---

In this paper, some applications of the Method of Least Squares (MLS) for the solution of various problems in electromagnetics engineering is briefly reviewed. Here, MLS is employed for the solution of various problems such as solution of equations, curve fitting to measured data, generalized Fourier coefficients, linear operator equations, inegro-differential equations, electrostatics and magnetostatics problems, boundary value problems (by the Least Square Boundary Residual Method LSBRM), design of impedance transformers and matching by step and tapered lines, optimum design of multihole directional couplers, coupled-line couplers, branch line couplers, ring couplers, analysis of wire antennas, antenna pattern synthesis, array synthesis and scattering. In this study, it becomes clear that MLS can be applied to devise effective numerical algorithms for the analysis and design of problems in the subject areas of radiation, scattering, antennas, microwaves, engineering mathematic, etc. Some papers and books published in the area of MLS applications for the analysis and design of problems in electromagnetics engineering are grouped and presented in references.

---

The environmental scanning electron microscopy (ESEM) is a new development in the field of electron microscopy. In this study ESEM has been used to study the structure of veal semimembranosus muscle. Four treatments, raw (control), conventional heating, domestic and industrial microwave heating, were observed using ESEM. The temperature used in conventional heating was 163 0C. Frequency applied for microwave heating was 2450 MHz with two wattage levels of 700 (domestic microwave) and 12000 (industrial microwave). All samples were heated to 70 0C internal temperature. Occasional cracks across the individual muscle fiber and shrinkage were present in all images of the structure for heated muscle. Erosion at the edges of muscle fibers was clear and increased with continued heating. A gap between perimysium of each muscle bundle was effected with the domestic microwave samples in cross section. This phenomenon was more apparent in industrial microwave heating and the depth of gap between perimysial collagenous fiber is more than that in domestic microwave heating. More damage was observed in the connective tissue network for conventional heating as compared with microwave heating. Denaturation and distortion of connective tissue caused more damage during longer time of conventional heating. Surface damage in structure of semimembranosus was not observed in either conventional heating or the low powered microwave heating. Rapid increase of heat and penetration of the microwaves, at the 12000 wattage level, caused granulation and separation of some parts of the muscle fibers.

---

Encapsulation process is a method by which sensitive materials (core) are covered with polymeric materials (wall). As most encapsulation techniques need complicated equipments, long laboratory works and are expensive, therefore, in this study a new technique is utilized for producing microcapsules at a very short time and low cost. This technique is based on the difference between dielectric constants of core and wall materials as well as electromagnetic energy. Edible citric acid crystals (core) were combined with some coating materials such as salab, gum tragacanth, refined starch, sucrose, guar gum, agarose, gelatin, fibrosis carboxymethylcellulose (CMC), inulin, low and high methoxyl pectin (LMP & HMP), casein, and sorbitol at ratios about 1:2 up to 1:100 (core:wall). Each mixture was treated up to 600 seconds (depending on the type of wall materials) at various microwave power intensities (10–100 %). Afterwards, the prepared microcapsules were separated by distinct (with defined mesh No.) sieves and their apparent structure and quality were evaluated using binocular and their photographs were taken by a microscope equipped with digital camera. Our findings revealed that amongst the materials were examined only inulin, casein , LMP (9.5%), fibrosis CMC, and sorbitol were able to produce high quality as well as highly efficient microcapsules, respectively. In addition, the highest coating efficiency was seen at 100% microwave power intensity (1200W) at 1:10 mixing ratio. Moreover, the optimum microwave treating time for casein, inulin, fibrosis CMC, LMP (9.5%), and sorbitol was 400, 75, 400, 100, and 100 seconds, respectively.

