Radiated Research Articles

Low-dose radiation decreases Lrrk2 levels in the striatum of large mammalian brains: New venues to treat Parkinson's disease?

IntroductionAmong gene mutations and variants linked to an increased risk of PD, mutations of leucine-rich repeat kinase 2 gene (LRRK2) are among the most frequently associated with early- and late-onset PD. Clinical and neuropathological characteristics of idiopathic-PD (iPD) and LRRK2-PD are similar, and these similarities suggest that the pathomechanisms between these two conditions are shared. LRRK2 mutations determine a gain-of-function and yield higher levels of lrrk2 across body tissues, including brain. On another side, recent animal studies supported the potential use of low dose radiation (LDR) to modify the pathomechanisms of diseases such as Alzheimer's disease (AD). MethodsWe assessed if a single total-body LDR (sLDR) exposure in normal swine could alter expression levels of the following PD-associated molecules: alpha-synuclein (α-syn), phosphorylated-α-synuclein (pα-syn), parkin, tyrosine hydroxylase (th), lrrk2, phosphorylated-lrrk2 (pS935-lrrk2), and some LRRK2 substrates (Rab8a, Rab12) across different brain regions. These proteins were measured in frontal cortex, hippocampus, striatum, thalamus/hypothalamus, and cerebellum of 9 radiated (RAD) vs. 6 sham (SH) swine after 28 days from a sLDR of 1.79Gy exposure. ResultsWestern Blot analyses showed lowered lrrk2 levels in the striatum of RAD vs. SH swine (p < 0.05), with no differences across the remaining brain regions. None of the other protein levels differed between RAD and SH swine in any examined brain regions. No lrrk2 and p-lrrk2 (S935) levels differed in the lungs of RAD vs. SH swine. ConclusionsThese findings show a specific striatal lrrk2 lowering effect due to LDR and support the potential use of LDR to interfere with the pathomechanisms of PD.

Low-dose brain radiation: lowering hyperphosphorylated-tau without increasing DNA damage or oncogenic activation

Brain radiation has been medically used to alter the metabolism of cancerous cells and induce their elimination. Rarely, though, brain radiation has been used to interfere with the pathomechanisms of non-cancerous brain disorders, especially neurodegenerative disorders. Data from low-dose radiation (LDR) on swine brains demonstrated reduced levels of phosphorylated-tau (CP13) and amyloid precursor protein (APP) in radiated (RAD) versus sham (SH) animals. Phosphorylated-tau and APP are involved in Alzheimer’s disease (AD) pathogenesis. We determined if the expression levels of hyperphosphorylated-tau, 3R-tau, 4R-tau, synaptic, intraneuronal damage, and DNA damage/oncogenic activation markers were altered in RAD versus SH swine brains. Quantitative analyses demonstrated reduced levels of AT8 and 3R-tau in hippocampus (H) and striatum (Str), increased levels of synaptophysin and PSD-95 in frontal cortex (FCtx), and reduced levels of NF-L in cerebellum (CRB) of RAD versus SH swine. DNA damage and oncogene activation markers levels did not differ between RAD and SH animals, except for histone-H3 (increased in FCtx and CRB, decreased in Str), and p53 (reduced in FCtx, Str, H and CRB). These findings confirm the region-based effects of sLDR on proteins normally expressed in larger mammalian brains and support the potential applicability of LDR to beneficially interfere against neurodegenerative mechanisms.

Miniature 4-Element MIMO Antenna System Designed From Transparent Glass Substrate and Aluminum Foil Radiator

The use of transparent antennas has been gaining popularity in recent years. Today many types and designs of display apparatus can be seen along city streets and for buildings as a backup power supply. Transparent antennas can be used for cladding the modern glass buildings. Transparent antennas also can be placed directly on top of solar cells and resolve the issue of competing for limited surface real estate. Like integration with the solar panels of small satellites, where limited surface area is an issue for mounting antennas, solar cells, and space instruments. This paper discuss the methods and materials used to design a transparent antennas that can be integrated with solar cells to solve the issue of competing for limited surface real estate and backup the short of electricity in the sunny country Sudan. In this paper a proposed a 4-element meander line MIMO Multiple Inputs Multiple Outputs antenna system designed from Aluminum foil radiator over transparent glass substrate this design is transparent partially. Despite of the unfamiliar materials used for the antenna design and it is a limited size MIMO system the simulated and measured results showed XBand matched bandwidth. In this work the antenna is designed and the solar cell module has been proposed theoretically.

