Impact of noise from urban railway operations

PhD ThesisThis thesis concerns the noise nuisance that results from the operation of urban railways and reports on a case-study of the impact of the Tyneside Metro on residents living in close proximity to the railway tracks. The study was based upon parallel related surveys in the vicinity of Wallsend and Walkergate, during the period August to November 1983: one, a subjective questionnaire survey of perceived noise-nuisance and the other, an objective set of measurements of the actual noise conditions prevailing there. A review of the methods of current practice in the control or urban railway noise demonstrates that regular maintenance of the rails and train wheels is still the most effective way of keeping noise under control at source. Nevertheless, with high speeds of operation, considerable noise nuisance is likely to be experienced by residents nearby. The Metro is the biggest source of noise and noise-nuisance for people exposed to noise levels of over 60 18H Leq dB(A), although the noise annoyance model constructed from the data showed that half of the annoyance felt by respondents could not be explained. Other factors which affect annoyance include vibration, perception of other transport noises, the subjects , ages and whether or not they own the property they occupy. Metro is generally perceived to be quieter and to cause less vibration than the diesel trains (DMUs) which preceded it. The equivalent continuous noise level (Led appears to be the most practical of all the various noise indexes for measuring railway noise annoyance. Finally, informal conversation with respondents in the course of a social survey can provide valuable insight into the mental and psychological processes of perception.The Rees Jeffreys Road Fund: The Ridley Fellowship

Operational behavior of a double-fed permanent magnet generator for wind turbines

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (leaves 117-118).Greater efficiency in wind turbine systems is achieved by allowing the rotor to change its rate of rotation as the wind speed changes. The wind turbine system is decoupled from the utility grid and a variable speed operation is implemented. Since wind speed varies, the shaft speed should too. But electrical output frequency should be synchronous and Induction machines on their own do not allow for variable ratio of shaft speed to electrical frequency. Permanent Magnet (PM) machines have major advantages: Efficiency and power density are both high: they are also inherently synchronous. A prototype ([approx]20 kW) of a novel hybrid machine that encompasses the desired features of Permanent Magnet Generators and Doubly-Fed Induction Generators (DFIGs) is being built. This novel geometry machine has to be tested for stability on a test-bed and controlled using an appropriate power electronics and controller circuit. A MATLAB 5th order model of the machine is built, linearized. simulated and examined for stability. The dynamics of the PM rotor is studied. The electrical equivalent behavior of this component of the machine is vital because the frequency of the output power is a direct function of its mechanical speed. As a culmination of this research work, possible paths for the scope of future work on this technology is presented.(cont.) Keywords: wind turbines, modified torus geometry, permanent magnet, doubly-fed induction. dynamic state-space model, electromechanical stability analysis.by Sivananda Kumjula Reddy.S.M

Preparation and characterisation of 60mol% Al2O3 & 40mol%ZrO2 microcomposite by SOL-GEL precipitation route

A material having two or more distinct constituent materials or phases such that the integrated material has properties noticeably different from constituents is a composite material. For example in alumina-zirconia ceramic composite system, the incorporation of - Al2O3 into stabilized zirconia changes the properties drastically. Ceramic materials traditionally have properties of high compressive strength, high wear resistance, high abrasion resistance and the ability to withstand high temperatures. But one major drawback with ceramic materials is their poor toughness. Zirconia, as a ceramic material, possess remarkable properties such as high melting point, inertness to chemicals, high hardness etc. It has an added advantage that when retained in the tetragonal form in the product during use it gets transformed to monoclinic zirconia and during this process of conversion it increases the toughness of the material- the process known as transformation toughening. This unique property of zirconia can also be used to improve the properties of other ceramic materials like alumina spinel, mullite etc. Transformation toughening is one of the best methods of improving the fracture toughness and strength of brittle ceramic materials. The stability of tetragonal zirconia phase (t-ZrO2) is the main concern in these systems as it determines the stress required for the transformation and thus the resulting toughening achieved. Various combinations of constituent ceramic materials are taken such as Zirconia alumina, Zirconia spinel, Zirconia silicon carbide, Zirconia mullite etc. Objective of our work is to synthesize composite having 60mol% Al2O3 and 40mol% ZrO2 by sol-gel precipitation route. We are adopting this process because the distribution of the ZrO2 particles must be uniform and the size should be slightly lower than the critical diameter at which spontaneous transformation takes place. Before starting this work, a thorough study has been made on the theory, mechanism and the research done by various authors. We have discussed the theory and mechanism of transformation toughening. If the crystal can be restrained from undergoing martensitic transformation during cooling from high temperature by the constraint imposed by the matrix, it can be considered in a metastable state. Should the elastic constraint be removed, as would be the case ahead of the tip in a propagating crack, then the crystal could transform, the shear strain developed would oppose the growth of the crack; it is this effect which is used to advantage in transformation toughening. In our project work we have prepared Alumina powder samples. For this we have adopted sol-gel precipitation route. In this process we have Zirconium oxy chloride and ammonium nitride salt for preparation of powder. From the salts clear solution is prepared. Then gel is formed by addition of ammonia solution which is 50% dilute. This gel is dried in an oven drier. After drying the sample is ground to obtain powder. This dried powder is subjected to calcination at different temperatures starting from 300°C to 1000°C. Then the calcined powders are taken for phase analysis by XRD. We have observed presence of cubic phase in the temperature range of 600°C to 800°C. The disadvantage of cubic phase is that it makes the material prone to fracture. The strength of the sample increases but the toughness is very less. The cubic phase of zirconia is retained in the refractory material where very high strength is required. The tetragonal phase is observed in the temperature range of 800C to 1000°C. This tetragonal phase present in sample, while use transforms into monoclinic phase so the toughness of the material is increased. This process is known as “Transformation Toughening”. The monoclinic phase is generally unstable hence stabilizers a re required. It improves the toughness of the sample

