Theses supervised by Dr. Öğr. Üyesi İbrahim Koç
11 theses · Bitlis Eren University, Altınbaş University
Pestisit uygulanmış vermikompostlarda Eisenia foetida'nın bazı biyolojik parametreleri
Bu çalışma, pestisit uygulanmış vermikompostlarda bulunan kırmızı Kaloforniya solucanı (Eisenia foetida) kokonlarından çıkan solucan sayısı, solucanların ağırlıkları ve yumurtladıkları kokon sayısı gibi bazı biyolojik parametreleri belirlemek amacıyla yapılmıştır. Çalışma in-vitro şartlarında, Tesadüf Parselleri Deneme Düzeninde 5 tekerrürlü olarak yürütülmüştür. Çalışmada, Muş ilinde çokça kullanılan bazı pestisitlerin önerilen ve 4 alt dozu kullanılmış olup kontrol grubuna sadece şebeke suyu verilmiştir. Uygulamada 100 gr vermikompost konulmuş 300 cm3'lük plastik kaplara 10'ar adet kokon yerleştirilmiş, ortamın sıcaklığı 20-29 oC ve nem oranı %70-90 arasında tutulmuştur. Araştırma; kokonlardan çıkan yavru bireylerin, tekrar kokon vermesine kadar devam etmiştir. Pestisit muamelelerinin belirlenen özelliklere etkisinin araştırılmasında Tek Yönlü Varyans Analizi Tekniğinden (One-way ANOVA), farklı grupların belirlenmesinde ise TUKEY Çoklu Karşılaştırma Testi'nden yararlanılmıştır. Yapılan varyans analizi sonucunda; solucan ağırlığı bakımından fungisit dozları arasında istatistiksel olarak önemli farkların bulunmadığı (P=0.113), buna karşın insektisit ve herbisit dozları bakımından söz konusu farkların önemli olduğu görülmüştür (P=0.000). Kokon ve solucan sayıları bakımından ise pestisit dozları arasında önemli farkların bulunduğu görülmüştür (P=0.000).
Bitlis ili ve çevresindeki kaynak sularının bazı mikrobiyolojik ve fizikokimyasal özelliklerinin araştırılması
Bu çalışma, Bitlis İlinde insani tüketim amaçlı kullanılan Başhan, Papşin, Kanimiyan, Seyit Bulağı, Altunkalbur, Çam Sitesi ve Mezra doğal kaynak sularının bazı fizikokimyasal ve mikrobiyolojik özelliklerini belirlemek amacıyla yapılmıştır. Kaynaklardan alınan su örnekleri, İnsani Tüketim Amaçlı Sular Hakkında Yönetmeliğinin (25730, 17.02.2005) numune alma usullerine göre, kurak (Eylül 2019) ve yağışlı (Mayıs 2020) dönemleri temsil edecek şekilde alınmış ve değerlendirilmiştir. Mikrobiyolojik analizler için, membran filtrasyon, yayma plaka ile dökme plak yöntemleri ve fizikokimyasal analizler için standart tayin metotları kullanılmıştır. Sonuç olarak: Mikrobiyolojik parametreler açısından, Seyit Bulağı, Altunkalbur, Başhan ve Mezra kaynaklarının koliform bakteri yönünden; Başhan, Papşin, Mezra ve Seyit Bulağı kaynaklarının Enterokok yönünden; Seyit Bulağı, Altunkalbur, Başhan ile Mezra kaynaklarının 22 °C'de toplam koloni sayısı yönünden ve bütün kaynakların Pseudomonas aeruginosa yönünden içme standartlarına uygun olmadığı tespit edilmiştir. Fizikokimyasal parametreler açısından araştırılan kaynakların kullanıma uygun olduğu görülmüştür. Mikrobiyolojik açıdan kirlilik muhteva eden bu kaynakların ilgili kurumlarca periyodik olarak izlenmesi, kirlilik etmenlerinin engellenmesine yönelik iyileştirici çalışmaların yapılması ve bu konuda civar halkın bilgilendirilmesi gerektiği düşünülmekte ve önerilmektedir.