Morphological studies on legume and hilum in seven species of Vigna Savi (Fabaceae)

In this study of different taxa of genus Vigna the macro and micromorphological characters were investigated. These taxa collected from different countries (3 cultivated and 8 annual or perennial herbs) representing 7 species of this genus, namely: Vigna radiate, Vigna trilobata, Vigna vexillata, Vigna caracalla, Vigna pubescens, Vigna unguiculata, and Vigna luteola. Legume features such as shape, colour, size, surface texture, number of locules, number of legumes per peduncle seed set percentage, orientation. Moreover, by using scanning electron microscopy, additional details were obtained for stomatal shape, size, type, cuticular and wax ornamentation of the surface of the mature pod, including details of the seed such as hilum shape, size, position, ornamentation based on scanning electron microscope evidence. The usefulness of the macro and micromorphological features as criteria for taxonomic identification was emphasized. Key words: Vigna, Fabaceae, morphological characters, pod, hilum, S.E.M., taxonomy.

Dynamic radiator threat assessment based on CRITIC-TOPSIS

Dynamic radiator threat assessment based on CRITIC-TOPSIS

Living your Best Life and Radiating Positivity: Exploratory Conceptions of Wholesome Memes as The New Sincerity

From commercial advertising to political messaging, internet memes have proven to be among the most prevalent and pervasive forms of communication online. The so-called “wholesome meme” is a subversive genre of meme that arose in early 2016 as a reaction to increasing geopolitical turbulence and cultural polarization. Wholesome memes are defined by their bold positivity and feature loving friendships, cute animals, and heartwarming stories. As an early attempt to theorize this emerging phenomenon, this paper argues that wholesome memes can be considered part of the larger post-postmodernist literary movement, The New Sincerity. Synthesizing expressions of irony and sincerity, these memes may signal a shift in the character and attitude of internet culture from anti- to pro-social and speak to the desire of people to seek meaning and fulfillment. De la publicité aux message politiques, les mèmes s'avèrent désormais être parmi les formes de communication en ligne les plus répandues. Le soi-disant « wholesome meme » (mème sain) est un genre subversif de mèmes qui a surgi au début de 2016 en réaction à la turbulence géopolitique croissante et à la polarisation culturelle. Les mèmes sains se caractérisent par leur positivité audacieuse et démontre des situation amicales, des animaux adorables et des histoires réconfortantes. En tant que première tentative de théoriser ce phénomène émergent, cet article soutien que les mèmes sains peuvent être considérés comme faisant partie du mouvement littéraire post-postmoderniste du New Sincerity. Synthétisant des expressions d'ironie et de sincérité, ces mèmes peuvent signaler un changement dans le caractère et l'attitude de la culture Internet, passant d'anti- à prosocial et d'aborder le désir des gens de trouver un sens et de se réaliser en tant que personne.

Too Much, Too Fast, Too Novel: A Case of Rhabdomyolysis

Our patient is a 17-year-old Hispanic female with a past medical history of nephrolithiasis. She presented to clinic with bilateral thigh pain. 3 days prior to presentation she attended a cycling class that “required her to push herself”. Approximately 10 minutes into the exercise she “felt winded but then felt a second wind”. Immediately after the class the patient began to feel bilateral thigh pain that was constant, 10/10, did not radiate, and was exacerbated by walking, particularly painful walking downstairs, and any movement that requires bending at the …

Effects of Radiation and Triaxiality of Primaries on Existence and Stability of Collinear Equilibrium Points in Elliptical Restricted Three Body Problem

This paper deals with the motion of infinitesimal mass around primaries whose are radiating and triaxial. They are moving around each other in elliptic orbits about the common barycenter in the neighborhood of collinear equilibrium points. It is observed that location and stability of collinear points are effected by radiation and triaxiality of primaries. The results shows that collinear points \(L_1\) and \(L_2\) are having unstable behavior, while \(L_3\) is showing stable behavior for some values of radiation and triaxiality.