Depressive symptomatology in children with and without learning difficulties.

Thesis (M.Ed.)-University of Natal, Pietermaritzburg, 1997.Though depression in children has received attention in psychological research, the study of depression in special populations has been sadly neglected. Research has indicated that although depression in children is analogous to adult depression it is expressed in different I ways. Comparative studies on children with learning difficulties and children in regular educational programmes report higher levels of depressive symptomatology in the former group. This study investigated depressive symptomatology in Indian children in the age range 8 to 11 at two schools in Durban, South Africa. Levels of depressive symptomatology in 84 children (41 boys and 43 girls) with learning difficulties in a remedial education programme were compared with those of 116 children (57 boys and 59 girls) from the regular education programme. The children with learning difficulties were placed in self-contained classroom units after being psychometrically assessed. The assessment focused mainly on cognitive functioning with little regard for the affective domain. The Children's Depression Inventory (CDI) (Kovacs, 1992) was administered to all the children in the study. Two separate one way anovas were used to analyse the raw score data for: 1) levels of depressive symptomatology in children with and without learning difficulties, and 2) age differences in depressive symptomatology in children with learning difficulties. The chi-square test of significance was used to investigate gender differences in depressive symptomatology in children with learning difficulties. Children with learning difficulties displayed significantly higher levels .- of depressive symptomatology than children in the regular-education programme. The children with learning difficulties obtained a mean score that implies that they are mildly depressed. There were no statistically significant age and gender differences. However, an age trend was noted in that younger children displayed higher levels of depressive symptomatology than older children. These findings are similar.to those of other authors (Hall and Haws, 1989; Wright-Strawderman and Watson, 1992). Implications of these results are discussed in terms of the relationship between depression and learning difficulties; the assessment of children with learning difficulties; the role of school psychologists and teachers; and the treatment of depressive symptomatology in children with learning difficulties

Pengaruh Penambahan Serat Ijuk Terhadap Stabilitas Campuran Aspal Emulsi Dingin

Serat ijuk merupakan serat alami yang mudah ditemukan, tetapi belum dimanfaatkan secara optimal. Penelitian ini dilakukan untuk mengetahui pengaruh penambahan serat ijuk terhadap stabilitas Campuran Aspal Emulsi Dingin (CAED). CAED adalah campuran antara agregat bergradasi menerus dan aspal emulsi sebagai bahan pengikat. Aspal emulsi adalah aspal berbentuk cair yang dihasilkan dengan mendispersikan aspal keras ke dalam air atau sebaliknya dengan bantuan bahan pengemulsi sehingga diperoleh partikel aspal yang bermuatan listrik positif atau negatif atau tidak bermuatan listrik. Pengujian Marshall dilakukan pada CAED tanpa dan dengan tambahan serat ijuk dengan waktu curing selama 0 dan 7 hari untuk mendapatkan nilai stabilitas. Hasil penelitian menunjukkan semakin banyak kadar serat ijuk yang ditambahkan maka stabilitas meningkat. Stabilitas CAED dengan serat ijuk umur curing 0 hari meningkat pada kadar ijuk 0,1% - 0,3% lalu mengalami penurunan pada kadar ijuk 0,4%. Stabilitas kadar ijuk 0,3% lebih tinggi daripada CAED tanpa serat ijuk. Stabilitas CAED dengan serat ijuk umur curing 7 hari meningkat pada kadar ijuk 0,1% - 0,4% dan masih bisa terus naik. Stabilitas kadar ijuk 0,4% lebih tinggi daripada CAED tanpa serat ijuk. Panjang serat ijuk antara 0,1 – 0,25 cm. Waktu curing selama 7 hari meningkatkan stabilitas CAED tanpa dan dengan tambahan serat iju

