Improving Fruit Quality in ‘Hayward’ Kiwifruit Using Proper Leaf to Fruit Ratios and Girdling

Pedram Assar,Saeid Eshghi,Enayatollah Tafazoli,Majid Rahemi,Yazdan Gholi Khazaeipoul,Abbas Saboorrooh Monfared 한국원예학회 2009 Horticulture, Environment, and Biotechnology Vol.50 No.6

The effects of different leaf to fruit ratios, summer pruning time, and girdling on quantitative and qualitative characteristics of ‘Hayward’ kiwifruit were examined. On each vine, four uniform canes were selected and by pruning their fruiting laterals, leaf to fruit ratio was adjusted and maintained at 1:1, 2:1, 3:1, or 4:1. In control treatment, these selected canes were left intact without topping and removing any lateral growth. Half of the selected canes were girdled by removing a 5 mm strip of bark around the base of each cane, while the other half were left intact. Leaf to fruit adjustment and girdling were imposed 2 weeks after petal fall. To show how pruning time can affect fruit characteristics of the four mentioned selected canes, other canes and their laterals in each vine were pruned early (similar to selected canes) or late (in late summer) (vine general pruning methods A and B, respectively). In both methods, pruning manner was in accordance with common practice in Persian commercial orchards (heading cuts were performed after 3-4 leaves distal to the latest fruit). Finally, fruits of selected canes were harvested and analyzed. Results indicated the necessity of summer pruning performance to obtain fruits with higher quality. The importance of total leaf numbers of laterals in each cane as carbohydrate suppliers for fruits in order to support potential fruit growth was proved. Also, dependence of fruit growth in each cane on carbohydrate supply of other canes was detected. In pruned vines in method A (early summer pruned and as a result having light canopies with optimum light penetration) on girdled experimental canes, minimum leaf to fruit ratio that was required to achieve significant changes in fruit quantitative characteristics compared with control, was 1:1 for width and weight and 2:1 for length and volume. The positive effect of girdling on fruit quantitative characteristics via improving the available photosynthates supply to developing fruits was confirmed. Smaller responses of fruit growth to increasing the leaf to fruit ratios on non-girdled canes due to competition for photosynthate from other sinks, was observed. In pruned vines in method A (better canopy conditions), girdling performance combined with 3:1 and 4:1 leaf to fruit ratios resulted in higher vitamin C and total soluble solids contents, respectively. The positive effect of on time (early) summer pruning on fruit characteristics was proved.

Molecular Dynamics (MD) Simulation of Zwitterion-Functionalized PMMA with Hydrophilic and Antifouling Surface Characteristics

Pedram Vousoughi,Mohammad Reza Moghbeli,Sousa Javan Nikkhah 한국고분자학회 2019 Macromolecular Research Vol.27 No.12

In this study, the effect of surface functionalization of poly (methyl methacrylate) (PMMA) layer using [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide, a zwitterion comonomer, on PMMA’s hydrophilicity and antifouling properties was investigated via the utilization of a molecular dynamics (MD) simulation. The modified layers were composed of PMMA chains with 30 repeating units, which were surface functionalized using various amount of zwitterionic comonomers, i.e. 0, 6.66, 9.99 and 16.65 wt%. In this case, the hydrophobicity of the resultant layer was evaluated calculating the contact angle values. Additionally, the calculated contact angles using water and diiodomethane over the PMMA model were compared to experimental values to validate the simulation procedure. To investigate the antifouling property, both the top and bottom models faces were contacted to a given feed composed of a water/ hydrocarbon mixed solvent ratio, 60/40 (vol/vol). Likewise, the number density and radial distribution function (RDF) were determined to investigate the change in the solvent molecules repulsion or organic antifouling property of the layer surface, along with increasing the content of the functionalizing groups.

