Search results for: Reyhane Hamed Kamran

Authors: Hamed Jafargholi

Abstract:

Global warming presents an immense environmental risk, causing detrimental impacts on ecological systems and putting coastal areas at risk. Implementing efficient measures to minimize greenhouse gas emissions and the use of fossil fuels is essential to reducing global warming. Vapor compression heat pumps provide a practical method for harnessing energy from waste heat sources and reducing energy consumption. However, traditional working fluids used in these heat pumps generally contain a significant global warming potential (GWP), which might cause severe greenhouse effects if they are released. The goal of the emphasis on low-GWP (below 150) refrigerants is to further the vapor compression heat pumps. A classification system for vapor compression heat pumps is offered, with different boundaries based on the needed heat temperature and advancements in heat pump technology. A heat pump could be classified as a low temperature heat pump (LTHP), medium temperature heat pump (MTHP), high temperature heat pump (HTHP), or ultra-high temperature heat pump (UHTHP). The HTHP/UHTHP border is 160 °C, the MTHP/HTHP and LTHP/MTHP limits are 100 and 60 °C, respectively. The refrigerant is one of the most important parts of a vapor compression heat pump system. Presently, the main ways to choose a refrigerant are based on ozone depletion potential (ODP) and GWP, with GWP being the lowest possible value and ODP being zero. Pure low-GWP refrigerants, such as natural refrigerants (R718 and R744), hydrocarbons (R290, R600), hydrofluorocarbons (R152a and R161), hydrofluoroolefins (R1234yf, R1234ze(E)), and hydrochlorofluoroolefin (R1233zd(E)), were selected as candidates for vapor compression heat pump systems based on these selection principles. The performance, characteristics, and potential uses of these low-GWP refrigerants in heat pump systems are investigated in this paper. As vapor compression heat pumps with pure low-GWP refrigerants become more common, more and more low-grade heat can be recovered. This means that energy consumption would decrease. The research outputs showed that the refrigerants R718 for UHTHP application, R1233zd(E) for HTHP application, R600, R152a, R161, R1234ze(E) for MTHP, and R744, R290, and R1234yf for LTHP application are appropriate. The selection of an appropriate refrigerant should, in fact, take into consideration two different environmental and thermodynamic points of view. It might be argued that, depending on the situation, a trade-off between these two groups should constantly be considered. The environmental approach is now far stronger than it was previously, according to the European Union regulations. This will promote sustainable energy consumption and social development in addition to assisting in the reduction of greenhouse gas emissions and the management of global warming.

Keywords: vapor compression, global warming potential, heat pumps, greenhouse

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Authors: Domenico Panno, Antonino D’amico, Hamed Jafargholi

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This paper presents an experimental analysis of the performance of a system for freezing fish products equipped with a modulating vapour injection scroll compressor operating with R448A refrigerant. Freezing is a critical process for the preservation of seafood products, as it influences quality, food safety, and environmental sustainability. The use of a modulating scroll compressor with vapour injection, associated with the R448A refrigerant, is proposed as a solution to optimize the performance of the system, reducing energy consumption and mitigating the environmental impact. The stream injection modulating scroll compressor represents an advanced technology that allows you to adjust the compressor capacity based on the actual cooling needs of the system. Vapour injection allows the optimization of the refrigeration cycle, reducing the evaporation temperature and improving the overall efficiency of the system. The use of R448A refrigerant, with a low Global Warming Potential (GWP), is part of an environmental sustainability perspective, helping to reduce the climate impact of the system. The aim of this research was to evaluate the performance of the system through a series of experiments conducted on a pilot plant for the freezing of fish products. Several operational variables were monitored and recorded, including evaporation temperature, condensation temperature, energy consumption, and freezing time of seafood products. The results of the experimental analysis highlighted the benefits deriving from the use of the modulating vapour injection scroll compressor with the R448A refrigerant. In particular, a significant reduction in energy consumption was recorded compared to conventional systems. The modulating capacity of the compressor made it possible to adapt the cold production to variations in the thermal load, ensuring optimal operation of the system and reducing energy waste. Furthermore, the use of an electronic expansion valve highlighted greater precision in the control of the evaporation temperature, with minimal deviation from the desired set point. This helped ensure better quality of the final product, reducing the risk of damage due to temperature changes and ensuring uniform freezing of the fish products. The freezing time of seafood has been significantly reduced thanks to the configuration of the entire system, allowing for faster production and greater production capacity of the plant. In conclusion, the use of a modulating vapour injection scroll compressor operating with R448A has proven effective in improving the performance of a system for freezing fish products. This technology offers an optimal balance between energy efficiency, temperature control, and environmental sustainability, making it an advantageous choice for food industries.