Research on terahertz radiation peak control of photoconductive antenna

This paper studies the interaction effect between the micro-structure photoconductive antenna (PCA) and femtosecond laser, the control of radiated terahertz (THz) wave, and the radiation regulation mechanism of the THz wave for the photoconductive antenna (PCA). The Drude-Lorentz theory model is used to solve the photocurrent density, which is then iterated to the excitation grid by FDTD method. And then the time-varying electromagnetic fields is solved by Maxwell’s equations. The radiated THz wave from the near field to far field in the multi-layer medium is got through the Green's Function of transmission line, and the relationship between the photocurrent and impedance of the radiation is established. At the same time, the relationship between the photocurrent and the magnetic resonance model is also established. The control mechanism of THz wave radiation from micro-structure S-shaped PCA is analyzed by simulation. The results show that the radiation impedance of the equivalent model is changed after split ring resonator (SRR) is introduced into the H-shaped PCA. Meanwhile, it is known that the coupling effect exists when the coupling coefficient is not zero. With the increasing of the coupling coefficient, and the radiation intensity of the resonance frequency peak increases and shifts. The adjusting range of the center frequency between 0.50−0.80 THz, the frequency modulation degree is 75%, and the peak radiation efficiency increases by 70% after simulating the S-shaped PCA. This work lays an important foundation for the design of THz wave resonance center frequency range and structure of high-power PCA.

Revisiting Ghostown, the Radiators, Tony Visconti and the sound of punk: An interview with Pete Holidai

Revisiting Ghostown, the Radiators, Tony Visconti and the sound of punk: An interview with Pete Holidai

A study on radiated interference emitted by power tool appliances within 30 MHz to 1 GHz

A study on radiated interference emitted by power tool appliances within 30 MHz to 1 GHz

Cytomorphological characteristics evaluation of the third generation of arrowroot plant (Maranta arundinacea L.) radiated by gamma ray

