<p>U radu je razmatran problem projektovanja polužnih mehanizama koji se primenjuju u sistemima elastičnog oslanjanja drumskih vozila.<br />Polužni mehanizmi za vođenje točka imaju zadatak da ostvare pokretnu vezu točka sa nosećim strukturama vozila koja omogućava približno vertikalno relativno kretanje točka u odnosu na telo vozila i obezbeđuje prijem aktivnih i reaktivnih sila i momenata nastalih u interakciji točka sa podlogom.<br />Definisana je jednostavna, univerzalna metoda za optimalnu sintezu mehanizama u sistemima oslanjanja vozila, koja ne zahteva pripreme i prilagođavanje različitim specifičnim uslovima i zahtevima sinteze mehanizama u okvirima ove tematike. Osnovne karakteristike predloženog postupka su: tačnost i praktična primenljivost usvojenog metodološkog prilaza; jednostavnost i univerzalnost celokupnog postupka sinteze, osigurana usvajanjem algoritma diferencijalne evolucije kao optimizacione metode; robusnost metoda i odsustvo potrebe za pripremom i prilagođavanjem različitim postavkama problema sinteze; implementacijom postupka u okruženju opšteg matematičkog programa Mathcad omogućeno je da svi elementi proračuna (ulazni podaci, jednačine, komentari, skice, dijagramski prikazi i numerički rezultati) budu objedinjeni na jednom mestu.Primena razvijenog postupka sinteze demonstrirana je na karakterističnim problemima optimalne sinteze mehanizama za oslanjanje vozila. Problemi su postavljeni tako da je zadato kretanje nosača točka - generisano je mehanizmom poznate konfiguracije. U takvoj postavci problema, u kojoj se pouzdano zna da se zadato kretanje nosača točka može ostvariti, izvedeni su numerički eksperimenti sa višestrukim ponavljanjem postupka sinteze uz variranje početnih vrednosti nepoznatih konstrukcionih parametara slučajnim izborom iz širokih intervala. Dobijeni rezultati su pokazali da je u svim slučajevima razvijeni postupak sinteze rezultovao mehanizmom koji ostvaruje zadato kretanje uz odstupanja znatno ispod praga fizičke značajnosti.</p> / <p>This paper is focused on the design of lever mechanisms used in systems for elastic vehicle suspension.<br />The lever mechanisms used for wheel guidance are tasked with accomplishing a mobile connection between the wheel and the support structure that allows the wheel a roughly vertical motion relative to the vehicle body and receives the active and reactive forces and torque originating from the interaction between the wheel and the ground.<br />A simple, universal method for the optimal synthesis of mechanisms used in vehicle support systems is defined, one that doesn&rsquo;t require extensive preparation or adjustments for specific conditions. The basic characteristics of the proposed method are: accuracy and practical applicability of the method; simplicity and universality of the whole synthesis process, insured by adopting the differential evolution algorythm for the optimization method; robustness of the method and the lack of need for preparation and adjustments to the different synthesis peoblems; by implementing the method in the universal mathematical program Mathcad, the calculation elements (input, equations, comments, sketches, diagrams and numerical resuts) are all presented and accessible in one place.<br />The application of the developed method is demonstrated on charachetirstic problems of the optimal synthesis of vehicle support mechanisms. The problems are set up so that the motion of the wheel support is known &ndash; it is generated by a mechanism with a known configuration. In this kind of setting, where one is sure the given motion of the wheel support can be accomplished, a series of numerical tests was performed with multiple repetitions of the synthesis method using different initial values of the unknown construction parameters randomly chosen from wide intervals. The results of these experiments have shown that for each set of initial values, the developed method resulted in a mechanism that accomplished the required motion with very slight deviations, too small to be of any practical importance.</p>

The negative effects of retributive disciplinary measures in school settings are well documented. Exclusionary practices, such as suspensions, position students on the school-to-prison pipeline, perpetuating a cycle of failure. Restorative justice practices in educational settings provide an alternative to the retributive approach to student discipline. In this research study, a middle school in California was examined for its implementation of restorative justice practices. Numerical data pertaining to a five-year suspension history report for the school were utilized for the quantitative analyses, and four individual chi-square goodness of fit tests were conducted. The results demonstrated that the implementation of restorative justice played a significant role in the declining student suspensions across school years. It was found that the introduction of restorative practices to the middle school played a role in creating an inclusive school environment, with student suspensions having been applied to a lower proportion of African American and Hispanic students from pre-implementation of restorative justice to post-implementation. Through the use of a restorative framework, students may learn how to solve problems and repair relationships in school and life events, rather than being placed on the school-to-prison pipeline.