Keywords: scroll compressor, vapor injection, refrigeration system, EER

Procedia PDF Downloads 45

Authors: Muhammad Haris, Syed Kamran Ali, Mubeen Islam, Tariq Mehmood, Faisal Shah

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Jacobabad Khairpur High, part of a Sukkur rift zone, is the separating boundary between Central and Southern Indus Basin, formed as a result of Post-Jurassic uplift after the deposition of Middle Jurassic Chiltan Formation. Habib Rahi Formation of Middle to Late Eocene outcrops in the vicinity of Jacobabad Khairpur High, a section at Rohri near Sukkur is measured in detail for lithofacies, microfacies, diagenetic analysis and sequence stratigraphy. Habib Rahi Formation is richly fossiliferous and consists of mostly limestone with subordinate clays and marl. The total thickness of the formation in this section is 28.8m. The bottom of the formation is not exposed, while the upper contact with the Sirki Shale of the Middle Eocene age is unconformable in some places. A section is measured using Jacob’s Staff method, and traverses were made perpendicular to the strike. Four different lithofacies were identified based on outcrop geology which includes coarse-grained limestone facies (HR-1 to HR-5), massive bedded limestone facies (HR-6 HR-7), and micritic limestone facies (HR-8 to HR-13) and algal dolomitic limestone facie (HR-14). Total 14 rock samples were collected from outcrop for detailed petrographic studies, and thin sections of respective samples were prepared and analyzed under the microscope. On the basis of Dunham’s (1962) classification systems after studying textures, grain size, and fossil content and using Folk’s (1959) classification system after reviewing Allochems type, four microfacies were identified. These microfacies include HR-MF 1: Benthonic Foraminiferal Wackstone/Biomicrite Microfacies, HR-MF 2: Foramineral Nummulites Wackstone-Packstone/Biomicrite Microfacies HR-MF 3: Benthonic Foraminiferal Packstone/Biomicrite Microfacies, HR-MF 4: Bioclasts Carbonate Mudstone/Micrite Microfacies. The abundance of larger benthic Foraminifera’s (LBF), including Assilina sp., A. spiral abrade, A. granulosa, A. dandotica, A. laminosa, Nummulite sp., N. fabiani, N. stratus, N. globulus, Textularia, Bioclasts, and Red algae indicates shallow marine (Tidal Flat) environment of deposition. Based on variations in rock types, grain size, and marina fauna Habib Rahi Formation shows progradational stacking patterns, which indicates coarsening upward cycles. The second order of sea-level rise is identified (spanning from Y-Persian to Bartonian age) that represents the Transgressive System Tract (TST) and a third-order Regressive System Tract (RST) (spanning from Bartonian to Priabonian age). Diagenetic processes include fossils replacement by mud, dolomitization, pressure dissolution associated stylolites features and filling with dark organic matter. The presence of the microfossils includes Nummulite. striatus, N. fabiani, and Assilina. dandotica, signify Bartonian to Priabonian age of Habib Rahi Formation.