Arrowroot plants (Maranta arundinacea L.) have enormous potential to be developed as the alternative foods. Various kinds of functional food products can be processed from arrowroot tubers, because they have lower calories and IG (Glycemic Index) contents compared to the other tubers. The study aimed to determine the characteristics of the phenotype, productivity and anatomy of leaves of arrowroot plants radiated by gamma ray. The study used factorial randomized block design with 2 factors. The first factor was arrowroot accessions (Pulosari, 25 Pandeglang, Cikondang, Tamansari, and MN-1), and the second factor was radiation dose (0, 10, 20, 30, 40, 50 Gray), and those was arranged in three replications. Based on the results of the study, it found that: Pulosari accession without radiation and 30 Gray radiation required the fastest time of 12 days for shoots growth. The highest plant growth (106,88cm) was Cikondang accession with 20 Gray radiation treatment; while the shortest plant (59.61cm) was found in Cikondang accession with 30 Gray radiation dose as well. The number of productive tillers (3.0) was mostly found in Pulosari accession without radiation, conversely, the least (0.72) was found in MN-1 accession with 20 Gray radiation. For the maximum number of out-of-section tillers (1.17) on the 25 Pandeglang accession with 40 Gray radiation. The longest leaf growth (22.64 cm) and the widest (9.08 cm) were found in Cikondang accession without radiation, conversely, the shortest leaf growth (10.17 cm) and smallest (3.34 cm) was found in Cikondang accession radiated by 40 Gray. There were no changes to the number and shape of the stomata between the control plants and the radiated treatment, but there were changes in leaf color on 25 Pandeglang accession with radiation treatment 40 Gray.AbstrakTanaman Garut (Maranta arundinaceaL.) memiliki potensi besar untuk dikembangkan sebagai pangan alternatif. Berbagai macam produk pangan fungsional dapat diolah dari umbi Garut, karena memiliki kandungan IG (Index Glycemic) dan kalori lebih rendah dibandingkan umbi-umbi lainnya. Penelitian ini bertujuan untuk mengetahui karakteristik fenotipe, produktivitas dan anatomi daun tanaman Garut yang diberi perlakuan radiasi sinar gamma. Penelitian disusun menggunakan Rancangan Acak Kelompok (RAK) Faktorial dengan 2 faktor, dengan faktor pertama aksesi tanaman (Pulosari, 25 Pandeglang, Cikondang, Tamansari, dan MN-1), dan faktor kedua adalah dosis radiasi (0, 10, 20, 30, 40, 50 Gray), penelitian terdiri dari 3 ulangan. Berdasarkan hasil penelitian diketahui bahwa aksesi Pulosari tanpa radiasi dan radiasi 30 Gray memerlukan waktu keluar tunas paling cepat yaitu 12 hari. Pertumbuhan tanaman paling tinggi (106,88 cm) adalah aksesi Cikondang dengan perlakuan radiasi 20 Gray, sedangkan tanaman paling pendek (59,61 cm) juga terdapat pada aksesi Cikondang dengan dosis radiasi 30 Gray. Jumlah anakan produktif (3,0) paling banyak terdapat pada aksesi Pulosari tanpa radiasi, sebaliknya yang paling sedikit (0,72) terdapat pada aksesi MN-1 radiasi 20 Gray. Untuk jumlah anakan keluar ruas paling banyak (1,17) pada aksesi 25 Pandeglang dengan dosis radiasi 40 Gray. Pertumbuhan daun paling panjang (22,64 cm) dan paling lebar (9,08 cm) selama pengamatan terdapat pada aksesi Cikondang tanpa radiasi. Sebaliknya pertumbuhan daun paling pendek (10,17 cm) dan kecil (3,34 cm) juga terdapat pada aksesi Cikondang dan radiasi 40 Gray. Tidak terdapat perubahan terhadap jumlah dan bentuk stomata antara tanaman kontrol dengan perlakuan radiasi, akan tetapi terdapat perubahan warna daun pada aksesi 25 Pandeglang dengan perlakuan radiasi 40 Gray.

Reconstruction of Hematopoietic Function of Human Placental Hematopoietic Stem Cells in Non-Lethally Radiated Mice

To investigate the effect of human placental hematopoietic stem cells (PHSCs) on hematopoietic reconstruction in non-lethally irradiated mice. Human placental HSCs were extracted by mechanical method combined with zymolysis and were identified by flow cytometry and colony formationtest. Twenty-five NOG mice were divided randomly into 4 groups: the blank control group (n=5), the irradiated group (n=4), the low dose PHSC group (n=8) and the high dose PHSC group (n=8). The mice in the irradiated, the low dose and the high dose PHSC groups were irradiated with X-rays at dose 1 Gy (100 cGy/min) under sterile condition. The mice in the low dose PHSC group and the high dose PHSC group were injected intravenously with 0.1 ml human placental HSC in dose of 2×106 and 1×107, respectively. The mice in the blank control and the irradiated group were injected with the same volume of saline. The mice were weighed weekly, and the changes of body weight were calculated. The peripheral blood was collected from each group at 4, 8 and 12 week for flow cytometrytic detection of human CD45+ and myeloid and lymphoid cells. The flow cytometry and cell-colong formation test showed that the human placental HSC accounted for more than 0.75% of total placental mononuclear cells, moreover possess the differentiation ability. Compared with the blank control group, the relative weight gain in the irradiated, the low dose PHSC, and the high dose PHSC groups decreased significantly, and the relative weight gain in the low dose PHSC and the high dose PHSC group increased significantly as compared with the irradiated group. Flow cytometry showed that at the tine-point of 12 weeks after transplantation, the human blood immune system in the high-dose PHSC mice began long-term reconstruction, while the ratio of human CD45+ cells in the low-dose PHSC mice was very low. After transplantation of human PHSC the non-lethally irradiated mice can obtain short-term and long-term reconstruetion of human blood cells, which demonstrated that human placental HSC can differentiate and reconstruct hematopoietic function in vivo of irradiated mice.