Thesis (LLM. (Labour Law)) -- University of Limpopo, 2013 / The study will analyse the fairness or unfairness of precautionary suspensions and the rights of employees in the Public Service who are placed on precautionary suspensions with reference to section 23(1) of the Constitution of the Republic of South Africa, 1996, which states that: (1) “ Everyone has the right to fair labour practices” Section 186(2)(b) of the Labour Relations Act 66 of 1995 defines what an unfair labour practice is with specific reference to a precautionary suspension. It reads thus: (2) “ Unfair labour practice means any unfair act or omission that arises between an employer and an employee involving – (b) the unfair suspension of an employee or any other unfair disciplinary action short of dismissal in respect of an employee” The study will also look at circumstances under which precautionary suspension is invoked on Senior Management Service employees in the public service in terms of chapter 7, clause .2.7(2) of the Senior Management Service Handbook, 2003. Decided cases will be referred to which shows that one of the reasons why many precautionary suspensions are set aside when challenged in court, is because some employees who are assigned to deal with labour issues in the government departments are not competent to deal with those issues. The issue of political appointments impacts directly on service delivery if people are appointed to positions because of political affiliation than competency.

L'amidon utilisé comme épaississant alimentaire présente tout d'abord un intérêt nutritif mais offre également une meilleure perception du goût comparé à d'autres épaississants de type hydrocolloide. Cette propriété semble liée à la capacité des produits à se mélanger en bouche et donc à la diffusion des agents de flaveurs aux récepteurs. Un paramètre physique qui pourrait refléter la capacité à se mélanger serait la facilité d'une goutte de cet épaississant à rompre lorsque celle-ci est soumise à un cisaillement. Le but de cette étude est de comprendre le comportement d'une goutte de suspension de granules d'amidon, gonflés dans l'eau, sous écoulement et de le comparer à une goutte d'un autre épaississant connu, la solution aqueuse de hydoxyproplmethyl cellulose (HPMC). Les gouttes, placées dans l'huile de silicone, sont étudiées sous cisaillement à l'aide d'un rhéo-optique contra-rotatif. Les conditions de rupture d'une goutte de suspension d'amidon sont étudiées en détails et comparées à celle d'une goutte d'HPMC. Le mécanisme de rupture d'une goutte de suspension est différent comparé à une goutte de solution d'HPMC. La déformation d'une goutte de suspension a été liée au comportement rhéologique de la suspension et à la déformation d'un granule seule gonflé sous cisaillement.

<p>Eutrophication is a current problem on coastal lines worldwide. Cirripedia like the northern acorn barnacle Semibalanus balanoides actively help to prevent high amounts of plankton in the coastal zones by filtering plankton out of the surrounding water. This investigation focuses on the movements of Semibalanus balanoides in comparison to increasing concentrations of plankton in the water (between 33mg and 110 mg particles per litre) which simulate eutrophication. The four factors feeding activity, pumping activity, isolation time and clogging of the feeding apparatus in relation to the plankton concentration of the water were examined. </p><p>The results show significant interaction between pumping movement and the plankton concentration. The feeding activity, the isolation time and the clogging compared to the plankton concentration get no statistical results. </p><p>Less feeding activity and an increase in pumping behaviour will not decrease the amount of plankton in the coastal waters which will increase the problems of eutrophication. The paper shows that more investigation on suspension feeders and their surroundings needs to be done to be able to understand the dangers fully.</p>