Keywords: Jacobabad Khairpur High, Habib Rahi Formation, lithofacies, microfacies, sequence stratigraphy, diagenetic history

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Authors: Seyed Hamed Mousavi, Juha M. Hijmans, Reza Rajabi, Ron Diercks, Johannes Zwerver, Henk van der Worp

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Introduction: Running is one of the most popular sports activity among people. Improper sagittal plane ankle, knee and hip kinematics are considered to be associated with the increase of injury risk in runners. Motion assessing smart-phone applications are increasingly used to measure kinematics both in the field and laboratory setting, as they are cheaper, more portable, accessible, and easier to use relative to 3D motion analysis system. The aims of this study are 1) to compare the results of 3D gait analysis system and CE; 2) to evaluate the test-retest and intra-rater reliability of coach’s eye (CE) app for the sagittal plane hip, knee, and ankle angles in the touchdown and toe-off while running. Method: Twenty subjects participated in this study. Sixteen reflective markers and cluster markers were attached to the subject’s body. Subjects were asked to run at a self-selected speed on a treadmill. Twenty-five seconds of running were collected for analyzing kinematics of interest. To measure sagittal plane hip, knee and ankle joint angles at touchdown (TD) and toe off (TO), the mean of first ten acceptable consecutive strides was calculated for each angle. A smartphone (Samsung Note5, android) was placed on the right side of the subject so that whole body was simultaneously filmed with 3D gait system during running. All subjects repeated the task with the same running speed after a short interval of 5 minutes in between. The CE app, installed on the smartphone, was used to measure the sagittal plane hip, knee and ankle joint angles at touchdown and toe off the stance phase. Results: Intraclass correlation coefficient (ICC) was used to assess test-retest and intra-rater reliability. To analyze the agreement between 3D and 2D outcomes, the Bland and Altman plot was used. The values of ICC were for Ankle at TD (TRR=0.8,IRR=0.94), ankle at TO (TRR=0.9,IRR=0.97), knee at TD (TRR=0.78,IRR=0.98), knee at TO (TRR=0.9,IRR=0.96), hip at TD (TRR=0.75,IRR=0.97), hip at TO (TRR=0.87,IRR=0.98). The Bland and Altman plots displaying a mean difference (MD) and ±2 standard deviation of MD (2SDMD) of 3D and 2D outcomes were for Ankle at TD (MD=3.71,+2SDMD=8.19, -2SDMD=-0.77), ankle at TO (MD=-1.27, +2SDMD=6.22, -2SDMD=-8.76), knee at TD (MD=1.48, +2SDMD=8.21, -2SDMD=-5.25), knee at TO (MD=-6.63, +2SDMD=3.94, -2SDMD=-17.19), hip at TD (MD=1.51, +2SDMD=9.05, -2SDMD=-6.03), hip at TO (MD=-0.18, +2SDMD=12.22, -2SDMD=-12.59). Discussion: The ability that the measurements are accurately reproduced is valuable in the performance and clinical assessment of outcomes of joint angles. The results of this study showed that the intra-rater and test-retest reliability of CE app for all kinematics measured are excellent (ICC ≥ 0.75). The Bland and Altman plots display that there are high differences of values for ankle at TD and knee at TO. Measuring ankle at TD by 2D gait analysis depends on the plane of movement. Since ankle at TD mostly occurs in the none-sagittal plane, the measurements can be different as foot progression angle at TD increases during running. The difference in values of the knee at TD can depend on how 3D and the rater detect the TO during the stance phase of running.

Keywords: reliability, running, sagittal plane, two dimensional

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Authors: P. Naderi, M. N. Ouarzazi, S. C. Hirata, H. Ben Hamed, H. Beji

