Development of Energy Harvesting System Using Rotation Mechanism of a Revolving Door

Conventional Energy sources are depleting with time. There is a dire need to find new sources of energy. The new methods of energy should be able to replace dwindling sources of energy. Energy Harvesting is one such method where ambient energy from environment is converted into useful energy. Unfortunately, there is not enough work done on energy harvesters. The purpose of this project is to show that the abundant ambient energy in the surroundings can be utilized to generate electricity. In this project, the energy used to open a revolving door is being converted into Electrical Energy. Accordingly, a Revolving Door prototype was designed, fabricated and tested. The test results are used to calculate the amount of energy being harvested on one push of the door. This prototype can be further optimized in order to generate more Electrical Energy

Low Power Switched Capacitor DC-DC Converters for Low Power Transceiver Applications

DC-DC converters, also known as switching voltage regulators, are one of the main components of a power management unit. Their main role is to provide a constant, smooth output voltage to power the electronic devices. Recent miniaturi-zation trend of electronics circuitry has led to the need for smaller and high-efficient DC-DC converters in current and future applications. This thesis presents a Switched Capacitor (SC) based DC-DC converter, which can directly operate at input voltage of 4.2V on 45nm CMOS process. Currently, most of the DC-DC converters on 45nm are not able to operate at such high volt-ages. Moreover, SC architecture has resulted in smaller size of converter com-pared with LC type DC-DC converters. The design uses three SC topologies, which include two novel SC topologies of 2/5 and 2/7. Devices break down conditions have been overcome by implement-ing some of the MOS switches in cascoded structures. The converter structure uses eight phase interleaving approach to reduce output ripple to as low as 25mV level. In addition to the main SC structure, a four-stage differential ring oscillator is de-signed for providing quadrature clock signals to the SC topologies. Clock genera-tor can be enabled/disabled from outside the chip, through an enable (EN) pin. For instance, the EN pin can be used for regulating the output voltage in Pulse Fre-quency Modulation (PFM) feedback approach. /Kir1

Cycling vs Running – An in-depth analysis

This short letter to the editor provides ideas about exercises that improves cardiovascular fitness

Techno-economic feasibility of combine harvester (class denominator

ABSTRACT Techno-economic feasibility of using combine harvester (Class Denominator) was carried out by determining harvesting losses, timeliness of harvesting, field capacity, fuel consumption, noise and dust pollution, frequency of repair/maintenance and operating cost of the machine. The results indicated that combine had an average harvesting losses of about 1.25% of wheat yield. Grain breakage losses (5.7%) were bit higher. The machine was able to harvest 2.5 to 3.0 acres in an hour. The fuel consumption of the combine was found to be 15 L of diesel per acre. As the machine was not equipped with a proper cab, dust and noise pollution posed threat to the operator's health. The machine needed only two to three persons for its operation and costs about Rs 860/acre to the user. The combine is an efficient, economical, labor and time saving machine but its initial cost is quite high. To promote this high cost technology, it is suggested that the District Governments of present set up should make arrangements at Tehsil Council level to provide combine to the farmers on rental basis

Oštećenja u aluminiju proizvedena zračenjem iz CO2 i Nd:YAG lasera

The change in the electrical properties of pure aluminium (Al 99.999%) after exposure to CO2 (energy = 2.5 J/pulse, wavelength = 10.6 µm, pulse duration = 200 nsec) and Nd:YAG (energy = 10 mJ/pulse, wavelength = 1.06 µm and pulse duration = 12 nsec) laser radiation is investigated. The samples were exposed to laser radiations for different numbers of pulses. The change in electrical characteristics of Al is studied under different ambient conditions, after irradiating the samples in air, vacuum and hydrogen at different pressures. After exposure, the electrical conductivity of Al is measured by the four probe method. The electrical conductivity decreases with increasing number of pulses. The damage in air and in hydrogen is more pronounced than in vacuum which can be attributed to collisionnal sputtering of Al by plasma ions of air molecules and hydrogen, respectively. The change in the conductivity in hydrogen is pressure-dependent. Some theoretical considerations are also made, e.g. the phonon speed in Al during the photon interaction, minimal melting and evaporation energy per volume, damage threshold energy, penetration depth, the mass of heated volume and average temperature rise at the Al surface during laser irradiation.Proučavamo promjene električnih svojstava čistog aluminija (Al 99.999%) nakon obasjavanja CO2 (energija = 2.5 J/puls, valna duljina = 10.6 µm, trajanje pulsa = 200 nsec) i Nd:YAG (energija = 10 mJ/puls, valna duljina = 1.06 µm, trajanje pulsa = 12 nsec) laserima. Uzorci su izloženi različitim brojevima pulseva. Proučavali smo promjene električne vodljivosti Al s uzorcima u zraku, vakuumu i u vodiku. Nakon obasjavanja mjerili smo električnu vodljivost metodom četiriju spojišta. Električna se vodljivost smanjuje nakon povećanog broja pulseva. Oštećenja u zraku i vodiku veća su nego u vakuumu, što se pripisuje sudarnom rasprašivanju Al ionima molekula zraka odnosno vodika u plazmi. Promjena vodljivosti uzoraka obasjanih u vodiku ovisna je o tlaku. Razmotrili smo neke teorijske rezultate, npr. fononsku brzinu u Al tijekom obasjavanja, minimalnu energiju taljenja i isparavanja po jedinici volumena, energijski prag oštećenja, dubinu prodiranja, masu zagrijanog volumena i prosječno povećanje temperature površine Al tijekom obasjavanja