NON-CONVENTIONAL APPROACHES FOR THE MANAGEMENT OF ANGINA

Angina is usually classified as a symptom of an underlying cardiovasculardisease which is one of the most common disorder that is affecting the human lifenow a days. It is presented as a throbbing chest pain that can radiate to left armand back due to ischemia of major vessel supplying blood to heart. Several drugclasses and their combination has long been used to treat angina for e.g. Nitrates,Nitrites, Calcium channel blockers, Beta blockers and sodium channel blockersto improve the demand vs supply ratio of oxygen so that the heart muscles canperform its function effectively. The increasing prevalence of disease andresulting resistance to conventional therapy has urged scientists to find otherways that can help in the management of this disease. Cardiovascular andconsequently angina is thus the focus of many studies. In this review a number ofstrategies and their associated mechanisms has been discussed which includeLife style modification, Yoga, Acupuncture therapy, Herbal treatment , L-arginine,L-carnitine, Omega 3 fatty acids, Gene therapy, Cell therapy, Chinese Medicine,and Interventions like Spinal cord Stimulation, Percutaneous coronaryintervention, Enhance external counter pulsation, Extracorporeal shockwavemyocardial revascularization, Transmyocardial laser revascularization,transcutaneous electrical nerve stimulation, percutaneous retrograde coronarysinus perfusion. Coronary sinus perfusion, Coronary sinus reducer, Videothoracoscopic sympathectomy (VTSY) may help in short term and long-termmanagement of angina

Механічна міцність гідроакустичних циліндричних випромінювачів з внутрішніми екранами

Проведені дослідження частотних і кутових характеристик амплітуд коливальних швидкостей циліндричних випромінювачів у внутрішньому об’ємі яких, заповненому рідиною, розміщені акустичні екрани в залежності від відстані між п’єзокерамічною оболонкою випромінювачів та екраном. Здійснена оцінка на їх основі можливостей механічної міцності випромінювачів. Показано, що така технічна реалізація гідроакустичних випромінювачів створює ряд переваг, цікавих з точки зору підвищення ефективності гідролокаційних станцій. Встановлено, що коливальна швидкість реальних джерел звуку суттєво залежить як від внутрішнього імпедансу, так і від реакції зовнішнього оточуючого середовища, оскільки джерела звуку відзначаються конечними значеннями свого внутрішнього механічного опору. Тому зміною звукового поля у внутрішній порожнині перетворювача можливо управляти параметрами його механічного поля. При роботі гідролокаційних станцій в режимі випромінювання в області низькочастотних резонансів екранованих перетворювачів суттєво збільшується небезпека механічного руйнування перетворювачів гідроакустичних антен в зв’язку з різким збільшенням амплітуд їх коливальних швидкостей та появою можливості перевищення амплітудами коливальних швидкостей значень, допустимих з точки зору механічної міцності. Ця обставина повинна враховуватись при побудові генераторних пристроїв трактів випромінювання гідролокаційних станцій.

Feasibility of constructing a unilateral sudden sensorineural hearing loss machine learning classification model based on diffusion tensor imaging