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The stability of mixed convection in a Newtonian fluid medium heated from below and cooled from above, also known as the Poiseuille-Rayleigh-Bénard problem, has been extensively investigated in the past decades. To our knowledge, mixed convection in porous media has received much less attention in the published literature. The present paper extends the mixed convection problem in porous media for the case of a viscoelastic fluid flow owing to its numerous environmental and industrial applications such as the extrusion of polymer fluids, solidification of liquid crystals, suspension solutions and petroleum activities. Without a superimposed through-flow, the natural convection problem of a viscoelastic fluid in a saturated porous medium has already been treated. The effects of the viscoelastic properties of the fluid on the linear and nonlinear dynamics of the thermoconvective instabilities have also been treated in this work. Consequently, the elasticity of the fluid can lead either to a Hopf bifurcation, giving rise to oscillatory structures in the strongly elastic regime, or to a stationary bifurcation in the weakly elastic regime. The objective of this work is to examine the influence of the main horizontal flow on the linear and characteristics of these two types of instabilities. Under the Boussinesq approximation and Darcy's law extended to a viscoelastic fluid, a temporal stability approach shows that the conditions for the appearance of longitudinal rolls are identical to those found in the absence of through-flow. For the general three-dimensional (3D) perturbations, a Squire transformation allows the deduction of the complex frequencies associated with the 3D problem using those obtained by solving the two-dimensional one. The numerical resolution of the eigenvalue problem concludes that the through-flow has a destabilizing effect and selects a convective configuration organized in purely transversal rolls which oscillate in time and propagate in the direction of the main flow. In addition, by using the mathematical formalism of absolute and convective instabilities, we study the nature of unstable three-dimensional disturbances. It is shown that for a non-vanishing through-flow, general three-dimensional instabilities are convectively unstable which means that in the absence of a continuous noise source these instabilities are drifted outside the porous medium, and no long-term pattern is observed. In contrast, purely transversal rolls may exhibit a transition to absolute instability regime and therefore affect the porous medium everywhere including in the absence of a noise source. The absolute instability threshold, the frequency and the wave number associated with purely transversal rolls are determined as a function of the Péclet number and the viscoelastic parameters. Results are discussed and compared to those obtained from laboratory experiments in the case of Newtonian fluids.

Keywords: instability, mixed convection, porous media, and viscoelastic fluid

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Authors: Hamdan Hamood Aldumaini, Amjad Hussein Meqdam, Shamsaldeen kassim Ali, Hamed Mohammed Al-Yousefi, Haron Ahmed Al-Badawi

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Background: Autism Spectrum Disorder (ASD) is a complex developmental challenge characterized by significant impairments in social interaction, communication, and behavioral patterns. Diagnosing ASD is challenging due to the lack of definitive medical tests, making early identification crucial. Therefore, increasing people's awareness about autism leads to early diagnosis and better prognosis. Objective: Our study aims to identify the initial symptoms prompting families to seek medical advice, determine the timeline between symptom onset and formal diagnosis, and explore methods for assessing the severity of ASD. Subjects and Methods: The study design employed was a descriptive cross-sectional design, which was suitable for the nature of the research. The data collection took place from March 5, 2022, to April 5, 2022, in Autism Rehabilitation Centers in Sana'a, Yemen. The study population consisted of all children who were diagnosed with autism and visited Autism rehabilitation centers in Sana'a city. The sample size was determined using Epi info version 7, and a total population of 587 autistic children attending the treatment was calculated, but only 250 children were included in this study (176 were male vs. 74 female). Result: In terms of sociability problems, it was found that a significant proportion of Yemeni children with autism experienced difficulties in this area. Specifically, 39.6% were classified as having severe sociability problems, while 28.4% were classified as having moderate issues. Sensory-cognitive awareness problems were also prevalent among the respondents, with 29.6% exhibiting severe difficulties in this domain. Health and physical problems were identified as significant concerns for Yemeni children with autism. The results indicated that 38.4% of the participants experienced severe health and physical issues. Identifying the first symptoms of autism is crucial for early detection and intervention. According to the study, speech delay was the most commonly observed first abnormality, reported by 71.3% of parents. Communication difficulties with others were the second most noticed abnormality, reported by 54.9% of parents. Repetitive movements were the third most commonly observed abnormality, reported by 18% of parents. Regarding the awareness among parents of ASD, our study showed that a significant portion (62%) of parents lack awareness about Autism Spectrum Disorder (ASD) and its causes. Surprisingly, a majority of these parents (over 80%) believe that autism is a curable condition. Additionally, more than half (51.2%) of the parents surveyed reported insufficient knowledge about medication options available to support therapy and rehabilitation for their autistic children.

