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Yield estimation can provide critical information for high-value crop growers. It helps them to plan and coordinate the logistics of harvesting operations. Most existing yield estimation techniques are based on manual sampling and statistical approaches, which are complex, labor-intensive, and time-consuming. In recent years, advances in image processing and the ubiquitous use of autonomous platforms, such as unmanned aerial platforms, have provided an opportunity for faster and more accurate yield estimation techniques for different crops. A new rapid, efficient, and accurate image processing algorithm was proposed in this study. The image segmentation technique was able to separate mature citrus trees and natural background in CIE (Commission International Eclairage) L*a*b* (i.e., Lab) color space. The effect of camera distance to object, affected resolution, and detection accuracy were evaluated and discussed. The results showed that the distance between 1.524 meters (5 feet) and 2.134 meters (7 feet) could provide high detection accuracy. The number of correctly counted fruit reached 91.69% at the average processing time of 1.1 s per picture for 132 pictures. A correlation coefficient (R2) of 0.98 was obtained between the citrus counting algorithm and counting performed through human observation of 66 sample trees. The comparative analysis of the proposed method showed a higher accuracy rate and robustness compared to other similar studies.

Irrigation water management in tree crops requires timely and accurate determination of crop water status for making irrigation scheduling decisions. However, commonly used techniques for measuring tree water statuses, such as stem water potential measured with pressure chambers or leaf stomatal conductance measured with porometers, are manually operated and lack the timeliness for making irrigation decisions in real-time. The objective of this research was to develop and field test a new electronic sensor system capable of continuously monitoring tree trunk relative water content. Replicated sensors were installed in experimental orchards planted with pomegranate and nectarine trees. Data collected from the sensor readings were compared with periodic trunk diameter, stem water potential, and leaf stomatal conductance measurements. Strong linear correlations were observed between sensor readings and tree trunk diameter variations but with a 3–4-hour phase lag. Sensor readings were also strongly correlated to stem water potential (R2 = 0.58-0.85) and leaf stomatal conductance (R2 = 0.60-0.84) for both pomegranate and nectarine trees. The next step is to further validate the sensors in commercial orchards and apply the sensors for making real-time irrigation water management decisions.

Thermal dissipation systems are a conventional technique to estimate sap velocity by determining the temperature difference between sap flow probes. The Thermal Dissipation Probe (TDP) method is commercially available and has been used by many researchers and professionals to estimate sap flow in plants. However, some errors and practical issues cause inaccuracy when evaluating plant sap velocity with this technique. Specifically, the sources of these errors are from the effect of the ambient thermal gradient (i.e., error caused by the cold junction location), the underestimation of nighttime sap flow, and the deficient thermal contact between the probe and tree body. This article focuses on errors associated with the traditional TDP, which effect on the thermal difference between the reference and heated probes. These errors vary as a nonlinear function of the transmitter length and the numbers of cold junctions which are affected by changes in the ambient temperature. Keywords: Ambient thermal gradient, Sap velocity, Thermal dissipation probe (TDP), Thermocouple cold junction.

The shaking functionality of different types of shaking tines for citrus canopy shakers was evaluated. Shaking responses were simulated using ANSYS/LS-DYNA, and a tractor-mounted experimental shaking machine developed for conducting field trials. Straight nylon, bent nylon, straight PVC, and straight steel tines were used as shaking rods and, in experiments, accelerometers placed at branches and fruit to detect vibrational acceleration. Simulation results indicated that tine materials affected the vibrational response of trees and the acceleration peaks of branches and limbs exerted by a steel tine were ~2.0 times as high as exerted by a nylon tine. Both simulation and experimental results demonstrated that the tine bending stiffness had a positive effect on the generated acceleration. Tree injuries caused by a straight nylon tine were much less than by other tines. The results suggested that a shaking tine should have high stiffness, but its surface should be soft. These simulation and experiment methods can be used for improving canopy shaker applications. Keywords: Citrus harvest, Canopy shaking, Shaking functionality, Trial.