Objective To explore the feasibility of constructing a machine learning classification model for unilateral sudden sensorineural hearing loss (SSHL) patients and normal controls based on diffusion tensor imaging. Methods Prospective collection of 84 patients with untreated SSHL were recruited from the otolaryngology department of the Union Hospital of Tongji Medical College of Huazhong University of Science and Technology between June 2013 to May 2015 as the SSHL group. Meanwhile, a total of 63 healthy volunteers who were no any ear disease history, and the hearing function were confirmed with pure tone audiometry, were collected as the control group. All subjects underwent a brain DTI scan. The data were divided into the training set and validation set according to the ratio of 7 to 3, that was, the training set contained 58 cases of SSHL patients and 44 control groups, and the validation set included 26 cases of SSHL patients and 19 control groups. A vector which included the DTI parameters such as fractional anisotropy, mean diffusivity, axial diffusivity and radial diffusivity was constructed with the software R. The LASSO regression of machine learning method was used to perform feature dimensionality reduction and construct a classification model. The training set samples were used to map the nomogram based on the multivariate logistic analysis method, the validation set and the AUC were used to evaluate the prediction ability of the nomogram, and the calibration curve was used to evaluate the model. Results From the 200 feature vectors including the fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) values of each brain region, after each dimension reduction process, a total of six features were retained, which were the MD of left superior corona radiate and right superior fronto-occipital fasciculus, the AD of the body of corpus callosum, and the RD of left inferior cerebellar peduncle, left superior corona radiate and right posterior limb of internal capsule. The six features of patients with unilateral SSHL were higher than the control group, and the difference was statistically significant (P<0.05). Based on this, a two-class model is constructed and a nomogram is drawn. The sensitivity, specificity, accuracy and AUC of the training set were 93.1% (54/58), 72.7% (32/44), 84.3% (86/102) and 0.854, respectively; the sensitivity, specificity, accuracy and AUC of validation set were 80.8% (21/26), 84.2% (16/19), 82.2% (37/45), 0.870, respectively. Nomogram could significantly improve the classification efficiency of the control group and patients, and the model with the LASSO method showed a higher prediction curve than other models. Conclusions The machine learning classification model based on DTI metrics can effectively distinguish patients with unilateral sudden sensorineural deafness from healthy control people. Key words: Hearing loss, sensorineural; Diffusion tensor imaging; Machine learning; Classification; Nomogram; Decision curve analysis

Effect of caffeine on hyperoxic lung injury of premature rats and its relationship with p38 motigen-activated protein kinase signal pathway

Objective To study the effect of caffeine on hyperoxic lung injury of premature rats and its relationship with p38 motigen-activated protein kinase(MAPK) signal pathway. Methods Sixty Wistar premature rats were divided into 4 groups(n=15) according to the random number table: air + normal saline group(A+ N group), air + caffeine group(A+ C group), hyperoxia + normal saline group(H+ N group), and hyperoxia + caffeine group(H+ C group). Among them, H+ N group and H+ C group were continually exposed to hyperoxia(oxygen concentration was 60%~70%). For A+ C group and H+ C group, the premature rats were injected with caffeine of 29 mg/(kg·d) into their peritoneal cavities every day after birth.For A+ N group and H+ N group, the premature rats were injected with normal saline of the same volume into their peritoneal cavities.In each group, the lung tissues of 5 premature rats were randomly selected on the third, seventh and fourteenth day respectively.The pathological changes of lung tissue, radiated alveolar count(RAC) and collagen content in lung tissue were observed under a light microscope.The wet/dry ratio(W/D) was measured.Two-step immunohistochemistry was used to detect the distribution of p38MAPK in lung tissue.The content of phosphorylated p38MAPK(p-p38MAPK) protein was detected by western blot. Results Compared with the air groups, the lung tissues of premature rats in high oxygen exposure groups showed different degree of inflammatory changes on the third, seventh, and fourteenth day.The changes were more obvious with the prolonged exposure to hyperoxia.Pulmonary fibrosis was visible on the fourteenth day, which was improved after caffeine intervention.The RAC value of premature rats in hyperoxia exposure groups was significantly lower than that in air-exposure groups(P<0.05), and the W/D ratio and collagen content in lung tissue increased significantly(P<0.05), which were improved after caffeine intervention(P<0.05). The results of two-step immunohistochemistry showed that the number of p-p38MAPK positive cells in the lung tissue of premature rats in hyperoxia exposure groups increased and widely distributed, but decreased after caffeine intervention.The results of western blot showed that the content of p-p38MAPK protein in lung tissue of premature rats in hyperoxia exposure groups was significantly higher than that of air groups(P<0.05), but it decreased after caffeine intervention(P<0.05). Conclusion Hyperoxia can promote the formation of pulmonary fibrosis by activating p38MAPK signal pathway.Caffeine can interdict the expression of p38MAPK to alleviate the fibrosis of lung tissue exposed to hyperoxia and thus protects the lung tissue. Key words: Hyperoxia; Lung injury; Caffeine; p38 motigen-activated protein kinase; Premature rats