Keywords: autism characteristics, rehabilitation centres, yemen, children

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Authors: Hamed Khosravi, Reza Eslami-Farsani

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Increased interest in lightweight and efficient structural components has created the need for selecting materials with improved mechanical properties. To do so, composite materials are being widely used in many applications, due to durability, high strength and modulus, and low weight. Among the various composite structures, grid-stiffened structures are extensively considered in various aerospace and aircraft applications, because of higher specific strength and stiffness, higher impact resistance, superior load-bearing capacity, easy to repair, and excellent energy absorption capability. Although there are a good number of publications on the design aspects and fabrication of grid structures, little systematic work has been reported on their material modification to improve their properties, to our knowledge. Therefore, the aim of this research is to study the reinforcing effect of silica nanoparticles on the flexural properties of epoxy/E-glass isogrid panels under three-point bending test. Samples containing 0, 1, 3, and 5 wt.% of the silica nanoparticles, with 44 and 48 vol.% of the glass fibers in the ribs and skin components respectively, were fabricated by using a manual filament winding method. Ultrasonic and mechanical routes were employed to disperse the nanoparticles within the epoxy resin. To fabricate the ribs, the unidirectional fiber rovings were impregnated with the matrix mixture (epoxy + nanoparticles) and then laid up into the grooves of a silicone mold layer-by-layer. At once, four plies of woven fabrics, after impregnating into the same matrix mixture, were layered on the top of the ribs to produce the skin part. In order to conduct the ultimate curing and to achieve the maximum strength, the samples were tested after 7 days of holding at room temperature. According to load-displacement graphs, the bellow trend was observed for all of the samples when loaded from the skin side; following an initial linear region and reaching a load peak, the curve was abruptly dropped and then showed a typical absorbed energy region. It would be worth mentioning that in these structures, a considerable energy absorption was observed after the primary failure related to the load peak. The results showed that the flexural properties of the nanocomposite samples were always higher than those of the nanoparticle-free sample. The maximum enhancement in flexural maximum load and energy absorption was found to be for the incorporation of 3 wt.% of the nanoparticles. Furthermore, the flexural stiffness was continually increased by increasing the silica loading. In conclusion, this study suggested that the addition of nanoparticles is a promising method to improve the flexural properties of grid-stiffened fibrous composite structures.

Keywords: grid-stiffened composite structures, nanocomposite, three point flexural test , energy absorption

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Authors: Hamed Yaghoubi, Esmaeil Salahi, Fateme Taati

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The effective shear and bulk viscosity, as well as dynamic viscosity, describe the rheological properties of the ceramic body during the liquid phase sintering process. The rheological parameters depend on the physical and thermomechanical characteristics of the material such as relative density, temperature, grain size, and diffusion coefficient and activation energy. The main goal of this research is to acquire a comprehensive understanding of the response of an incompressible viscose ceramic material during liquid phase sintering process such as stress-strain relations, sintering and hydrostatic stress, the prediction of anisotropic shrinkage and heterogeneous densification as a function of sintering time by including the simultaneous influence of gravity field, and frictional force. After raw materials analysis, the standard hard porcelain mixture as a ceramic body was designed and prepared. Three different experimental configurations were designed including midpoint deflection, sinter bending, and free sintering samples. The numerical method for the ceramic specimens during the liquid phase sintering process are implemented in the CREEP user subroutine code in ABAQUS. The numerical-experimental procedure shows the anisotropic behavior, the complete difference in spatial displacement through three directions, the incompressibility for ceramic samples during the sintering process. The anisotropic shrinkage factor has been proposed to investigate the shrinkage anisotropy. It has been shown that the shrinkage along the normal axis of casting sample is about 1.5 times larger than that of casting direction, the gravitational force in pyroplastic deformation intensifies the shrinkage anisotropy more than the free sintering sample. The lowest and greatest equivalent creep strain occurs at the intermediate zone and around the central line of the midpoint distorted sample, respectively. In the sinter bending test sample, the equivalent creep strain approaches to the maximum near the contact area with refractory support. The inhomogeneity in Von-Misses, pressure, and principal stress intensifies the relative density non-uniformity in all samples, except in free sintering one. The symmetrical distribution of stress around the center of free sintering sample, cause to hinder the pyroplastic deformations. Densification results confirmed that the effective bulk viscosity was well-defined with relative density values. The stress analysis confirmed that the sintering stress is more than the hydrostatic stress from start to end of sintering time so, from both theoretically and experimentally point of view, the sintering process occurs completely.

