Mapping the relationship between the subjective response of jurors to fan blade parameters

Thesis (MEng)--Stellenbosch University, 2020.ENGLISH ABSTRACT: The noise generated by computer cooling fans is known to be a factor which may cause discomfort in the workplace. Aerodynamic noise caused by fan blades has been identified to be a significant factor which contributes largely to noise emission by fans. Fan parameters used in the design of fan blades are known to affect noise emission levels significantly. Considerations made for fan noise are known to be centred around taking unweighted and A-weighted sound pressure readings, with fan designs often being designed to limit sound pressure levels. The analysis made towards the unweighted and A-weighted sound pressure levels in the temporal and frequency domain alone is known to sufficiently define objective measures for fan noise. It is of interest to consider whether the subjective evaluation of noise made by jurors can also be accounted for. The presented work is focused on identifying the feasibility of mapping the relationship between fan blade parameters to the subjective response of jurors, using the interim step of psychoacoustic analysis to make predictions for an expected level of annoyance towards fan noise emissions. Three blade parameters were selected for investigation, consisting out of blade chord, blade angle and sweep; these are considered to have significant effects on noise emissions produced by fan blades. Fifteen prototype models with varied blade parameters were created to investigate the effect which blade parameters have on the subjective evaluation of noise. Prototype models were created by 3D scanning and recreating a reference commercial fan, altering its blade parameters by using mesh morphing techniques. Jury evaluation tests were used to collect data towards the perceived annoyance for fan noise using a forced pairwise comparison test, and a bipolar semantic differential test. The jury tests were used to obtain a ranking for prototype models, giving a relative measure of perceived preference, and also a description for noise, as experienced by jurors. Statistical analysis methods were used to fit simple, well-defined regression models, which were used to learn about the interaction effects present. One model, deemed adequate for making predictions on jury preferences, was selected and used for optimisation purposes. This model was optimised to determine the best expected performance, for a specific set of blade parameters. A final model using optimised blade parameters was 3D printed and used as a validation set to evaluate for the model. The optimised model was ranked 3rd in the final, forced pairwise comparison test, where 20 jurors were asked to partake in the test. The presented work determined the relationship between blade parameters, psychoacoustic metrics and data obtained from subjective jury test results to determine the feasibility of determining jury preference from the parameters of a fan blade alone.AFRIKAANSE OPSOMMING: Die geraas wat 'n rekenaar se waaier genereer, is 'n faktor wat ongemak in die werkplek kan veroorsaak. En hoe harder die waaier werk, hoe groter is die ongewenste geraasvlakke dikwels ook. Aërodinamiese geraas, wat deur waaierlemme veroorsaak word, is geïdentifiseer as 'n belangrike faktor wat grootliks bydra tot die geraas wat 'n waaier vrystel. Die waaierparameters wat in die ontwerp van waaierlemme gebruik word, is bekend daarvoor dat dit 'n beduidende invloed het op die vlak van geraas wat gemaak word. Dit is bekend dat die oorwegings vir waaiergeraas, op die neem van ongeweegde en A-geweegde klankdruklesings berus, met waaiers wat dikwels ontwerp word om klankdrukvlakke te beperk. Die ontleding wat van die ongeweegde en Ageweegde klankdrukvlak gemaak word, in die tydelike en frekwensie-domein alleen, is bekend daarvoor dat dit op voldoende wyse objektiewe maatstawwe vir waaiergeraas omskryf. 'n Vraag van belang is egter of die subjektiewe evaluering van geraas deur 'n persoon wat dit beoordeel, ook verantwoord kan word. Die werk wat hier aangebied word, fokus daarop om te bepaal hoe haalbaar dit is om die verband tussen die parameters van waaierlemme en die subjektiewe respons van beoordelaars te karteer, deur middel van psigo-akoestiese analise as tussenstap te gebruik om voorspellings te maak oor die irritasievlak wat 'n waaier se geraas na verwagting sal veroorsaak. Vir die ondersoek is drie parameters van 'n waaierlem geselekteer: naamlik die koord, die hoek en die swiep van die lem, wat geïdentifiseer is as elemente wat 'n aansienlike invloed het op die geraas wat waaierlemme maak. Vyftien prototipiese modelle, met verskillende lemparameters, is geskep om die effek te ondersoek wat lemparameters het op die subjektiewe evaluering van geraasuitset, soos waargeneem deur die beoordelaars. Die prototipiese modelle is geskep deur 3D-skandering en die herskepping van 'n kommersiële waaier as verwysing deur sy lemparameters, deur middel van sogenaamde mesh morphing-tegnieke te verander. Tweeledige beoordelaarsevalueringstoetse is gebruik om data te versamel oor die werklik waargenome ergernis weens waaiergeraas: naamlik, 'n gedwonge paargewys-vergelykende toets en 'n bipolere semantiese differensiaaltoets. Die beoordelaarstoetse is gebruik om 'n rangorde vir die prototipiese modelle te bepaal, deur 'n relatiewe maatstaf van waargenome voorkeur te gee, asook 'n beskrywing van die geraas, soos deur die beoordelaars ervaar. Statistiese ontledingsmetodes is daarna gebruik om 'n eenvoudige, goed gede niëerde regressiemodel op die data toe te pas, en die model is gebruik om meer te wete te kom oor die wisselwerking tussen lemparameters, psigo-akoestiese maatstawwe en die subjektiewe reaksie van beoordelaars. Die sensitiwiteit vir modelle is bepaal en 'n model, wat met behulp van lemparameters, voorspellings oor beoordelaarsvoorkeur kon maak, is geselekteer en geoptimaliseer vir 'n stel lemparameters wat na verwagting die beste prestasie sou gee. 'n Finale model met lemparameters wat uit die optimalisering voortgespruit het, is 3D gedruk en as 'n valideringstel gebruik om die model te evalueer. In die finale, gedwonge paargewys-vergelykende toets, waarin 20 beoordelaars gevra is om aan die toets deel te neem, is die optimeerde model derde geplaas. Die werk wat hier aangebied word, het die verband bepaal tussen lemparameters, psigoakoestiese maatstawwe en data, wat uit subjektiewe beoordelaarstoetse verkry is, om te bepaal hoe haalbaar dit is om beoordelaarsvoorkeur op grond van die parameters van 'n waaierlem alleenlik, te bepaal.Master

