism of the DNA-based algorithm.

This research studies the influence of using SiO2 nano-particles of 50nm in a Vapor Compression Refrigeration System (VCRS), along with Poly-alkylene Glycol (PAG) oil and R-134a mixed to create a nano-refrigerant. The methodology used in this work, the nano-particles were performed in three different concentrations (0.1%, 0.3%, and 0.5%) and mixed with 200ml of PAG oil. A VCR system was built at the mechanical engineering department laboratory in Al-Qadisiyah University. In order to study the Coefficient of Performance (COP) and the consumed energy by the compressor in the two cases of adding the nano-particles and using a pure refrigerant. The paper showed an increase in the system\'s COP from 2.3 to 2.81 when using a concentration of 0.5% of SiO2/PAG oil/R-134a, increasing the refrigeration effect and decreasing the consumed power.

Ziziphus Spina-Christi bark and other natural debris may be found in abundance in the nearby area. The mechanical qualities of all of these waste natural resources are outstanding, and they may be utilized more professionally to create composite materials for a variety of applications. Epoxy resin modified with organic natural particles such as Ziziphus Spina-Christi bark powder has been used as reinforcements in polymer matrixes instead of non-degradable synthetic reinforcement such as glass, carbon, or aramid. The tensile, impact and flexural characteristics of the Ziziphus Spina-Christi bark particles enhanced epoxy resin are examined in this publication. This paper studies the effects of weight fraction (3, 5, 7 & 9%) on the characterization of composite materials. The results show that the mechanical characterization of epoxy improved when added 7% from the particles of Christi. Where the hardness increased up to 77 (Mpa). Also, the impact strength reached 8.7 (KJ/m2 ) with a 7 wt% filler added, and the tensile strength increased from 18 (MPa) to 45 (MPa). The flexural strength of pure epoxy is 160 (MPa), and it increases linearly with the addition of Ziziphus Spina-Christi bark to 173 (MPa).

Electrochemical treatment methods are frequently used to remove a wide range of pollutants from wastewaters generated by domestic and industrial operations. This work aims to investigate the impacts of using monopolar and bipolar connection modes of an electrocoagulation reactor (ECR) used to remove multi-toxic metals from synthetic wastewater. The present design of the ECR involves concentric-multi-cubic (CMC) aluminum electrodes with an activated area of 360 cm2. The anode electrodes are perforated to be light-weight and decrease the amount of anode consumption as well as the increase of oxygen bubbles released that were assisting the buoyancy process of light-pollutants toward the surface of the solution in addition to the hydrogen bubbles are released from the plane electrodes of the cathode. The synthetic wastewater contains 100 ppm of each Pb, Cd, and Cu ion under the effects of pH of 7, applied current of 1.4 A (which equals remove to 3.88 mA/cm2), NaCl of 2 g, 300 rpm of stirring speed, and reaction time of (0-90 min). The core results proved that the bipolar connection mode (BCM) was more effective than the monopolar connection mode (MCM) in toxic metal-wastewater treatment. After 60 min of the reaction time, the highest removal efficiencies of these metals After a reaction timeof 60 min, the highest removal efficiencies of Pb, Cd, and Cu metals obtained via the BCM system were : 99.91%, 99.68%, and 99.14%, respectively 99.91%, 99.68%, and 99.14%, respectively. While they achieved 60.55%, 64.24%, and 89.55% via the MCM system , . re spectively The present new design of electrodes using the bipolar system was more reliable in wastewater treatment containing toxic metals with significantly low values of electrical energy consumption, electrode consumption, and cost-effectiveness

The mixed convection investigation of various design parameters utilizing finned pipes in the cylindrical enclosure has been investigated computationally. Various geometries of fins are used (circular and longitudinal). The effect of fins number (12-16), aspect ratio (1.83-2.7), radius ratio (2-3) and fins geometry have been introduced within the present study. The observations show that when Richardson number=0.5 and 5.5, the heat transfer decreases by 12.22% and 7.777%.,. Values of the Nusselt number rise as the number of fins increases. While, when the Rayleigh number is high, no noticeable variations in the numbers of fins (12 and 14). The purpose of using fins is to increase the surface area of heat transmission. The highest heat transfer improvement is shown to be 4.2%, when log (Rayleigh)=7.342 and 16 fins are utilized. The radius ratio does not affect Nusselt number throughout the whole Richardson and Rayleigh in both hot and cold locales. The turbulence sub-layer does not affect the free stream behaviour for different Richardson number. In the case of high Richardson number, the geometry does not influence the Nu. Longitudinal fins do not have dead zones, unlike circular fins, which have channelling generated by geometrical arrangement. To reach thermal equilibrium in a cold environment, the Nu in rectangular fins was reduced by 18% as compared to circular fins with a low Richardson number. Flow development would increase the impact of channelling. The heat transfer improvement decreases as the number of fins increases, as illustrated in temperature and velocity profiles for various values.

The present study is attempted to investigate the influence of multicomponent Ni-alloy (BNi-2) on the hydrogen embrittlement (HE) behaviour of AISI 1018 steel by using cathodic protection and tensile test. The results show that the HE indexes (HEI) decrease notably when AISI 1018 steel is coated with BNi-2 alloy by DC sputtering process. This coating processes leads to decrease in HE susceptibility of the AISI 1018 steel, which can be rationalized to the enhancement in corrosion resistance and the decrease in hydrogen absorption of the AISI 1018 steel after coating. The tensile strengths of bared samples were decreased with increasing charging time until 24 hours when stable at values 350 MPa. while the coated samples showed an increasement in the tensile strength from 570 MPa to 750 MPa. stabilization in strength at value of 600 MPa was observed after exceeding 48 hours. Also, the tensile test for uncoated specimens indicated a clear reduction on the modulus of elasticity compared with other coated ones.