Keywords: anisotropic shrinkage, ceramic material, liquid phase sintering process, rheological properties, numerical-experimental procedure

Procedia PDF Downloads 341

Authors: Andrew White, Abigail Lowe, Kory Watkins, Hamed Akhlaghi, Nicole Winter

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The timing and appropriateness of diagnostic imaging are critical to the evaluation and management of traumatic injuries. Within the subclass of trauma patients, the prevalence of c-spine injury is less than 4%. However, the incidence of delayed diagnosis within this cohort has been documented as up to 20%, with inadequate radiological examination most cited issue. In order to assess those in which c-spine injury cannot be fully excluded based on clinical examination alone and, therefore, should undergo diagnostic imaging, a set of criteria is used to provide clinical guidance. The NEXUS (National Emergency X-Radiography Utilisation Study) criteria is a validated clinical decision-making tool used to facilitate selective c-spine radiography. The criteria allow clinicians to determine whether cervical spine imaging can be safely avoided in appropriate patients. The NEXUS criteria are widely used within the Emergency Department setting given their ease of use and relatively straightforward application and are used in the Victorian State Trauma System’s guidelines. This audit utilized retrospective data collection to examine the concordance of c-spine imaging in trauma patients to that of the NEXUS criteria and assess compliance with state guidance on diagnostic imaging in trauma. Of the 183 patients that presented with trauma to the head, neck, or face (244 excluded due to incorrect triage), 98 did not undergo imaging of the c-spine. Out of those 98, 44% fulfilled at least one of the NEXUS criteria, meaning the c-spine could not be clinically cleared as per the current guidelines. The criterion most met was intoxication, comprising 42% (18 of 43), with midline spinal tenderness (or absence of documentation of this) the second most common with 23% (10 of 43). Intoxication being the most met criteria is significant but not unexpected given the cohort of patients seen at St Vincent’s and within many emergency departments in general. Given these patients will always meet NEXUS criteria, an element of clinical judgment is likely needed, or concurrent use of the Canadian C-Spine Rules to exclude the need for imaging. Midline tenderness as a met criterion was often in the context of poor or absent documentation relating to this, emphasizing the importance of clear and accurate assessments. The distracting injury was identified in 7 out of the 43 patients; however, only one of these patients exhibited a thoracic injury (T11 compression fracture), with the remainder comprising injuries to the extremities – some studies suggest that C-spine imaging may not be required in the evaluable blunt trauma patient despite distracting injuries in any body regions that do not involve the upper chest. This emphasises the need for standardised definitions for distracting injury, at least at a departmental/regional level. The data highlights the currently poor application of the NEXUS guidelines, with likely common themes throughout emergency departments, highlighting the need for further education regarding implementation and potential refinement/clarification of criteria. Of note, there appeared to be no significant differences between levels of experience with respect to inappropriately clearing the c-spine clinically with respect to the guidelines.