Bitlis ilinde tarımsal faaliyetlerde kullanılan bazı pestisitlerin toprak nematodları ve mikroorganizmaları üzerindeki etkilerinin araştırılması
Bu çalışma, Bitlis İli'nde tarımsal alanlarda yaygın bir şekilde kullanılan Pyridaben (%20, akarisit), Pendimethalin (330 g/l, herbisit), Penconazole (100 g/l, fungusit) ve Chlorpyrifos-methyl (227 g/l, insektisit) etkili pestisitlerinin hedef olmayan toprak nematod, aerob mezofil bakteri ile mikrofungus komüniteleri ve pH'sına etkilerini belirlemek amacıyla yapılmıştır. Çalışma, in-vitro şartlarında tekrarlı ölçümlerde varyans analizi yöntemine göre altı tekerrürlü olarak yürütülmüştür. Belirlenen pestisitler, birer kg'lık toprak numunelerine, enjektör yardımıyla, önerilen dozda muamele edilmiştir. Yapılan varyans analizlerine göre Periyot×Muamele interaksiyonlarının sırasıyla pH, bitki paraziti ve fungivor nematodlar için önemli olduğu (P=0.007; P=0.008; P=0.000), omnivor-avcı, bakterivor ve toplam nematodlar için hem Periyot (P=0.000; P=0.000; P=0.000) hem de muamelelerin ana etkisinin istatistiksel olarak önemli olduğu (P=0.046; P=0.017; P=0.009) bulunmuştur. Profil analizlerine göre; pH'sın, özellikle Pyridaben muamelesinde artış gösterdiği; aerob mezofil bakteri sayısının, kontrol muamelesinde artmasına karşın tüm pestisit muamelelerinde azalma gösterdiği; mikrofungus sayısının, Penconazole muamelesinde artış göstermesine karşın diğer muamelelerde azaldığı; bitki paraziti, fungivor ve toplam nematod sayılarının tüm pestisit muamelelerinde azaldığı; omnivor-avcı ve bakterivor nematodların kısmen etkilendiği görülmüştür. Sonuç olarak; kullanılan pestisitlerin, çalışılan hedef dışı toprak parametreleri üzerinde, ilacın çeşidi ve dikkate alınan parametrelere göre az veya çok, olumlu veya olumsuz etkili olduğu saptanmıştır. Ek olarak, pestisit toksisite testlerinin mümkün olduğunca geniş kapsamda yapılması, üreticilerin kullandıkları pestisitlerin hedef dışı canlı ve faktörleri de etkileyebileceği hassasiyet ve bilincinde kullanılması gerektiği düşünülmekte ve önerilmektedir.
Kabuk ve boru eşanjörünün dış kabukuna helis boru eşanjör yerleştirilmesiyle ısı transferinin artırılmasının incelenmesi
This study investigates the enhancement of heat transfer in shell-and-tube heat exchangers , which are crucial in key industries such as energy, petroleum, and electrical power production. The focus is to assess the impact of adding a helical coil to these exchangers, a practice often utilized in refractory technology, to improve their efficiency. The approach includes a detailed numerical analysis of two HE models. The first is a conventional STHE, while the second is an innovative variant with a helical coil added to its outer shell. This modification aims to improve the HT process between oil and water. The study's findings reveal that the second model, with the helical coil, significantly enhances the HEs efficiency. This conclusion is drawn from comprehensive numerical simulations, highlighting the effectiveness of this design change. The originality of this thesis lies in its approach to combining traditional design elements with innovative modifications to improve HE efficiency. This strategy offers a practical solution for increasing thermal efficiency in industrial applications, marking a significant advancement in energy-efficient design practices.
5 fonksiyonlu stop lambası termal analizi
The light-emitting diodes used in automotive lighting systems and many areas are high heat sources. The heat generated in the light-emitting diodes must be removed from the environment without damaging the light-emitting diodes and the system. In thesis study, the heat and light losses that may occur in the light-emitting diodes as a result of the operation of a stop lamp with 5 functions were controlled. To increase the accuracy of the computational fluid dynamics analysis, the printed circuit board parts were tested and compared with the analysis result. According to the results of the analysis, high-temperature changes that may occur in the product parts were investigated. According to the colors of the light-emitting diodes, the temperature-dependent light drops were investigated. To reduce the temperature on the printed circuit board, the effects of changing the structure of the circuit paths and vias on the temperature of the circuit board were investigated. Changing the circuit paths provides the temperature drop. Passing the copper circuit through the heat zone without leaving a gap path lowers the temperature.