Parametric evaluation of a heat pipe-radiator assembly for nuclear space power systems

The research and technological development towards compact energy conversion systems for space applications allow the emergence of new mission possibilities, especially those directed for deep space explorations. Besides the final efficiency, the most crucial factor of an energy conversion system for nuclear propulsion purposes is the total mass and size of the system. Considering the Closed Brayton Cycle (CBC) as the energy conversion system for a nuclear power system, a numerical analysis was carried out in order to predict the thermal performance of cold side of the system (i.e., heat pipes and radiator) for initial design purposes. The complete space heat pipe-radiator array was discretized in control volumes where a variation of geometrical parameters was included, resulting in a stepped trapezoidal-shaped radiator (RAD) as output. The heat capacity was limited by the geometry of each panel section, being its heat pipe modeled to fit the given geometry and verified against operational limits. The proposed design-based model considered a physical and thermal coupling with temperature drops along the heat pipe (HP) axial direction, the radiator panel surface, and the cold heat exchanger duct, providing reasonable global parameters to aid the design considering mass and size optimization of a heat pipe-radiator assembly. The number of heat pipes and the total heat pipe-radiator assembly mass and length were evaluated for different heat pipe spacing, heat transfer rate, cold heat exchanger (CHE) inlet temperatures, and radiation shield shadow angles. It was observed a point of minimum HP-RAD mass and length when the heat pipe spacing and CHE inlet temperature are varied, for a given heat transfer rate and shadow angle.

Grafen Tabanlı Nanoakışkanların Araç Radyatörü Soğutma Performansı Üzerindeki Etkisinin Deneysel Analizi

Bu deneysel çalışmada, araç radyatörüne ait soğutma performansı saf su, grafen oksit (GO)-saf su ve grafen nano ribon (GNR) -saf su nanoakışkanları kullanılarak incelenmiştir. Deneyler 3 farklı akışkan giriş sıcaklığı (36, 40 ve 44 oC) ve 4 farklı debi (0.6, 0.7, 0.8 ve 0.9 m3 h-1) kullanılarak gerçekleştirilmiştir. Deneysel veriler kullanılarak nanoakışkanlara ait toplam ısı transferi katsayısı değerleri hesaplanmıştır. Araç radyatörü dikdörtgen kesitli bir kanal ile sabit hızda hava kullanılarak soğutulmuştur. Soğutma performansındaki artış, elde edilen deneysel verilere göre saf su ve nanoakışkanlar için toplam ısı transfer katsayıları karşılaştırılarak belirlenmiştir. U değerlerindeki en yüksek ortalama artış oranlarının %0.01 GO-saf su, %0.02 GO-saf su ve %0.01 GNR-saf su nanoakışkanları için sırasıyla %6.9, %32 ve için %18.9 oldukları sonucuna varılmıştır.

Design and Implementation of Remote RFI Monitoring System for Ghana Radio Telescope Observatory-Nkutunse

Radio telescope receivers are sensitive instruments designed to detect very weak signals radiating from astronomical sources. These signals travel several light years and are sometimes drain by the interference of man-made and terrestrials RFI’s. This work aims at the design of a cost-effective Radio Frequency Interference Monitoring System (RFIMS) for the Ghana Radio Astronomy Observatory at Nkutunse. The design of automated RFIMS was constructed with a log-periodic antenna for receiving the electric field being radiated, Low Noise Amplifier (LNA) to amplify the weak signals for detectability, an attenuator to control the high power interfering signals, a filter to pass frequency of interest and a spectrum analyzer as backend. Ideally, telescopes are supposed to be sited at a radio quiet environment. The implementation is to continually monitor the radio space for potential interference at the telescope site for remedial actions since it has become a global candidate site by location and necessitation.