The thesis on the topic of the influence of the time period distance of the harvest from the end of the vegetation on the occurrence of "potato fenkines on the bulbs." There were 11 varieties of the potatoes chosen for the observation. Their vegetation was terminated by the desication resource called Reglone. From the end of the terminated vegetation during 10 days until the harvest there were 4 samples taken and they were evaluated on the occurrence and it's percentage of the "potato flakiness on the bulbs" in accordance with the scale of Wenzel and Demel (1976). There were there varietes selected for the evaluation; Flavia (VR), Riviera (VR), Rosara (VR), Merida (R), Adéla (R), the Baccara (R), Marabel (R), Ditta (PR), Laura (PR), Maréna (PP) and Saturn (PP). The achieved results of the "potato flakiness" weere evalunted statistically. The aim of the evlution of the ("potato flakiness on their bulls") Rhizoctonia solani. The term of the vegetation termination depends on the grover and must be in written documentation. The harvest alome can follow after the the drawal period in the desiccation resource, which uswally 15 days. The results indicale that whem the harvest of the potatoes is made at the proper time after the termination of the vegetation, the potato bulls are withhout any largen percentage accurence of the "flakiness". The results achieved during the years 2012 and 2013 indicate that in early implementation off all the working operations important for the potato growing, which begin with sorting out, followed by plantig, care, chemical sprays, selection, parades, desiccation and the harvest, the "flakiness" dinďt exceed 5% of the occurence. Another results indicate that the taken bulls were undamaged and the difference of the occurrence of the "flakiness"on each sample appeared in a variety of ways. The years of abseving the experiment proved that there was an increase in the "flakiness" on the surface for a given time period.

Regression testing is an essential part of developing and maintaining software. It helps verify that changes to the software have not introduced any new bugs, and that the functionality still works as intended. However, for this verification to be valid, the executed tests must be assumed to be deterministic, i.e. produce the same output under the same circumstances. Unfortunately, this is not always the case. A test that exhibits non-deterministic behavior is said to be flaky. Flaky tests can severely inhibit the benefits of regression testing, as developers must figure out whether a failing test is due to a bug in the system under test (SUT) or test flakiness. Moreover, the non-deterministic nature of flaky tests poses several problems. Not only are the failures difficult to reproduce and debug, but developers are more likely to ignore the outcome of flaky tests, potentially leading to overlooked bugs in the SUT. The aim of this thesis was to investigate the applicability of execution tracing techniques as a means of providing root cause analysis for flaky tests in the randomness and network categories. This involved reproducing and studying flakiness, as well as implementing and evaluating a prototype with the ability to analyze runtime behavior in flaky tests. To gain a better understanding of reproducibility and common traits among flaky tests in the selected categories, a pre-study was conducted. Based on the outcome of the pre-study and findings in related literature, the network category was dropped entirely, and two techniques were chosen to be implemented. The implementation process resulted in the FlakyPy tool, a plugin for pytest that provides root cause analysis aimed at randomness flakiness. When run against a dataset of 22 flaky tests, the tool was able to identify potential root causes in 15 of these. This serves as an indication that execution tracing has the potential of detecting possible root causes in flaky randomness tests in Python. However, more research is needed to evaluate how developers perceive the usefulness of such tools.

With today’s focus on Continuous Integration, test cases are used to ensure the software’s reliability when integrating and developing code. Test cases that behave in an undeterministic manner are known as flaky tests, which threatens the software’s reliability. Because of flaky test’s undeterministic nature, they can be troublesome to detect and correct. This is causing companies to spend great amount of resources on flaky tests since they can reduce the quality of their products and services. The aim of this thesis was to develop a usable tool that can automatically detect flakiness in the Randomness category. This was done by initially locating and rerunning flaky tests found in public Git repositories. By scanning the resulting pytest logs from the tests that manifested flaky behaviour, noting indicators of how flakiness manifests in the Randomness category. From these findings we determined tracing to be a viable option of detecting Randomness as a cause of flakiness. The findings were implemented into our proposed tool FlakyReporter, which reruns flaky tests to determine if they pertain to the Randomness category. Our FlakyReporter tool was found to accurately categorise flaky tests into the Randomness category when tested against 25 different flaky tests. This indicates the viability of utilizing tracing as a method of categorizing flakiness.