---

Oxidative stability of oils, fats and fatty food products can be affected by many factors such as oxygen, light, heat, metal ions and enzymes used and finally it brings about oxidative corruption. This study has been done to survey the role of Dorema aucheri extract in oxidative stability of fish oil (under microwave heating) and comparising that with BHT synthetic antioxidant. Concentrations of 250 and 500 ppm extracts of Dorema auchri and BHT 200 ppm were added to fish oil and a fish oil sample without the addition of antioxidant was considered as control, Then they were sampled after putting in microwave at time periods 0, 3, 6, 9, and 12 minutes. Chemical oxidative indicators (peroxide, free fatty acids and thiobarbituric acid) were surveyed. According to the results, in all times putting in microwave the amount of peroxide, free fatty acids and thiobarbituric acid  in the treatments that contained extract, were lower than the control treatment, but were higher than the treatment that contained  BHT. A significant difference wasn^'t seen among the treatment that contained 250 ppm of extract and the treatment that contained BHT (p>0/05). According to the results, because of significant difference of samples contained extract with control sample and the lack of significant difference sample containd 250 ppm extract with BHT, it would be expected that Dorema aucheri  extract as antioxidant can be used  in food industry in maintenace of fish oil.

---

  Over the past few decades, microwave processing and its high potential capabilities has attracted food scientists where they preferred to replace the old and time-bearing prevalent methods with this swift and simple method. Application of microwaves for microencapsulation is an innovative and new method in which the core and shell were combined at an appropriate ratio and treated by microwaves in order to microencapsulate the core material by coating one. In this research, the citric acid powder at two various size (100–500 and <100 micron) was microencapsulated at different ratios (1:5 and 1:10) by casein and inulin, at various microwave powers (up to 1200 W) for 50 to 250 seconds. Findings of qualitative evaluation of microcapsules by laboratory binocular, scanning electron microscope photographs as well as particle size analysis illustrated that the optimum conditions namely ratio and microwave power for microencapsulation of citric acid by both casein and inulin were 1:10 and 1200 W with slightly different treating time where it was 150 and 50 seconds, respectively. In the next step, these two microcapsules along with uncoated citric acid powder as well as commercial microcapsules of citric acid were added to the ribbon type chewing gum and the sensory evaluation regarding texture, stability of sour taste and aftertaste was done by a semi-trained taste panel. The findings revealed that in terms of sour taste stability and aftertastes, the chewing gum containing citric acid microencapsulated with inulin had highest score whereas with regard to texture one treated with the commercial microcapsules gained the highest score. In addition, the lowest sensorial scores were belonged to samples which treated by citric acid microencapsulated with casein. Finally, for the first time on a real foodstuff the practical capability of this novel, simple, low cost, and rapid microencapsulation technique was confirmed.

---

Bacteriorhodopsin (bR) is a membrane protein that acts as a light-driven proton pump in Halobacterium salinarum. This protein contains seven transmembrane α-helical subunits, helices A–G, one beta-sheet and a retinal chromophore. Studies show that bR have the property of absorbing the microwave. Among several methods molecular dynamics simulation (MD) is the most systemic approach. With this method we can study structural changes and dynamic of macromolecules. In this project, we use modeling and molecular dynamic simulation. To obtain more accurate structures after the equilibration a 15 ns MD simulation was done. After that, in order to find the effective sites of microwave absorption on bR a production run was performed with applying electric field in the time intervals of 786 ps that is equal to one sinusoidal frequency at microwave spectrum. At last, conformational changes under effect of sinusoidal wave has been assigned the effective sites of microwave absorption in the protein. Our study shows that microwave in the frequency of 8 GHZ and the time interval that mentioned above, cannot make significant changes on the protein. In the other hand, we have seen some reversible changes in Beta-sheet and D, C, B helices.

---

Research subject: Using microwave and ultrasonic waves is a novel method in the petroleum industry that has been investigated for various purposes. Due to polar elements such as oxygen, nitrogen, and sulfur, oil molecules are affected by the electric field of microwave waves and create dipole moments that generate hotspots, increasing the temperature of the oil and breaking down heavy compounds such as asphaltene. Ultrasonic waves eliminate intermolecular forces by creating tiny bubbles and bursting them. It also leads to the breakdown of heavy molecules such as asphaltene.
Research approach: In this study, crude oil was exposed to microwave and ultrasonic radiation, and changes in its properties were investigated. The effects of changing parameters such as power and time on crude oil properties were also examined. Changes in the specific gravity and API can indicate the extent of the breakdown of heavy molecules such as asphaltene and improvement in crude oil quality.
Main results: Using microwave and ultrasonic waves can reduce the viscosity of crude oil by 12.4% and 6% and increase the API by 2.8 and 1.2 degrees, respectively. Asphaltene reduction due to microwave and ultrasonic waves is 9.3% and 4.3%, respectively, indicating the breakdown of these compounds and the conversion to smaller compounds soluble in oil, resulting in improved crude oil quality. The EDS results show an increase in the weight percentage of carbon and the reduction of elements such as oxygen and sulfur, which confirms this issue. Examining crude oil structure under microwave and ultrasonic radiation showed that microwave waves, in addition to affecting straight-chain hydrocarbons, also reduced aromatic compounds. However, ultrasonic waves had a more significant effect on straight-chain hydrocarbon structure.