Approaches to Different Learning Styles in Undergraduate Medical Students of Al-Tibri Medical College Karachi

Objectives: The purpose of this study was to evaluate the different styles of learning preferred by undergraduate medical students from 1st to 5th year of Al-Tibri Medical College KarachiMethodology: This was a cross sectional observational study carried out on the undergraduate medical students of Al-Tibri Medical College Karachi from 1st year to 5th year for a period of six months. The sample consisted of 498 participants, distributed across the various academic years: 101 from the first year, 96 from the second year, 101 from the third year, 104 from the fourth year, and 96 from the fifth year. For collecting data, a self-administered and pre-tested questionnaire of VARK learning styles was distributed amongst students. The analysis of data was done using SPSS version 23.Results: From 498 undergraduate medical students included, mean age was 20.93 ± 2.27 years. Mean score for visual learning style was 2.75 ± 2.5, auditory was 3.4 ± 2.1, reading / writing was 3.9 ± 2.8 and kinesthetic was 4.75 ± 3.2. 56 % of 1st year students opted for uni-modal while 44 % multi-modal learning style. 51 % of 2nd year students preferred uni-modal while 49 % multi-modal learning style. 52 % of 3rd year students chose uni-modal while 48 % multi-modal learning style. 50 % of 4th year students picked uni-modal and multi-modal learning style each. 44 % of 5th year students opted for uni-modal while 56 % multi-modal learning style.Conclusion: Majority of students approached learning using kinesthetic style followed by reading / writing. A multi-modal mode of learning was preferred where a combination of either of VARK’s learning styles were put into practice for attaining and acquiring the best possible knowledge

Oštećenja u aluminiju proizvedena zračenjem iz CO2 i Nd:YAG lasera

The change in the electrical properties of pure aluminium (Al 99.999%) after exposure to CO2 (energy = 2.5 J/pulse, wavelength = 10.6 µm, pulse duration = 200 nsec) and Nd:YAG (energy = 10 mJ/pulse, wavelength = 1.06 µm and pulse duration = 12 nsec) laser radiation is investigated. The samples were exposed to laser radiations for different numbers of pulses. The change in electrical characteristics of Al is studied under different ambient conditions, after irradiating the samples in air, vacuum and hydrogen at different pressures. After exposure, the electrical conductivity of Al is measured by the four probe method. The electrical conductivity decreases with increasing number of pulses. The damage in air and in hydrogen is more pronounced than in vacuum which can be attributed to collisionnal sputtering of Al by plasma ions of air molecules and hydrogen, respectively. The change in the conductivity in hydrogen is pressure-dependent. Some theoretical considerations are also made, e.g. the phonon speed in Al during the photon interaction, minimal melting and evaporation energy per volume, damage threshold energy, penetration depth, the mass of heated volume and average temperature rise at the Al surface during laser irradiation.Proučavamo promjene električnih svojstava čistog aluminija (Al 99.999%) nakon obasjavanja CO2 (energija = 2.5 J/puls, valna duljina = 10.6 µm, trajanje pulsa = 200 nsec) i Nd:YAG (energija = 10 mJ/puls, valna duljina = 1.06 µm, trajanje pulsa = 12 nsec) laserima. Uzorci su izloženi različitim brojevima pulseva. Proučavali smo promjene električne vodljivosti Al s uzorcima u zraku, vakuumu i u vodiku. Nakon obasjavanja mjerili smo električnu vodljivost metodom četiriju spojišta. Električna se vodljivost smanjuje nakon povećanog broja pulseva. Oštećenja u zraku i vodiku veća su nego u vakuumu, što se pripisuje sudarnom rasprašivanju Al ionima molekula zraka odnosno vodika u plazmi. Promjena vodljivosti uzoraka obasjanih u vodiku ovisna je o tlaku. Razmotrili smo neke teorijske rezultate, npr. fononsku brzinu u Al tijekom obasjavanja, minimalnu energiju taljenja i isparavanja po jedinici volumena, energijski prag oštećenja, dubinu prodiranja, masu zagrijanog volumena i prosječno povećanje temperature površine Al tijekom obasjavanja