Experimental and numerical study of solar water heater enhancement integrated with phase change material and heat exchanger
In current work a practical and numerical study to improve solar energy storage by using PCM and helical coil tube heat exchangers. These components were incorporated into flat solar plate collectors and storage tanks. Phase change material covered the heating water pipe inside the collector, while suitable capsules were fixed inside the storage tank. The teat exchange using helical coils was added to the storage tank as an external load. The experimental trials were conducted in four separate months (September 2021, April, May, and June 2022), especially on the first day of every month. The experimental section of the present work was conducted in Basra city in Iraq (30.5o N Lat.,47.78o E Long.). During the course of the study, the influence of factors such as air and water temperature, the amount of solar radiation, and the volume flow rate of inlet water were analyzed. For numerical study, ANSYS-FLUENT 2020 R1 was used to employ the finite volume method FVM for resolving Navier-Stock, energy, and standard k –ε model equations to assess system performance and the influence of flow rate and input temperature on the system. The effectiveness, heat gain, and significance of the phase change material in increasing heating efficiency throughout the day were studied using a range of variables, including inlet water volume flow rate (2, 3, 4, 6, and 8 L/min) and inlet water temperature (25, 30, and 35 C) respectively. The results illustrate that a low starting water temperature of 25°C enhances the daily efficiency range from 58% to 65% and that the daily final collector outlet temperature was over 65 °C. The results also indicate a noticeable increase in the time of water heating in the absence of the sun due to the heat emitted by the PCM, which can be observed in the evening hours. Finally, the comparison between the practical and numerical works shows well compatibility between both works where the error in between both works does pass (2 %) assuring the validity of the used numerical study.
Improving thermal efficiency of photovoltaic thermal systems
Photovoltaic panels can convert solar energy directly into electricity, but their efficiency declines as the panels' temperature rise. To solve this problem, Photovoltaic thermal (PVT) systems have been developed to enhance power energy generation from Photovoltaic panels. This research presents the daily and monthly global solar radiation on a horizontal surface in Iraq and applies it to the PVT water system. The thesis contributes in two ways: first, it models a novel copper pipe system that improves thermal efficiency in an actual environment, and second, it investigates the hourly and daily intensity of solar radiation in Iraq. Using collected irradiation at mass flow rates ranging from 0.01 and to 0.02 kg per second, the surface temperature of the PVT model was calculated. Using the experimental data, the surface temperature was also computed in the PVT model. The findings were essentially consistent with those of prior investigations. A PVT system with a constant input temperature is employed to raise the surface temperature throughout simulated testing. This research considers the four unique seasons' weather conditions. With an optimal mass flow rate of 0.02 kg/s and a constant low input temperature, the findings demonstrate the thermal efficiency of the PVT.
Malzeme ve geometrik parametrelerin soğutucu ısı verimi üzerine etkisinin sayısal analizi
The challenge for designers is to try to make electronic boards smaller. From this point of view, in this study, the size of a heat sink installed on a central processing unit for a computer that generates 100 W was reduced to 50 % by changing the type of metal as well as adding a modification to the geometric shape of the fin. A numerical investigation was conducted for the results of a practical experiment. Six different types of heat sinks, differing from each other in terms of fin shape, were designed using commercial design software, taking into consideration the uncomplicated design, ease of manufacture, and cost avoidance. The material of the heat sink was copper, all designs were of the same sizes, the comparison was conducted to evaluate the efficiency fairly. After the computational fluid dynamics simulation tool was set under forced convection conditions, and the cooling airflow velocity was set in a laminar form, which was set to 1 m/s. The comparison was based on the pressure difference as well as the thermal resistance, it was shown that separated short angled plate fins were superior to the rest designs as it had the lowest thermal resistance 0.3610 ℃/W, but on the other hand, recorded the highest-pressure difference which was 5.6340 Pa, thus was the worst for the pressure difference. The results showed that the intermittent zigzag fins were superior in terms of pressure difference, which had the lowest value of 3.2040 Pa, but on the other hand, it was the worst in terms of thermal resistance, as it recorded the highest value 0.4720 ℃/W. Through all of the above, it can be concluded that the process of reducing the size of the heat sink to 50% was completed by changing the type of material as well as making some modifications to the design of the fin, and in addition to that, the geometric shape of the fin affects the performance of the heat sink where it was evident in each of the pressure difference as well as of thermal resistance factors.
