Optimal control methods are used to get an optimal policy for harvesting renewable resources. In particular, we investigate a discretization fractional-order biological model, as well as its behavior through its fixed points, is analyzed. We also employ the maximal Pontryagin principle to obtain the optimal solutions. Finally, numerical results confirm our theoretical outcomes.

The Mesopotamian marshlands faced a massive destruction from many years and this lead to effect to ecosystem. In this study a survey was made on the physical chemical and heavy metals characteristics and microbiological analysis of AL Chibaish marsh during the two months. Water analyses revealed unacceptable values for almost all physiochemical and biological properties, according to WHO standard limits for drinking water. Almost all major ions and heavy metal concentrations in water showed a distinct decreasing trend at the marsh outlet station compared to other stations. In general, major and minor ions, as well as heavy metals exhibit higher concentrations in location 1 than in location 3. The concentrations of heavy metals in water show

Aim To develop a low-density polyethylene–hydroxyapatite (HA-PE) composite with properties tailored to function as a potential root canal filling material. Methodology Hydroxyapatite and polyethylene mixed with strontium oxide as a radiopacifier were extruded from a single screw extruder fitted with an appropriate die to form fibres. The composition of the composite was optimized with clinical handling and placement in the canal being the prime consideration. The fibres were characterized using infrared spectroscopy (FTIR), and their thermal properties determined using differential scanning calorimetry (DSC). The tensile strength and elastic modulus of the composite fibres and gutta-percha were compared, dry and after 1 month storage in

In this work, silver (Ag) self-metallization on a polyimide (PI) film was prepared through autocatalytic plating. PI films were prepared through the solution casting method, followed by etching with potassium hydroxide (KOH) solution, sensitization with tin chloride (SnCl₂), and the use of palladium chloride (PdCl₂) to activate the surface of PI. Energy-dispersive X-ray analysis (EDX) showed the highest peak in the (Ag) region and confirmed the presence of AgNPs. The diffraction peaks at 2θ = 38.2^°, 44.5^°, 64.6^°, and 78.2^° represented the 111, 200, 220, and 311 planes of Ag, respectively. The FT–IR an

Lipoxygenase was extracted from the cup of Pleurotus ostreatus ( Jaq : Fr ) oyster mushroom for the first time in Iraq, and purified homogeneously through precipitation with 40% saturation of (NH4)2SO4 as a partial purification then loaded on DEAE-Cellulose (Diethyl amino ethyl Cellulose) ion-exchange chromatography column and then the highly active elution parts have been passed through gel filtration column with Sephacryl S-300 as a final purification with 804 (U/mg protein) specific activity, 11.32 fold of purification and 36.54% yield . The molecular weight of the enzyme was estimated to 74 KDa by gel filtration Sephacryl S-300 column and the isoelectric point for enzyme was 5.3. The optimal pH for lipoxygenase activity and stability

Four batches of sertraline HCl microspheres were prepared using a poly (D-L-lactide-co-glycolide) (PLGA) polymer ( Mw. 9, 27, 30 and 83 KDa) as  a delivery system. The microspheres were prepared by a dispersion/solvent extraction-evaporation method and characterized for drug loading by UV, particle size by laser diffractometry and surface morphology by scanning electron microscopy (SEM). The in vitro sertraline HCl release was studied. Spherical microspheres with a mean diameter of 21 to 26 µm loaded with 24.6 – 38.2% were produced. The in vitro drug release was shown to be depend on polymer molecular weight and also on the drug loading. Differential scanning calorimetry (DSC) was employed to investigate the physical state

Silicon nanowire arrays (SiNWs) are created utilizing the metal-assisted chemical etching method with an Ag metal as a catalyst and different etching time of 15, 30, and 60 minutes using n-Si (100). Physical properties such as structural, surface morphology, and optical properties of the prepared SiNWs are studied. The diameter of prepared SiNWs ranged from 20 to 280 nm, and the reflectance in the visible part of the wavelength spectrum was less than 1% for all prepared samples. The obtained energy gap of prepared SiNWs was around 2 eV, which is higher than the energy gap of bulk silicon. X-ray diffraction (XRD) has diffraction peaks at 68.70^o for all prepared samples. The heterojunction solar cell was fabricated based on the

CdTe nanorods were prepared by using aqueous chemical synthesis. The influences of reaction time (1-3 hours) on the optical and structural properties were studied. The UV-visible absorption spectrum reflects a wide absorption range in the visible spectrum. The energy gap calculations show decrease in the energy gap with increasing reaction time. The SEM images show that the CdTe appears as flower of nanorods-like.

Iraqi kaolin was used for the preparation and characterization of NaY zeolite for biodiesel production via esterification reaction. Oleic acid was used usually as a typical simulated feedstock of high acid number for the esterification reaction.

   The chemical composition for the prepared Nay zeolite is as following:  (Ca₂.6Na₁.K_0.1)(Al₆.3Si₁₇.₇)O₄₈.16H₂O, the silica to alumina ratio in the prepared catalyst was found equal to 2.6 and Na₂O content was 12.26 wt. %, with relative crystallinity equal to 147.4 % obtained by the X-ray diffraction. The surface area result shows that the prepared catalyst has 330 m²

The n-type Au thin films of 500nm thickness was evaporated by thermal evaporation method on p-type silicon wafer of [111] direction to formed Au/Si heterojunction solar cell. The AC conductivity, C-V and I-V characteristics of fabricated c-Au/Si diffusion heterojunction-(HJ) solar cell, has been studied. The first methods demonstrated that the AC conductivity due to with diffusiontunneling mechanism, while the second show that, the heterojunction profile is abrupt, the heterojunction parameters have been played out, such as the depletion width, built-in voltage, and concentration. And finally the third one show that the c-Au/Si HJ has rectification properties, and the solar cell yielded an open circuit voltage of (Vic) 0.4V, short circuit c