Keywords: imaging, guidelines, emergency medicine, audit

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Authors: Hamed Delrobai Ghoochan Atigh

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Androgenic alopecia (AGA) is a common form of hair loss, impacting approximately 50% of females, which leads to reduced self-esteem and quality of life. It causes progressive follicular miniaturization in genetically predisposed individuals. Mesotherapy -- a minimally invasive procedure, topical 2% minoxidil, and oral finasteride have emerged as popular treatment options in the realm of cosmetics. However, the efficacy of mesotherapy compared to other options remains unclear. This study aims to assess the effectiveness of mesotherapy when it is added to topical 2% minoxidil treatment on female androgenic alopecia. Mesotherapy, also known as intradermotherapy, is a technique that entails administering multiple intradermal injections of a carefully composed mixture of compounds in low doses, applied at various points in close proximity to or directly over the affected areas. This study involves a randomized controlled trial with 100 female participants diagnosed with androgenic alopecia. The subjects were randomly assigned to two groups: Group A used topical 2% minoxidil twice daily and took Finastride oral tablet. For Group B, 10 mesotherapy sessions were added to the prior treatment. The injections were administered every week in the first month of treatment, every two weeks in the second month, and after that the injections were applied monthly for four consecutive months. The response assessment was made at baseline, the 4th session, and finally after 6 months when the treatment was complete. Clinical photographs, 7-point Likert scale patient self-evaluation, and 7-point Likert scale assessment tool were used to measure the effectiveness of the treatment. During this evaluation, a significant and visible improvement in hair density and thickness was observed. The study demonstrated a significant increase in treatment efficacy in Group B compared to Group A post-treatment, with no adverse effects. Based on the findings, it appears that mesotherapy offers a significant improvement in female AGA over minoxidil. Hair loss was stopped in Group B after one month and improvement in density and thickness of hair was observed after the third month. The findings from this study provide valuable insights into the efficacy of mesotherapy in treating female androgenic alopecia. Our evaluation offers a detailed assessment of hair growth parameters, enabling a better understanding of the treatments' effectiveness. The potential of this promising technique is significantly enhanced when carried out in a medical facility, guided by appropriate indications and skillful execution. An interesting observation in our study is that in areas where the hair had turned grey, the newly regrown hair does not retain its original grey color; instead, it becomes darker. The results contribute to evidence-based decision-making in dermatological practice and offer different insights into the treatment of female pattern hair loss.

Keywords: androgenic alopecia, female hair loss, mesotherapy, topical 2% minoxidil

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Authors: Hamed Movahedi, Nicolas Bovet, Henning Friis Poulsen

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Following the advent of the Industrial Revolution, there has been a significant increase in the extraction and utilization of hydrocarbon and fossil fuel resources. However, a new era has emerged, characterized by a shift towards sustainable practices, namely the reduction of carbon emissions and the promotion of renewable energy generation. Given the substantial number of mature oil and gas wells that have been developed inside the petroleum reservoir domain, it is imperative to establish an environmental strategy and adopt appropriate measures to effectively seal and decommission these wells. In general, the cement plug serves as a material for plugging purposes. Nevertheless, there exist some scenarios in which the durability of such a plug is compromised, leading to the potential escape of hydrocarbons via fissures and fractures within cement plugs. Furthermore, cement is often not considered a practical solution for temporary plugging, particularly in the case of well sites that have the potential for future gas storage or CO2 injection. The Danish oil and gas industry has promising potential as a prospective candidate for future carbon dioxide (CO2) injection, hence contributing to the implementation of carbon capture strategies within Europe. The primary reservoir component consists of chalk, a rock characterized by limited permeability. This work focuses on the development and characterization of a novel hydrogel variant. The hydrogel is designed to be injected via a low-permeability reservoir and afterward undergoes a transformation into a high-viscosity gel. The primary objective of this research is to explore the potential of this hydrogel as a new solution for effectively plugging well flow. Initially, the synthesis of polyacrylamide was carried out using radical polymerization inside the confines of the reaction flask. Subsequently, with the application of the Hoffman rearrangement, the polymer chain undergoes partial amination, facilitating its subsequent reaction with the crosslinker and enabling the formation of a hydrogel in the subsequent stage. The organic crosslinker, glutaraldehyde, was employed in the experiment to facilitate the formation of a gel. This gel formation occurred when the polymeric solution was subjected to heat within a specified range of reservoir temperatures. Additionally, a rheological survey and gel time measurements were conducted on several polymeric solutions to determine the optimal concentration. The findings indicate that the gel duration is contingent upon the starting concentration and exhibits a range of 4 to 20 hours, hence allowing for manipulation to accommodate diverse injection strategies. Moreover, the findings indicate that the gel may be generated in environments characterized by acidity and high salinity. This property ensures the suitability of this substance for application in challenging reservoir conditions. The rheological investigation indicates that the polymeric solution exhibits the characteristics of a Herschel-Bulkley fluid with somewhat elevated yield stress prior to solidification.