Thermal performance improvement of shell and helical coil heat exchanger
Nowadays, energy consumption increases so it is necessary to enhance the efficiency and performance of heat energy transition. The effects of perforated twisted tape on heat transfer factor, effectiveness, Nusselt number, and pressure drop are studied numerically. Modeling of HE with the perforated twisted tape is applied where finite volume manner is utilized to perform the setup and complete the solution. Validation of numerical results and experimental previous results is done and there is an excessive settlement between the numerical and experimental results. The range of Res is from 3800 to 18000. The results indicated that the U rises with the rise of Re where the perforated twisted tape achieves the extreme improvement of heat transfer coefficient achieving the numbers from 965 to 1250 W/m2K. The perforated twisted tape has the highest ratio of enhancing Nu following the numbers from 65 to 115 and this can be explained as the velocity rises, the turbulence level increases. HE effectiveness increases with the growth of Re where the perforated twisted tape attained the supreme enhancement of effectiveness reaching the numbers from 0.35 to 0.85. It is indicated that the twisted tape configuration has the maximum ratio of ΔP increase as the complicity of twisted tape rise the ΔP. Contours and streamlines of hot and cold water cross the HE explains the
Experimental and numerical study of heat transfer in double-pipe helical heat exchanger using nano-liquid
In this study, convection heat transfer coefficient and friction factor in double-pipe helical heat exchanger are investigated using nano-liquid of silicon dioxide and water as a base liquid experimentally and numerically. Parallel and counter flows inside the double-pipe helical heat exchanger with variations of Reynolds from 3400 to 11400 are studied. The experimental setup is used to complete all the studies under different conditions. Different concentrations of nanofluids of silicon dioxide with water (eg. 0.0625%, 0.125%, 0.25%, 0.5%) and pure water are investigated. The findings reveal that the heat transfer coefficient is increases with the rise of Reynolds number and nanofluids concentration where the 0.25% concentration achieved the maximum enhancement in parallel and contour flow with numbers 5.5 to 19 kW/m2∙K and 7 to 25 kW/m2∙K, respectively. Nusselt number enhanced with the increase of Reynolds number for all cases since the water velocity growth more turbulence levels increase. The Nu of the parallel and contour flow is from 36 to 95 and 45 to 123, respectively. The 0.25 Vol% concentration reaches the optimal Nu enhancement of a double-pipe helical heat exchanger. Friction factor reduce with the rise of Reynolds number where the highest friction factor value is achieved in the case of 0.5% nanofluid concentration. The pressure drop increased with the rise of solid particles concentrations as the resistance of water fluid flow grows with the increase of pressure drop. The streamlines and contours of temperature, velocity, and pressure inside the inner tube and annulus tubes are investigated. It is concluded that the 0.25% concentration of nanofluids is the optimum concentration for enhancement heat transfer inside the double pipe heat exchanger.
Numerical investigation of heat transfer, pressure drop, and exergy for plate heat exchanger using nanofluids
In this thesis, a numerical investigation is presented on a Plate Heat Exchanger (PHE) using water (Titanium nitride) nanofluid. Reynolds numbers were changed to work (Nu), (f) and exergy loss. The finite volume method was used for numerical analysis and the simulation results were confirmed with previous experimental results. The effects of different operating factors on (U), (Nu) and (f) and temperature, velocity and pressure distribution, such as the weight concentration of the hot side nanofluid and (Re) 2540 to 12700, were investigated. The results showed that U (Res) and nanoparticles increased with increasing weight fraction, where nanofluids with 0.5% concentration reached the highest values and the development rate started from 123.5-133.5%. (Nu) increases with increasing Reynolds number and volume concentration of nanofluids where 0.5 wt% concentration (wt%) (Tin-water nanofluid) scores the highest (Nu) values from 43 to 68. (f) decreases with increasing (Re), where the case of 0.6% Tin to water concentration recorded extreme (f) with values from 0.18 to 0.35. The exergy loss of nanofluids at different concentrations increases with (Re) growth and 0.5 wt% concentration. % (Tin-su) achieved the highest exergy loss after numbers from 50 to 66%. Flowlines and contours of the temperature, velocity and pressure distribution within the (PHE) provide reliable explanations for the movement of cold and hot water and the improvement of heat transfer. Keywords: Plate Heat Exchanger, Heat transfer, Pressure drop, Nanofluids, Numerical study