OPTIMASI SUHU DAN KONSENTRASI ASAM ASETAT PADA REAKSI EPOKSIDASI METIL ESTER MINYAK SAWIT

Minyak nabati kaya akan kandungan asam lemak tak jenuh dari jenis asam oleat, linoleat, dan linolenat yang dapat dikonversi menjadi gugus senyawa epoksida. Minyak epoksida memiliki banyak kegunaan diantaranya sebagai plastisiser untuk memperbaiki fleksibilitas, el;astisitas, dan stabilitas bahan karena pengaruh panas dan radiasi. pada penelitian ini, minyak sawit dikonversi terlebih dahulu menjadi metil ester minyak sawit (MEMS) dan kemudian dilanjutkan reaksi epoksidasi menghasilkan metil ester minyak sawit terepoksidasi (MEMST). Metode response surface digunakan untuk optimasi dan mempelajari pengaruh suhu reaksi dan rasio mol MEMS/CH3COOH terhadap konversi reaksi dan bilangan oxirane. Kondisi reaksi yang optimal ditunjukkan oleh kandungan gugus oxirane yang tinggi yaitu bilangan oxirane. Reaksi epoksidasi dilakukan di dalam reaktor batch menggunakan asam asetat sebagai senyawa pembawa oksigen. Central Composite Design (CCD) dengan dua variabel independent dan dua fungsi response digunakan untuk mempelajari pengaruh variabel input. Hasil penelitian menunjukkan konversi reaksi meningkat dengan meningkatnya suhu reaksi dan rasio mol MEMS/CH3COOH sebelum mencapai titik maksimum dan kemudian turun secara monoton. Kondisi reaksi epoksidasi yang optimal ditunjukkan oleh bilangan oxirane maksimum yang dicapai pada suhu reaksi 56,3oC dan rasio mol MEMS/CH3COOH adalah 1:0,4

TEMPERATURE AND ACETIC ACID CONCENTRATION OPTIMATION IN THE EPOXIDATION REACTION OF PALM OIL METHYL ESTER

Vegetable oils are rich in content unsaturated fatty acid from the type of oleic acid, linoleic acid andlinolenic acid that can be converted to epoxide groups. Epoxidized oil has many useful applications such asplastisizer to improve flexibility, elasticity and stability under the influence of heat and radiation. In thisresearch, palm oil was converted first to become palm oil methyl ester (POME), followed by epoxidationreaction to produce epoxidized palm oil methyl ester (EPOME). Response surface method (RSM) was performedfor optimization and to study the influence of reaction temperature and molar ratioPOME/CH3COOH on the conversion reaction and oxirane value. An optimal reactional condition was shownby high oxirane content which was in the form of oxirane counts/number. Epoxidation reaction was run inthe batch reactor using acetic acid as an oxygen carrier. Central Composite Design (CCD) with two independentvariables and two response function was utilized to investigate the effect of input variables. Theresult shows that reaction conversion increased with the rise of reaction temperature and molar ratio ofPOME/CH3COOH before reaching the maximum point, and then it monotonously decreased. The optimaloperating condition for epoxidation reaction was indicated by maximum oxirane value which could bereached by the reaction temperature of 56.3 oC and molar ratio POME/CH3COOH of 1:0.43Key words: epoxidation, methyl ester, oxirane, palm oi

The preparatory Set: A Novel Approach to Understanding Stress, Trauma, and the Bodymind Therapies

Basic to all motile life is a differential approach/avoid response to perceived features of environment. The stages of response are initial reflexive noticing and orienting to the stimulus, preparation, and execution of response. Preparation involves a coordination of many aspects of the organism: muscle tone, posture, breathing, autonomic functions, motivational/emotional state, attentional orientation, and expectations. The organism organizes itself in relation to the challenge. We propose to call this the preparatory set (PS). We suggest that the concept of the PS can offer a more nuanced and flexible perspective on the stress response than do current theories. We also hypothesize that the mechanisms of body-mind therapeutic and educational systems (BTES) can be understood through the PS framework. We suggest that the BTES, including meditative movement, meditation, somatic education, and the body-oriented psychotherapies, are approaches that use interventions on the PS to remedy stress and trauma. We discuss how the PS can be adaptive or maladaptive, how BTES interventions may restore adaptive PS, and how these concepts offer a broader and more flexible view of the phenomena of stress and trauma. We offer supportive evidence for our hypotheses, and suggest directions for future research. We believe that the PS framework will point to ways of improving the management of stress and trauma, and that it will suggest directions of research into the mechanisms of action of BTES