The Physicist's Guide to the Orchestra

An experimental study of strings, woodwinds (organ pipe, flute, clarinet, saxophone and recorder), and the voice was undertaken to illustrate the basic principles of sound production in music instruments. The setup used is simple and consists of common laboratory equipment. Although the canonical examples (standing wave on a string, in an open and closed pipe) are easily reproduced, they fail to explain the majority of the measurements. The reasons for these deviations are outlined and discussed.Comment: 11 pages, 10 figures (jpg files). Submitted to European Journal of Physic

Modelling vertical uniform contact stress of heavy vehicle tyres

The field of tyre dynamics is a relatively new, but highly complex field of engineering. The testing and modelling of various tyres in order to determine stress distributions of tyres on the road surface, under varying conditions, remains a relevant and important field of study. The information from these studies are essential to understanding vehicle dynamics as the small contact patches between the vehicle tyres and road surface is the only area of interaction between the entire vehicle and the road surface. The contact stress data is also essential in the calculation of road wear characteristics of tyres and vehicles. Different models exist to estimate the contact stress between the tyre and road surface, but most contain assumptions that limit their applicability to a small set of tyres under very specific load cases. This paper considers the development of mathematical models that are used to estimate the vertical uniform contact stress for three types of heavy vehicle tyres. The three tyres studied are 315/80 R22.5, 385/65 R22.5 and 425/65 R22.5 tyres. The models have been developed through the use of tyre testing data obtained from the Stress-In-Motion (SIM) system. It was found that 4th order polynomials provided the most accurate stress results over the selected operating range of 25 kN to 45 kN which is the typical load range for heavy vehicle tyres due to legal axle load limits. The polynomial formulas require only the tyre inflation pressure and vertical tyre load as inputs, in order to estimate the vertical uniform contact stress. The models developed correlate well with the test data and showing an average absolute error of less than 2 %.Paper presented at the 35th Annual Southern African Transport Conference 4-7 July 2016 "Transport ? a catalyst for socio-economic growth and development opportunities to improve quality of life", CSIR International Convention Centre, Pretoria, South Africa.The Minister of Transport, South AfricaTransportation Research Board of the US

Assessing the roll stability of heavy vehicles in South Africa

In South Africa there are approximately 12.5 truck-crash-related fatalities per 100 million kilometres travelled. This is between 4 and 10 times higher than a number of European countries such as Denmark, France, Germany and Switzerland and many of these crashes involve heavy vehicle rollover. The regulations in the National Road Traffic Act of South Africa that govern heavy vehicle design do not directly address the roll stability of heavy vehicles. The internationally accepted method of regulating roll stability is by means of a static rollover threshold (SRT) assessment or test, to determine the maximum lateral acceleration that a vehicle can withstand before rolling over. The SRT is determined by physical testing, or through multibody dynamics simulation; however, both of these approaches are costly and time-consuming. This paper considers various simplified tools to estimate the SRT of articulated heavy vehicles, and compares the results to SRT values determined using multibody dynamics simulation. The simplified tool as described by the New Zealand Land Transport Rule was identified as the most viable technique to potentially regulate the roll stability of heavy vehicles in South Africa.Paper presented at the 35th Annual Southern African Transport Conference 4-7 July 2016 "Transport ? a catalyst for socio-economic growth and development opportunities to improve quality of life", CSIR International Convention Centre, Pretoria, South Africa.The Minister of Transport, South AfricaTransportation Research Board of the US

A pro-forma design for car-carriers : low-speed performance-based standards

The Australian performance-based standards (PBS) scheme is being evaluated in South Africa as an alternative means of regulating heavy vehicles, allowing for a relaxation of length and mass limits. This has proven to provide economic benefits while improving vehicle safety and emissions. Within the PBS scheme, the vehicle is assessed using twelve performance standards which can be grouped together as low-speed directional, high-speed directional, stability and longitudinal performance measures. Compliance with these standards requires expensive and time-intensive computer simulations; a hurdle to the car-carrier industry in particular. We propose a pro-forma car-carrier design in which limits on the most important car-carrier parameters are defined to ensure compliance with the low-speed PBS. It is proposed that new car-carrier designs complying with this semi-prescriptive pro-forma design be exempted from full PBS assessment in the South African PBS project. In this paper the parametric sensitivity of the low-speed performance standards was assessed, and suitable limits on these parameters were found. Tests were carried out on hypothetical designs within these limits. It was found that each of the 10 000 vehicle configurations generated within the constraints of the pro-forma design met the Level 1 requirements of the low-speed PBS. Future work will ensure compliance with the full set of twelve performance standards. It is estimated that the pro-forma approach as compared to doing full assessments would save the South African car-carrier industry an estimated R1,200,000 in one year.Paper presented at the 34th Annual Southern African Transport Conference 6-9 July 2015 "Working Together to Deliver - Sakha Sonke", CSIR International Convention Centre, Pretoria, South Africa.The Minister of Transport, South AfricaTransportation Research Board of the US