<p>A colloid of magnesium hydroxide is used to stabilize droplets of monomers before suspension polymerisation. The characteristics of precipitated magnesium hydroxide changes significantly during the first hours. The viscosity is high and flucctuating at first but decreases and becomes low and stable after a few hours. When the colloid ages the primary particles agglomerate into larger particles which increases in size by time due to, among other things, Oswald ripening and aggregation. This can cause problems with poor reproducibility in the production. Therefore, the purpose of this study was finding a way to age the colloid without an increase in particle size and without changing any other features. Several experiments were made to optimize the precipitation procedure and to find out what parameters that are most important. The results showed that the stirring rate and colloidal concentration have big influence.</p><p>Small amounts of chemicals that modifies the surface of the colloid was added. This made the particle size near constant over time and the colloid was aged for two months without increasing in size or changing other properties. This was confirmed by making microspheres that had the same characteristics as microspheres made with a fresh colloid.</p>

No description available.

Eutrophication is a current problem on coastal lines worldwide. Cirripedia like the northern acorn barnacle Semibalanus balanoides actively help to prevent high amounts of plankton in the coastal zones by filtering plankton out of the surrounding water. This investigation focuses on the movements of Semibalanus balanoides in comparison to increasing concentrations of plankton in the water (between 33mg and 110 mg particles per litre) which simulate eutrophication. The four factors feeding activity, pumping activity, isolation time and clogging of the feeding apparatus in relation to the plankton concentration of the water were examined. The results show significant interaction between pumping movement and the plankton concentration. The feeding activity, the isolation time and the clogging compared to the plankton concentration get no statistical results. Less feeding activity and an increase in pumping behaviour will not decrease the amount of plankton in the coastal waters which will increase the problems of eutrophication. The paper shows that more investigation on suspension feeders and their surroundings needs to be done to be able to understand the dangers fully.

A colloid of magnesium hydroxide is used to stabilize droplets of monomers before suspension polymerisation. The characteristics of precipitated magnesium hydroxide changes significantly during the first hours. The viscosity is high and flucctuating at first but decreases and becomes low and stable after a few hours. When the colloid ages the primary particles agglomerate into larger particles which increases in size by time due to, among other things, Oswald ripening and aggregation. This can cause problems with poor reproducibility in the production. Therefore, the purpose of this study was finding a way to age the colloid without an increase in particle size and without changing any other features. Several experiments were made to optimize the precipitation procedure and to find out what parameters that are most important. The results showed that the stirring rate and colloidal concentration have big influence. Small amounts of chemicals that modifies the surface of the colloid was added. This made the particle size near constant over time and the colloid was aged for two months without increasing in size or changing other properties. This was confirmed by making microspheres that had the same characteristics as microspheres made with a fresh colloid.

Blood is a dense suspension of flexible red blood cells. In response to a background flow, these cells distribute themselves non-uniformly throughout the vessel. As a result, material properties that are well defined in homogeneous fluids, such as viscosity, are no longer so, and depend upon the flow geometry along with the particle properties. Using a simple model that accounts for the steady-state particle distribution in vessel flow, we derive an expression for the effective viscosity of blood and the suspension flow velocity field in a pressure-driven tube flow. <br /><br /> We derive the steady-state particle distribution from a conservation equation with convective flux arising from particle deformation in the flow. We then relate the particle microstructure to the overall flow through a generalized Newtonian stress-tensor, with the particle volume fraction appearing in the expression for the local viscosity. Comparing with experimental data, we show that the model quantitatively reproduces the observed rheology of blood in tube flow. <br /><br /> We reconsider the problem in an alternate geometry corresponding to the flow between two concentric cylinders. The steady-state particle distribution, suspension velocity field and the measured effective viscosity are all very different from their counterparts in tube flow, casting serious doubt upon the practice of using data from a Couette viscometer to parameterize constitutive models applied to vascular blood flow. <br /><br /> Finally, we calculate the effect of random fluctuations in the particle velocity on the averaged behaviour of the particle conservation equation. Using a smoothing method for linear stochastic differential equations, we derive a correction to the free Einstein-Stokes diffusion coeffcient that is due to the interaction of the particles with their neighbours.