---

In this study, the drying behavior and the effects of different drying conditions on the trend of moisture loss and effective diffusion coefficient in sweet and sour pomegranate were determined. The best drying model, energy consumption and activation energy values were also determined for the two varieties using microwave drying. Results of regression analysis of mathematical models points to the page model as the one best described the data. Effective diffusion coefficient of pomegranate arils was found to be 3.43´10-10 to 32.05´10-10 m2/s. Activation energy was determined to be 17.22 and 23.83 kJ for sweet and sour pomegranates respectively. In addition, consumed energy consumption drying of for sweet and sour pomegranate arils was 0.167 to 0.383 kW/kg respectively.

---

Aims: The aim of this study was to investigate the effect of cooking (frying and microwave), chitosan additive and freezer storage on the fish fillet in terms of sensory and color evaluation and weight changes.
Methodes: Cultivated fish fillets, frozen at -18 ° C for 4 months. They were then transferred to the Fisheries Processing Laboratory of the Faculty of Fisheries, Gorgan University of Agricultural Sciences and Natural Resources, in the shortest possible time (day 0, day 2 and month 4). The fillets were frozen and cooked in a pan and microwave. The experiment was designed in 4 treatments: T₁ (fried sample without chitosan), T₂ (fried sample containing 1% acid-soluble chitosan), T₃ (microwave cooked sample without chitosan), T₄ (Microwave cooked sample containing 1% acid-soluble chitosan). Fillet weights were measured before and after cooking. Sensory evaluation and colorimetric evaluation of fillets were also performed after cooking.
 
Findings: The use of 1% acid soluble chitosan had no significant effect on sensory parameters and colorimetric factors (p> 0.05). Weight changes in fried fillets increased over time but decreased in microwave-cooked fillets over time.
Conclusion: The use of natural additives such as acid soluble chitosan 1% had no significant effect on the sensory indeces compared to the control group. In terms of colorimetric factors, chitosan had a positive effect on yellowness index. In terms of cooking and having a safe product, it is very important that the weight factor of the microwave cooked fillets is more favorable than the fried fillets.

---

       Scanning Electron microscopy (SEM) has been used for the study of Longissimus Dorsi muscle of lamb. Three treatments including raw (control), conventional heating and microwave heating were used for the samples with the temperatures of 163 C and domestic microwave was applied with the frequency of 2450 MHz and 700 wattages level. In all images were taken for conventional  heating no surface damage was observed. More structural damages were observed in microwave heating  at 700 watages levels. Distribution in microwave heating causes surface damage to muscle fibres and separation of some parts of muscle fibres was also clear. 

---

  In this study, the impact of different drying conditions (4 levels of microwave power 130, 260, 380 and 450 watts and 4 absolute pressure levels 200, 400, 600 and 800 mbar) on drying rate, effective diffusion coefficient, activation energy, and energy consumption of a microwave–vacuum drier for drying the mushroom slices were analyzed. According to the findings, effective diffusion coefficient for mushroom varied between 3.21×10^-9 to 20.005×10^-9 m²/s. In addition, the activation energy based on an Arrhenius based exponential equation was very close to each other for three different methods. In terms of energy consumption, the minimum and maximum quantities were about 0.168 and 0.48 kWh, respectively.  