This study investigated the effect of ozonated air (OA) on weight loss, volume reduction (shriveling), and skin firmness on fresh figs and monitored the changes in the epidermis of OA-treated fruits within 14 d of storage at 4 °C and 65 % RH. In Phase 1 of the study, fresh Kadota figs at two different maturity levels, commercial-ripe and tree-ripe, were exposed to OA for up to 11 h at room temperature to find the optimum parameters for ozone treatment. The 3-h OA-treated (15 ppm) fig samples showed 10 % less weight loss, 16 % less shrivel, had a better appearance, showed fewer brown spots, and had less fungal growth than the control. In Phase 2, Kadota and Black Mission figs were treated with OA (15 ppm for 3 h) and their aging parameters were evaluated. The Mission figs in the control group showed the highest rate of weight loss (25.8 %) and volume reduction (32.5 %). Kadota figs had the lowest weight loss (18.8 %) and volume reduction (9.8 %) in 14 d. Due to the oxidation, the OA treatment resulted in a considerable decrease in skin firmness in both Kadota and Mission figs; however, the skin firmness increased in the Kadota samples on Day 7. The recovery of Kadota epidermises continued at a very slow rate until Day 14. However, Mission samples did not show any firmness increase on Day 7. Scanning electron microscopy showed the differences between the control and the OA-treated Kadota and Mission figs. Ozone treatment affected the epidermis of figs, specifically the stomata and epicuticular wax crystals, resulting in stomata blockage or deformation, and irregular shapes in the wax platelets. Although the fruit epidermis was affected by OA treatment, the self-assembly properties of the epicuticular wax layer helped the fruit to recover from the oxidative damage caused by ozone by Day 7. Small microcracks and cell wall disassembly were observed on the fruit surface after 14 d of cold storage; they were very noticeable in the control samples and resulted in considerable water loss and weight loss, decreased shelf life, and significant fungal infection. This study showed that OA treatment of fresh figs can be used to minimize the volume and weight loss and improve the overall quality of fresh figs.

The theory of inventive problem solving (TRIZ) is one of emerging creative problem solving methodologies. This paper proposes a way to simplify TRIZ for electrical domain usage, while making it feel less complex, more relevant and understand able for users in a specific sector. This research takes Dynamic Voltage Restorer (DVR) device as a case from electrical engineering domain, to demonstrate the proposed TRIZ based guidance framework development which will assist in solving problems of DVR devices. The proposed sector specific guidelines in particular segment of Electrical Engineering (e.g. power quality device DVR) will be closer, more comprehensible and particularly linked to key parameters of that sector. By using the derived guidance framework, field engineers with very basic TRIZ knowledge may apply TRIZ confidently for design and problem solving purpose.

The present investigation deals with the fabrication of CO2 gas sensor based on La2O3/SnO2 metal-oxide material. In this paper, the sensitive material was prepared by La2O3/SnO2 nanopowder and the addition of 1 wt.% and 3 wt.% platinum (Pt) using high-speed ball milling method. The sensitive film prepared by sensitive powder was printed on alumina (Al2O3) substrate by screen printing method. This film was characterized by X-Ray powder diffraction spectroscopy, and Field-emission scanning electron microscopy. As a result, the prepared 3 wt.% Pt/La2O3/SnO2 thick film sensitive paste exhibits a high sensitivity to increasing the CO2 gas concentration at 225 °C in air atmosphere.

Global warming, depletion of natural resources, acid rains, air and water pollutions, and ozone depletions are some of the environmental consequences that are deemed attributable to human activities on planet earth. Sustainable practices have been therefore evolved as main remedies to tackles these issues. Green roof strategy is one of these practices that not only provides heat island amelioration and thermal comfort for occupants but also reduces energy consumption of buildings as well as add aesthetic values to the environment. This paper targets to run a review on the application of green roof strategy. The review scans a time frame from 2002 through early 2012 with a focus on energy related topics on energy related topics of green roofs. The review discussed various types of green roofs, components of a green roof, economic revenues, and technical attributes. Many general advantages and few general disadvantages of green roofs in one hand and pros and cons of green roofs with respect to energy utilization on the other hand are also synthesized. Some recommendations for future study are also proposed.