The Prismatic Effect on Stereoacuity in Intermittent Exotropia

PURPOSE: To evaluate the effect of acrylic refractive prism and Fresnel membrane prism on stereoacuity in intermittent exotropia. MATERIALS AND METHODS: Stereoacuities of fifty-two patients (mean age, 12.4 years; range 6 to 45 years) with intermittent exotropia were measured using the Titmus and TNO stereotests, while they wore prisms of varying power on nonfixating eye or evenly on each eye. RESULTS: Stereoacuities were significantly reduced with increasing prism power for both prisms, ranging from 8 to 25 prism dipotres. The effects on stereoacuity in single acrylic prism and single Fresnel prism were similar, whereas spilt Fresnel prisms reduced stereoacuity more than spilt acrylic prisms. Spilt prisms were found to have much less effect on stereoacuity than single prisms for both acrylic and Fresnel prisms. CONCLUSION: The use of acrylic refractive prism shared evenly on each eye would be optimal method to minimize the reduction of stereoacuity during the prismatic therapy for intermittent exotropia.ope

Genome-edited HEADING DATE 3a knockout enhances leaf production in Perilla frutescens

Environmental cues regulate the transition of many plants from vegetative to flowering development. Day length, or photoperiod, is one cue that synchronizes flowering by changing seasons. Consequently, the molecular mechanism of flowering control is prominent in Arabidopsis and rice, where essential genes like FLOWERING LOCUS T (FT) homolog, HEADING DATE 3a (Hd3a), have been connected to flowering regulation. Perilla is a nutrient-rich leaf vegetable, and the flowering mechanism remains largely elusive. We identified flowering-related genes under short-day conditions using RNA sequencing to develop an enhanced leaf production trait using the flowering mechanism in the perilla. Initially, an Hd3a-like gene was cloned from the perilla and defined as PfHd3a. Furthermore, PfHd3a is highly rhythmically expressed in mature leaves under short-day and long-day conditions. Ectopic expression of PfHd3a in Atft-1 mutant plants has been shown to complement Arabidopsis FT function, resulting in early flowering. In addition, our genetic approaches revealed that overexpression of PfHd3a in perilla caused early flowering. In contrast, the CRISPR/Cas9 generated PfHd3a-mutant perilla showed significantly late flowering, resulting in approximately 50% leaf production enhancement compared to the control. Our results suggest that PfHd3a plays a vital role in regulating flowering in the perilla and is a potential target for molecular breeding in the perilla