---

  In this research the effect of microwave thermal treatment with power of 600 w on Longissimus.dorsi (L.d) muscle of camel by 1-3 years were examined. Chemical analysis, mechanical properties and proteins behavior of raw and microwaved samples were compared. Also the cook loss changes in three powers of 300, 600 and 900 w were measured which all of them were followed a zero-order kinetic model. The percentage of fat, protein and ash increased because of high cook loss. Sodium reduced while iron and zinc increased. Shear force and compression force increased in comparison with raw sample. Both Shear force and compression force followed a three-phase curve :(1) rapid toughening, (2) rapid softening, (3) slow toughening. The microstructures of raw and heated samples were also studied. The micrographs showed the rupture of meat structure and connective tissue coagulation. DSC was performed to assess protein denaturation.  

---

  Honey as a medicinal and nutritional material contains about 60% reducing sugar and in liquid and natural state, presents significant handling problem in bulk production operation or consumption due to its viscosity and stickiness. Because of the convenience and ease of use, dried honey has special importance. In this study, feasibility of drying of commercial and noncommercial honeys, with or without water adding, by two methods of freeze drying and microwave drying was evaluated. Also the effect of drying method on chemical properties of the product was investigated. Results showed that not only drying method of honey is effective on quality of dried honey, but also minor differences in the raw honey can affect quality of the product.  Meanwhile, adding water to honey facilitates the drying process. According to the results, the amount of hydroxymethylfurfural (HMF) in noncommercial dried honey using microwave method is much higher than that in commercial honey samples which are dried in a similar way.    

---

In this research In order to use the rice bran extract in the formulation of Fruit Drinks , Three varieties of rice, including tarom, anbar bo and hashemi were selected and heavy metals of them were analyzed and then In order to select the appropriate method of bran extract, Four extraction methods including using subcritical water at a temperature of 100 and 120 ° C, microwave and oven at 100 ° C for the extraction of rice bran were used. After choosing the best method of extraction, physical, chemical, and rheological characteristics of samples were measured and compared. Results of data using SPSS software and one-way ANOVA and the Duncan test were evaluated. Results showed that in using of subcritical water extraction method, increasing temperature increases the amount of extraction of compounds found in rice bran So that Most of the compounds extracted from the above methods is related to using subcritical water at 120° C And the least amount of compounds extracted from rice bran is related to using oven at 100° C. Investigate the rheological properties of the extracts also suggests that All extracts show the behavior of a Newtonian fluid. According to the characteristics of extraction produced from subcritical water at 120° C This method is the best method of extraction Among the extraction methods.    

---

In this research drying kinetics, moisture diffusivity, determination of most appropriate mathematical modeling and activation energy of white mulberry were studied under microwave oven. For determination of most appropriate model, the highest value of R² and the lowest values of c²and RMSE were used. For mathematical modeling, nine empirical models were fitted on experimental data and the best model was selected. The result of regression analysis showed that Midilli model has the best fitting with data. Moreover, the highest and lowest values of moisture diffusivity were obtained as 5.3×10^-6 and 1.42×10^-6 at power of 500 W and 200 W, respectively. Also the values of activation energy and moisture diffusivity in the drying of white mulberry were obtained as 10.83 and 1E-5 respectively, based on an exponential relationship. Finally, the value of specific energy consumption for drying of white mulberry was found between 0.7 to 2.58.  

---

In this study the effect of microwave power on drying behavior, effective moisture diffusion, the best mathematical model of drying, activation energy values and energy consumption of the herb thyme was investigated. Results of regression analysis of mathematical models in MATLAB software points that the Midili model has the best described to the data. Effective diffusion coefficient of herb thyme was found to be between 15.416 and 213.802m²/s. Also the activation energy was determined to be 84.86 W/g for constant drying rate and 100 W/g for effective moisture diffusion. In addition, the minimum and maximum value of specific energy consumption drying of herb thyme was 6.994 to 19.607 kW/kg, respectively.    

---

Root-knot nematodes, Meloidogyne spp. cause 5% of the global crop losses. Silver nanoparticles (AgNPs) are a potentially effective nematicide. There are many methods to synthesize metallic nanoparticles, including using organic compounds, which are clean and environmentally friendly. In the present studies, the efficacy of as-synthesized AgNPs using Malva sylvestris extract (Ms-AgNPs) on egg hatching and mortality of the second-stage juveniles (J2) of M. javanica in vitro, and on the growth parameters of nematode infected tomato plant under greenhouse conditions was investigated. The results showed that increasing Ms-AgNPs concentration decreased the hatching rate and increased the mortality of J2. Ms-AgNPs at 107, 164 and 250 ppm reduced J2 numbers by 30, 50, and 70%, respectively, and were established as lethal doses for nematode control. Ms-AgNPs at a dosage of 250 ppm reduced the number of eggs in the root system and the nematode reproduction factor by 60.4 and 56.3%, respectively, and increased shoot length and shoot fresh weight by 11.2 and 14%, respectively. Ms-AgNPs at a very low concentration reduced the population of M. javanica without causing any harmful effects on tomato. Therefore it can be used in nematode control strategies due to its environmentally friendly composition.