Second and third-order passive filters (LC and LCL) are interesting filters used for grid-connected inverters. Due to the stability problems of this filter regarding resonance frequency, additional damping resistor suggested for an LCL filter. However, the resistor value has a considerable impact on the response of the filter, voltage and current harmonic distortion and system power loss. In this paper, the mathematic characteristics of LC, LCL filter, parallel and series connected damping LCL filters will be described with their design for 3-phase PV grid-connected inverter. In this study optimal values used to meet IEEE 519-1992 standard limits for total harmonic distortion. Simulation is used to validate the theoretical analysis of filters, filters' stability and power quality at grid-connected point.

The time-domain behavior of the n2+n voltage multiplier was unknown. Therefore, suggesting an approximate mathematical model for the output voltage of this circuit was necessary. This manuscript presents an optimized approximate mathematical model for the output voltage of a n2+n voltage multiplier. The suggested mathematical model includes two components of an exponential recovery equation and a sinusoidal equation which are performing as a function of time and frequency.

Sensors, work on the entrance gate for exploring dynamic environments and system response. The sensor behavior plays an important role in system modeling. Therefore, finding the mathematical model, which can describe the sensor response with maximum information over time in different environments and situations, is necessary. This paper, attempts to model the optimal transfer function of the SnO2 type gas sensor (TGS 813) for transient response and steady-state zones, based on the acquired data of the sensor. The model could be used to obtain the mathematical equation for the response, as a transfer function based on different concentrations, for the specific temperature and humidly. The data analysis has been done with Matlab software, and Genetic algorithm is further used to optimize the transfer function parameters. Moreover, the effect of variation in concentration on the transfer function coefficients has been explored. The results show that the modeling can be helpful for sensor response behavior simulation as well as physical and chemical reaction investigation.

Visualization of the energy equation can simplify understanding the performance of a Marx pulse generator. In this paper, the energy of a Marx pulse generator is calculated and visualized for input dc voltage from 1 to 20 kV, value of the capacitor from 1 to 33 nF and the number of stages from 1 to 20 stages. Moreover, in order to calculate the approximate cost of the Marx pulse generator, an equation proposed and evaluated.

The necessitation in the optimal power demand model, make it an impetus to present this work as a glaring path in determining the optimum power demand curve, using the available data of a substation. The data are used to find the equation and its coefficients of determination that can give the best-fit curve of the power demand of a substation, based on the available data. This will produce a model that can be validated by comparing the data and figured out the equation.

Heating is an important step in food processing. A new method of heating uses the natural electrical resistance of the food to generate heat. In this method electrical energy is transformed into thermal energy. This kind of food heating processing operation is called ohmic heating. The rate of ohmic heating critically depends on the Electrical Conductivity of the food during the process. Reviewing a number of researches shows that the usage of direct current for ohmic heating process causes electrolyze in liquid beverages. Moreover, usage of alternating current eliminates the probability of adverse electrochemical reaction. In addition, when the frequency increases, the risk of oxidation in electrodes will decrease. In this regard, for heating different kinds and sizes of food, it is necessary to have an electrical power source with variable output voltage and frequency. This research attempts to design and simulate the variable voltage and frequency electrical power source to feed a 10 kW ohmic heating process at high frequency (10 kHz). The ohmic heating load is simulated by three-phase resistive load. According to Joulepsilas first law, the temperature in heat generation process is closely related to electrical power and time of process. Hence, in this simulation, the value of temperature is controlled by value of power that is generated by current which flows through resistive load with control of the time period and the duty cycle. Furthermore, one of the most important things to have an effective ohmic heating process is supplying the continuous current during the process. The result of this study indicated a simple method to supply a continual current for load during the ohmic heating process.