Impact of Metal Thickness and Field Shaper on the Time-varying Processes during Impulse Electromagnetic Forming in Tubular Geometries

Pedram Gharghabi,Peyman Dordizadeh B.,Kaveh Niayesh 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.61

Impulse electromagnetic forming is an effective and powerful technique widely used for reshaping or joining metallic sheets and tubes. This technique can be employed for different purposes; however the main principle in all of the applications of this technique is the same. During the last decades, engineers especially in automotive industry are attracted in forming the lightweight and low ductile sheet or tubular metals. In this method a work coil is located inside or outside of the tubular work-piece. By discharging a pulsed capacitor through a fast acting switch an intense current passes through the coil and due to the highly time varying magnetic field, current is induced in the work-piece and consequently excessive force is applied to the metallic tube. Depending on the location of the coil, inside or outside of the tubular work-piece, the resultant force would cause the work-piece to expand or contract. The overall performance of the system is considerably influenced by the thickness and material properties of the work-piece as well as by the geometrical parameters of the field-shaper. In this paper, simulations based on finite element method (FEM) are used to study the impulse electromagnetic forming (EMF) process. By changing the geometry and the configuration of the system, the impact of the different influential parameters like thickness of the work-piece and field-shaper geometry on the performance of the whole system have been studied. It must be noted that because of deformation of the work-piece, the electrical parameters of the system like mutual inductance are time dependent. To be able to take these time-variant effects into account, the stress and strain rates caused by exerted force for different positions of work coil and the resultant deformation of the work-piece have been calculated in each time step. Using magnetic field measurements applied on an experimental set-up, the simulation results are verified and some simple guidelines to design the impulse EMF systems for tubular geometries have been derived.

Optimization of Mass-spring Model Parameters by ICA for Assessing Compressional Behavior of Warp-knitted Spacer Fabrics Reinforced Polyurethane Cast Elastomer Composites

Pedram Payvandy,Mohammad Saleh Ahmadi,Masih Yousefpour 한국섬유공학회 2022 Fibers and polymers Vol.23 No.12

Warp knitted spacer fabrics (WKSFs) have been developed for many applications such as cushioning materials. Therefore, the study on the compressional behavior of WKSFs and their composites is of great importance. In this study, sixtypes of mass-spring models, i.e. Maxwell, Kelvin, Standard linear, Burger, linear spring, and non-linear spring are used toestimate compressional behavior of WKSF reinforced polyurethane cast elastomer composites under flat and spherical typesof loading. Imperialist Competitive Algorithm (ICA) is utilized to predict models’ parameters for minimizing the differencesbetween experimental and theoretical data. The best results were obtained by the non-linear spring model with the mean errorof 4.12 % and 3.37 % for flat and spherical compression, respectively. The mean of errors of the other models were higherthan 14.75 %. It is proved that the compression force-displacement curves of the samples in both flat and spherical loadingfollow exponential forms.

Challenges in Selecting an Appropriate Heat Stress Index to Protect Workers in Hot and Humid Underground Mines

Pedram Roghanchi,Karoly C. Kocsis 한국산업안전보건공단 산업안전보건연구원 2018 Safety and health at work Vol.9 No.1

Background: A detailed evaluation of the underground mine climate requires extensive measurements to be performed coupled to climatic modeling work. This can be labor-intensive and time-consuming, and consequently impractical for daily work comfort assessments. Therefore, a simple indicator like a heat stress index is needed to enable a quick, valid, and acceptable evaluation of underground climatic conditions on a regular basis. This can be explained by the unending quest to develop a “universal index,” which has led to the proliferation of many proposed heat stress indices. Methods: The aim of this research study is to discuss the challenges in identifying and selecting an appropriate heat stress index for thermal planning and management purposes in underground mines. A method is proposed coupled to a defined strategy for selecting and recommending heat stress indices to be used in underground metal mines in the United States and worldwide based on a thermal comfort model. Results: The performance of current heat stress indices used in underground mines varies based on the climatic conditions and the level of activities. Therefore, carefully selecting or establishing an appropriate heat stress index is of paramount importance to ensure the safety, health, and increasing productivity of the underground workers. Conclusion: This method presents an important tool to assess and select the most appropriate index for certain climatic conditions to protect the underground workers from heat-related illnesses. Although complex, the method presents results that are easy to interpret and understand than any of the currently available evaluation methods.