 

---

Phenolic compounds, especially those of plant origin, constitute an essential part of the human diet, and are of considerable interest due to their antioxidant properties. In this study, Ultrasound-Assisted Extraction (UAE), Microwave-Assisted Extraction (MAE), as well as Maceration Extraction (ME) methods were applied for phenolic compounds’ extraction from pistachio green hull. Response surface methodology was employed to optimize the extraction conditions as regards the yield of the compounds. A Central Composite Design (CCD) was employed to investigate the effects of three independent variables, namely liquid-to-solid ratio (8-20 times), temperature (25-65 °C) and time (5-45 minutes) on the dependent variable (level of total phenolic compounds). The results indicated that within the same extraction time, the extraction yield through UAE was higher than those in ME and MAE methods. Correlation coefficients (R2) of the models for UAE, MAE and ME methods were 0.95, 0.96 and 0.94, respectively. The optimal conditions for extraction of phenolic compounds from pistachio green hull through ME, UAE, and MAE methods were 20(v/w), 65°C, 45 minutes; 20(v/w), 65°C, 25 minutes; and 20(v/w), 65°C, 45 minutes, respectively. Under optimized conditions the experimental values well agreed with the values predicted by the proposed models.

---

Yoghurt is one of the fermented dairy products with high nutritional value and short shelf life where its shelf-life can be prolonged by drying. Therefore, in the present study, the fresh yoghurt with different amounts of dry matter (10, 20 and 28% w/w) was dehydrated by microwave–vacuum dryer at different levels of microwave powers (35, 135, and 260 W) and definite absolute pressure (125± 5 mbar). Then, the effects of type (gum tragacanth, guar gum, locust bean gum, Persian gum, and casein powder), quantity (0.25, 0.5, 0.75 and 1% w/w) in singular and combined forms (tragacanth:guar, Tragacanth:locust been gum, and guar: locust been gum), combination ratio (80:20, 50:50),and adding stage (pre/post drying) of hydroclloids over sensory and rheological properties of instant yoghurt were evaluated. Results showed that higher microwave powers and dry matter percent led to the shorter and higher drying rate, respectively. Regarding rheological properties, the storage modulus was significantly higher than loss modulus (G'>G'')  and elastic behavior was observed in majority of samples. However, sample with Guar:locust bean gums showed inverse features, also Complex viscosity and loss tangent of most samples (pre drying method) were similar to control, except one  with guar: locust been gum. Furthermore, the most accepted reconstituted yoghurt was one containing gum tragacanth, and baking powder followed by one with 0.6% tragacanth:locust bean gum (80:20, 0.6%) which were prepared with pre-drying method. Moreover, it was found that the adding stage of hydrocolloids had significant effect on the evaluated properties of instant yoghurt where pre-drying method was recognized as the most appropriate one.  

---

The effects of microwaves on physicochemical properties of corn and oat starches were investigated. Separate suspensions of corn and oat starches in distilled water  (8% w/w) were made and heated in a microwave oven at frequency of 2450 MHz and power of 360 W  for 2.5, 5, 7.5 and 10 min. Then, swelling power, solubility, relative viscosity (using U-tube viscometer), cold water viscosity  (using Rapid Visco Analyser) and textural properties (using Texture Profile Analyser) were investigated. Results showed that as the time of microwave processing increased, cold water viscosity and gel hardness decreased, however, swelling power and water solubility increased. Comparing to the conventional heating method, more reduction in the relative viscosity was observed for the microwave processed samples. In general, results showed that microwave processing had a stonger effects on structural and molecular properties of corn and oat starches than the conventional cooking. These changes may be further affect the quality of the final products.