Phonophoresis in Physiotherapy: Mechanisms, Applications, and Emerging Trends for Enhanced Drug Delivery and Therapeutic Efficacy

Phonophoresis, a widely utilized treatment in physiotherapy, combines topically applied gel or cream-based medications with ultrasonic therapy to enhance percutaneous absorption of pharmacological agents. The procedure employs ultrasound frequencies of 0.7 to 1.1 MHz with intensities ranging from 0.0 to 3.0 Watts per cm². Indications for phonophoresis span various inflammatory, deformative, dermatological, and rheumatic/neurological conditions. Recent studies suggest its clinical efficacy in pain relief and improved function, especially in conditions like lateral epicondylitis and osteoarthritis. The mechanism of action involves both thermal and non-thermal effects, with cavitation playing a key role in enhancing transdermal transport. Phonophoresis offers a non-invasive alternative for drug delivery, bypassing hepatic metabolism and minimizing systemic side effects. Various medicinal gels, particularly diclofenac, are used for transdermal drug delivery through phonophoresis. Low frequency phonophoresis has gained attention for enhancing transdermal transport, especially for macromolecules. Its applications extend beyond physiotherapy to include ocular drug delivery, nail therapy, gene therapy, and sports sciences. Clinical studies demonstrate the effectiveness of phonophoresis in conditions like anterior knee pain, tuberculous lymphadenitis, acute low back pain, and latent myofascial trigger points. Dosage considerations emphasize optimizing thermal effects without causing tissue damage. Studies highlight the potential of phonophoresis in relieving pain and improving function, particularly in knee osteoarthritis. Additionally, phonophoresis with Phyllanthus amarus nanoparticle gel shows promise in reducing pain and enhancing functional capacity in symptomatic knee osteoarthritis. In summary, phonophoresis stands as a valuable modality in physiotherapy, showcasing diverse applications and demonstrating clinical efficacy in various musculoskeletal and inflammatory conditions. Further research is warranted to explore its full potential and optimize treatment protocols

Intonation and Compensation of Fretted String Instruments

In this paper we present mathematical and physical models to be used in the analysis of the problem of intonation of musical instruments such as guitars, mandolins and the like, i.e., we study how to improve the tuning on these instruments. This analysis begins by designing the placement of frets on the fingerboard according to mathematical rules and the assumption of an ideal string, but becomes more complicated when one includes the effects of deformation of the string and inharmonicity due to other string characteristics. As a consequence of these factors, perfect intonation of all the notes on the instrument can never be achieved, but complex compensation procedures are introduced and studied to minimize the problem. To test the validity of these compensation procedures, we have performed extensive measurements using standard monochord sonometers and other basic acoustical devices, confirming the correctness of our theoretical models. In particular, these experimental activities can be easily integrated into standard acoustics courses and labs, and can become a more advanced version of basic experiments with monochords and sonometers.Comment: Improved version, with minor changes. 25 pages, including 6 figures and 2 tables. Accepted for publication in the American Journal of Physics (AJP

Design and Development of Machine to Remove Outer Cover of Groundnut

In republic of India, most of the land is used for agricultural purpose that produces semi-finished merchandise or product. Groundnut is additionally one in every of the agriculture semi-finished product. Groundnut is grownup on tiny scale farmers in developing countries like Republic of India. Lack of groundnut process machines, particularly groundnut worker is major downside of groundnut production. In early stages folks accustomed decoct groundnut manually. The output obtained was terribly low by this methodology. The analysis work for style, fabricate and performance of groundnut worker systematically of feed hopper with a rate of flow, management devices, firing unit separating unit and blower system. The machine is supported by a ½ HP motor operational on 720rpm. Falling pods from hopper are stuck by rotating drum, the chaffs are blown out through a window and seeds settle via chute; overall, the outcome involves method like style, fabrication and collection of various part rising potency and reducing the wastage

Caracterização da qualidade acústica de salas de aula para prática e ensino musical

Resumo O músico necessita perceber adequadamente o som nos recintos destinados ao estudo e prática musical, o que é possível quando estes locais estão acusticamente preparados e permitem o desenvolvimento e aprimoramento da percepção sonora musical. Neste trabalho três salas de estudo e três salas de aula coletiva, destinadas ao ensino e prática de Música de uma universidade, foram caracterizadas acusticamente através da opinião dos músicos usuários e de medições da sua resposta impulsiva. As salas descritas pelos músicos como secas tiveram, nas bandas de frequência de oitava de 500 a 1000 Hz, um Tempo de Reverberação em torno de 0,3 segundos, entre 14 e 22 dB de Clareza e entre 88% a 96% de Definição. As salas caracterizadas como reverberantes tiveram um tempo ao redor de 1,5 segundos, Clareza de 1 dB e Definição de 40%. A opinião dos músicos permitiu compreender as preferências da qualidade acústica das salas e as informações fornecidas pelos músicos se mostraram coerentes com os dados das medições