Analysis of Growing Tumor on the Flow Velocity of Cerebrospinal Fluid in Human Brain Using Computational Modeling and Fluid-Structure Interaction

Cerebrospinal fluid (CSF) plays a pivotal role in normal functioning of Brain. Intracranial compartments such as blood, brain and CSF are incompressible in nature. Therefore, if a volume imbalance in one of the aforenoted compartments is observed, the other reaches out to maintain net change to zero. Whereas, CSF has higher compliance over long term. However, if the CSF flow is obstructed in the ventricles, this compliance may get exhausted early. Brain tumor on the other hand poses a similar challenge towards destabilization of CSF flow by compressing any section of ventricles thereby ensuing obstruction. To avoid invasive procedures to study effects of tumor on CSF flow, numerical-based methods such as Finite element modeling (FEM) are used which provide excellent description of underlying pathological interaction. A 3D fluid-structure interaction (FSI) model is developed to study the effect of tumor growth on the flow of cerebrospinal fluid in ventricle system. The FSI model encapsulates all the physiological parameters which may be necessary in analyzing intraventricular CSF flow behavior. Findings of the model show that brain tumor affects CSF flow parameters by deforming the walls of ventricles in this case accompanied by a mean rise of 74.23% in CSF flow velocity and considerable deformation on the walls of ventricles

Knowledge, attitude and perception survey of doctors regarding antibiotic use and resistance in Karachi, Pakistan

Objective: To establish a better understanding of physicians\u27 knowledge and beliefs, and to compare distinctions in knowledge, attitude and perception of junior and senior doctors regarding rational use of antibiotics.Methods: The cross-sectional study was conducted at a tertiary care hospital in Karachi, from June 1 to July 31, 2016, and comprised senior and junior doctors. A 26-item questionnaire divided in three sections was used to test knowledge, attitude and perception of the subjects regarding rational use of antibiotics. Data was analysed using SPSS 23.Results: Of the 200 subjects, 132(66%) were senior doctors; 68(34%) were junior; 116(58%) were females; 84(42%) were males; and the highest number of respondents were from General Medicine 65(32.5%). While 182(91%) doctors realised that antibiotic resistance was a pressing issue, only 131(65.5%) felt confident about their prescriptions and 94(47%) admitted that they over-prescribed antibiotics. Among young physicians, 13(19.1%) believed that antibiotics did not cause side effects even when prescribed unnecesarily. Also, 47(69.1%) junior doctors felt that patients\u27 demands influenced their prescriptions compared to 66(50%) senior doctors (p=0.01).Conclusion: Although physicians were found to be knowledgeable about rational use of antibiotics, there were gaps in knowledge and perception

Yield performance with heritability measurements of half sib families obtained from maize variety Azam

This study evaluated the performance of 64 half sib families (HSF) derived from “Azam” variety of maize using partially balanced lattice square design with two replications. Data were recorded on grain yield and other agronomic traits. Observations showed difference in half-sib families for studied traits. Among the 64 half-sib families, minimum days to 50% tasseling (51 days) were observed for HS-49 while maximum (57 days) for HS-63. Minimum days to 50% silking (56 days) were counted for HS-6 while maximum (63 days) for HS-23. Minimum days to 50% anthesis (55 days) were counted for HS-1 and HS-6 while maximum (62 days) for HS-23. Similarly, minimum ASI (-2 days) were observed in HS-1, HS-15, HS-16, HS-28 and HS-63 while maximum (2 days) in HS-48. Minimum (60 cm) ear height was recorded for HS-11 and maximum (93.5 cm) for HS-28. Minimum fresh ear weight (1.3 kg) was weighted for HS-17 while maximum (3.2 kg) for HS-21. Grain moisture was recorded minimum (19.35 %) for HS-19 and maximum (31.25%) for HS-2. HS-42 showed minimum (28 g) 100 kernel weight while HS-5 showed maximum (47 g). Grain yield was minimum (2323 kg ha-1) for HS-17 and maximum (5742 kg ha-1) for HS-21. Maximum heritability estimate (0.92) was recorded for fresh ear weight, while minimum (0.41) was observed for ear height