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

CRYPTO BASED EPC C1G2 UHF (860 MHz-960 MHz) PASSIVE RFID TAG CHIP

The metal-ferroelectric-metal (MFM) capacitor in ferroelectric random access memory (FeRAM) security embedded RFID chip is used not only in the memory cell region but also used in the analog and digital circuit area for low cost capacitance device and high security algorithm. MFM based security FeRAM braces for a wide range of security threats such as reverse engineering, cloning, and tampering. High security performance solution of on-chip FeRAM based register key is implemented to prepare against security attacking. RF transferring sensitivity properties with MFM capacitor are almost same or better than that with poly-insulator-poly (PIP) capacitor and metal-insulator-metal (MIM), and MOS capacitor. The measured power consumption of FeRAM embedded RFID chip without crypto processor engine is about 10 W with the write sensitivity of -18dBm.

Cannabinoid Receptor Type 1 Protects Nigrostriatal Dopaminergic Neurons Against Mptp Neurotoxicity By Inhibiting Microglial Activation

This study examined whether the cannabinoid receptor type 1 (CB1) receptor contributes to the survival of nigrostriatal dopaminergic (DA) neurons in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson\u27s disease. MPTP induced significant loss of nigrostriatal DA neurons and microglial activation in the substantia nigra (SN), visualized with tyrosine hydroxylase or macrophage Ag complex-1 immunohistochemistry. Real-time PCR, ELISA, Western blotting, and immunohistochemistry disclosed upregulation of proinflammatory cytokines, activation of microglial NADPH oxidase, and subsequent reactive oxygen species production and oxidative damage of DNA and proteins in MPTP-treated SN, resulting in degeneration of DA neurons. Conversely, treatment with nonselective cannabinoid receptor agonists (WIN55,212-2 and HU210) led to increased survival of DA neurons in the SN, their fibers and dopamine levels in the striatum, and improved motor function. This neuroprotection by cannabinoids was accompanied by suppression of NADPH oxidase reactive oxygen species production and reduced expression of proinflammatory cytokines from activated microglia. Interestingly, cannabinoids protected DA neurons against 1-methyl-4-phenyl-pyridinium neurotoxicity in cocultures of mesencephalic neurons and microglia, but not in neuron-enriched mesencephalic cultures devoid of microglia. The observed neuroprotection and inhibition of microglial activation were reversed upon treatment with CB1 receptor selective antagonists AM251 and/or SR14,716A, confirming the involvement of the CB1 receptor. The present in vivo and in vitro findings clearly indicate that the CB1 receptor possesses anti-inflammatory properties and inhibits microglia-mediated oxidative stress. Our results collectively suggest that the cannabinoid system is beneficial for the treatment of Parkinson\u27s disease and other disorders associated with neuroinflammation and microglia-derived oxidative damage. Copyright © 2011 by The American Association of Immunologists, Inc

Fabrication of Bulk Amorphous Alloy Sheets by Strip Casting

A study has been made to fabricate the bulk amorphous alloy sheets by strip casting. Simulation of the solidification behavior of the Zr-base amorphous forming alloy during strip casting shows that fast enough cooling rate can be achieved by strip casting to form amorphous structure through the thickness of sheet. Two alloys with different glass forming abilities were subjected to actual strip casting, which shows that both Zr-base alloy with high GFA and Cu-base alloy with much less GFA can be strip cast forming amorphous structure. The results indicate that the strip casting is a viable process for continuous fabrication of sheets of bulk amorphous alloys with a wide range of critical cooling rates.close