The effect of welding on the strength of aluminium stiffened plates subject to combined uniaxial compression and lateral pressure

Pedram, Masoud,Khedmati, Mohammad Reza The Society of Naval Architects of Korea 2014 International Journal of Naval Architecture and Oc Vol.6 No.1

Nowadays aluminum stiffened plates are one of the major constituents of the marine structures, especially high-speed vessels. On one hand, these structures are subject to various forms of loading in the harsh sea environment, like hydrostatic lateral pressures and in-plane compression. On the other hand, fusion welding is often used to assemble those panels. The common marine aluminum alloys in the both 5,000 and 6,000 series, however, lose a remarkable portion of their load carrying capacity due to welding. This paper presents the results of sophisticated finite-element investigations considering both geometrical and mechanical imperfections. The tested models were those proposed by the ultimate strength committee of $15^{th}$ ISSC. The presented data illuminates the effects of welding on the strength of aluminum plates under above-mentioned load conditions.

Current understanding of cancer-intrinsic PD-L1: regulation of expression and its protumoral activity

( Pedram Yadollahi ),( You-kyoung Jeon ),( Wooi Loon Ng ),( Inhak Choi ) 생화학분자생물학회(구 한국생화학분자생물학회) 2021 BMB Reports Vol.54 No.1

In the last decade, we have witnessed an unprecedented clinical success in cancer immunotherapies targeting the programmed cell-death ligand 1 (PD-L1) and programmed cell-death 1 (PD-1) pathway. Besides the fact that PD-L1 plays a key role in immune regulation in tumor microenvironment, recently a plethora of reports has suggested a new perspective of non-immunological functions of PD-L1 in the regulation of cancer intrinsic activities including mesenchymal transition, glucose and lipid metabolism, stemness, and autophagy. Here we review the current understanding on the regulation of expression and intrinsic protumoral activity of cancer-intrinsic PD-L1. [BMB Reports 2021; 54(1): 12-20]

Melanoma and atypical melanocytic tumors in pediatric population

( Pedram Gerami ) 대한피부과학회 2023 대한피부과학회 학술발표대회집 Vol.74 No.2

Pitting Corrosion Behavior of CUSTOM 450 Stainless Steel Using Electrochemical Characterization

Omid Pedram,Yousef Mollapour,Hassan Shayani‑jam,Esmaeil Poursaeidi,Ramin Khamedi 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11

In this study, the electrochemical polarization tests were performed on tensioned and non-tensioned CUSTOM 450 specimensin a 3.5 wt% NaCl solution to investigate pitting potential and stable pit initiation time. A potentiodynamic test wasconducted to determine the exact amount of pitting potentials. According to the potentiostatic tests, a relation between appliedpotential and the stable pit initiation time was obtained. Concerning this relation, stable pitting time can be predicted withoutexperimental works. Optical microscopy was used to evaluate the shape of the pits. Tensile stress led the pit to experiencethe “pit to crack” step. The corrosion rate of samples was studied by the determination of mass loss. Mass loss measurementsand current density–time curve in potentiostatic tests demonstrated the rate of pitting corrosion decreased as time passed. Finally, the depth of the pits was measured by the eddy current technique. The results showed that tensile stress facilitateddeeper pit development.

Challenges in Selecting an Appropriate Heat Stress Index to Protect Workers in Hot and Humid Underground Mines

Roghanchi, Pedram,Kocsis, Karoly C. Occupational Safety and Health Research Institute 2018 Safety and health at work Vol.9 No.1

Background: A detailed evaluation of the underground mine climate requires extensive measurements to be performed coupled to climatic modeling work. This can be labor-intensive and time-consuming, and consequently impractical for daily work comfort assessments. Therefore, a simple indicator like a heat stress index is needed to enable a quick, valid, and acceptable evaluation of underground climatic conditions on a regular basis. This can be explained by the unending quest to develop a "universal index," which has led to the proliferation of many proposed heat stress indices. Methods: The aim of this research study is to discuss the challenges in identifying and selecting an appropriate heat stress index for thermal planning and management purposes in underground mines. A method is proposed coupled to a defined strategy for selecting and recommending heat stress indices to be used in underground metal mines in the United States and worldwide based on a thermal comfort model. Results: The performance of current heat stress indices used in underground mines varies based on the climatic conditions and the level of activities. Therefore, carefully selecting or establishing an appropriate heat stress index is of paramount importance to ensure the safety, health, and increasing productivity of the underground workers. Conclusion: This method presents an important tool to assess and select the most appropriate index for certain climatic conditions to protect the underground workers from heat-related illnesses. Although complex, the method presents results that are easy to interpret and understand than any of the currently available evaluation methods.