Keywords: polyacrylamide, hofmann rearrangement, rheology, gel time

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Authors: Shiva Mardani, Mehdi Nasr-Esfahani, Majid Olia, Hamid Molahosseini, Hamed Hassanzadeh Khankahdani

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Plant-parasitic nematodes cause serious diseases on plants and effectively reduce food production in quality and quantity worldwide, with at least 17 nematode species in the three important and major genera, including Meloidogyne, Heterodera, and Pratylenchus. Root-knot nematodes (RKN), Meloidogyne spp. with the dominant species, Meloidogynejavanica, are considered as the important plant pathogens of agricultural products globally. The hosts range can be vegetables, bedding plants, grasses, shrubs, numerous weeds, and trees, including forests. In this study, chemical management was carried out on RKN, M. javanica, to investigate the efficacy of Iranian Abamectin insecticide product [acaricide Abamectin (Vermectin® 2% EC, Gyah Corp., Iran)] verses imported normal Abamectin available in the Iran markets [acaricide Abamectin (Vermectin® 1.8% EC, Cropstar Chemical Industry Co., Ltd.)] each of which at the rate of 8 L./ha, on Tomatoes, Solanumlycopersicum L., (No. 29-41, Dutch company Siemens) as a test plant, and the controls (infested to RKN and without any chemical pesticides treatments); and (sterile soil without any RKN and chemical pesticides treatments) at the greenhouse in Isfahan, Iran. The trails were repeated thrice. The results indicated a highly significant reduction in RKN population and an increase in biomass parameters at 1% level of significance, respectively. Relatively similar results were obtained in all the three experiments conducted on tomato root-knot nematodes. The treatments of Gyah-Abamectin (51.6%) and external Abamectin (40.4%) had the highest to least effect on reducing the number of larvae in the soil compared to the infected controls, respectively. Gyah-Abamectin by 44.1% and then external one by 31.9% had the highest effect on reducing the number of larvae and eggs in the root and 31.4% and 24.1% reduction in the number of galls compared to the infected controls, respectively. Based on priority, Gyah-Abamectin (47.4 % ) and external Abamectin (31.1 %) treatments had the highest effect on reducing the number of egg- masses in the root compared to the infected controls, with no significant difference between Gyah-Abamectin and external Abamectin. The highest reproduction of larvae and egg in the root was observed in the infected controls (75.5%) and the lowest in the healthy controls (0.0%). The highest reduction in the larval and egg reproduction in the roots compared to the infected controls was observed in Gyah-Abamectin and the lowest in the external one. Based on preference, Gyah-Abamectin (37.6%) and external Abamectin (26.9%) had the highest effect on the reduction of the larvae and egg reproduction in the root compared to the infected controls, respectively. Regarding growth parameters factors, the lowest stem length was observed in external Abamectin (51.9 cm), with nosignificantly different from Gyah-Abamectin and healthy controls. The highest root fresh weight was recorded in the infected controls (19.81 gr.) and the lowest in the healthy ones (9.81 gr.); the highest root length in the healthy controls (22.4 cm), and the lowest in the infected controls and external Abamectin (12.6 and 11.9 cm), respectively. Conclusively, the results of these three tests on tomato plants revealed that Gyah-Abamectin 2% compared to external Abamectin 1.8% is competitive in the chemical management of the root nematodes of these types of products and is a suitable alternative in this regard.

Keywords: solanum lycopersicum, vermectin, biomass, tomato

Procedia PDF Downloads 96