Concrete is one of the world’s most common construction materials and is composed of 70-80 % stone material. Today crushed stone is used as aggregate in concrete in order to replace natural aggregates due to strong environmental reasons. Stone crushing yields flaky material and in this thesis studies are made on the flaky particle shape and how it influence properties of concrete such as workability, rheology and strength. The concrete recipes used in this thesis have fixed values, the only variable is the flakiness of the crushed stone. Flakiness is varied between 0 %, 17 %, 50 %, and 100 % in turn for the individual size fractions 2-8 mm, 8-10 mm, 10–12.5 mm, and 12.5–16 mm. By using Swedish and European standards one determines flakiness index, packing factor, slump test, Thaulow tester, compression strength and flexural strength. The Bingham model is applied with the use of a viscometer to determine the concretes rheological properties such as plastic viscosity and yield stress. For the individual size fraction 12.5-16 mm a flow analysis is performed in an L-box to study how the particles are orientated with the flow direction, and how this influences the strength and crack length. Results show that the loose packing factor decreases with increased flakiness for all individual size fractions. Fractions 2-8 mm and 8-10 mm need a small increase in super plasticizer with increased flakiness to achieve 200 mm slump. The larger individual size fractions do not show any increase in super plasticizer regarding this matter. The Thaulow tester indicates constant values with increased flakiness for all individual size fractions except 2-8 mm were a weak increase is observed. Values of the plastic viscosity are indicated unchanged as the flakiness index is increased for all individual size fractions except 2-8 mm that slightly increase for 100 % flakiness. The yield stress behaves unchanged with increased flakiness for all individual size fractions except 12.5-16 mm which significantly decrease for 100 % flakiness. When the concrete flows in the L-box an image analysis concludes that the larger amounts of flaky particles are orientated with the flow direction. The crack length increases with higher flakiness for fraction 12.5-16 mm but this does not lead to an increase in strength. Flexural strength increase with higher flakiness, this is clearly observed for the two largest individual size fractions. Compressive strength is indicated to be independent of flakiness and is approximately constant for all individual size fractions except individual size fraction 12.5-16 mm that indicates an increase. High flakiness on cone crushed granite rock in size fraction 8-16 mm from the bedrock in Enhörna is not regarded as disadvantageous for concrete manufacturing, as it shows good values in workability, rheology and strength. / Betong är ett av världens vanligaste byggmaterial och består av ungefär 70-80 % stenmaterial. Idag används krossten som ballast i betong för att ersätta naturgrus av starka miljöskäl. Stenkrossning ger upphov till flisigt material och i detta arbete studeras den flisiga kornformen och hur den påverkar betongens egenskaper inom arbetbarhet, reologi och hållfasthet. Blandningsreceptet har fixerade värden och den enda variabeln som varierar i arbetet är flisigheten på krosstenen. Flisigheten varieras mellan 0 %, 17 %, 50 % och 100 % i tur och ordning för delfraktionerna 2-8 mm, 8-10 mm, 10–12.5 mm, och 12.5–16 mm. Genom att använda svenska och europeiska standarder bestäms flisighetsindex, packningsindex, sättmått, omformningstal, tryckhållfasthet och böjdraghållfasthet. Bingham modellen tillämpas för att med hjälp av en viskometer bestämma betongens reologiska egenskaper som plastisk viskositet och flytgränsspänning. För delfraktionen 12.5-16 mm utförs även flödesanalys med hjälp av en L-låda för att studera hur partiklar orienterar sig med flödesriktningen, och hur detta påverkar hållfastheten och spricklängden. Resultat visar att den lösa packningsgraden sjunker med ökad flisighet för samtliga delfraktioner. Fraktionerna 2-8 mm och 8-10 mm kräver en liten ökning av plasticerarmängden med ökad flisighet för att uppnå sättmått 200 mm. De större delfraktionerna visar dock ingen ökning av plasticerarmängd i detta avseende. Omformningstalet är i princip konstant med ökad flisighet för samtliga fraktioner förutom för 2-8 mm fraktionen där en svag ökning kan dokumenteras. Den plastiska viskositeten indikeras oförändrad då flisighetsindex ökar för samtliga delfraktioner förutom 8-10 mm fraktionen som ökar en aning vid 100 % flisighet. Flytgränsspänningen beter sig konstant med ökad flisighet för samtliga delfraktioner förutom 12.5-16 mm som signifikant sjunker för 100 % flisighet. När betongen flyter i L-lådan dras slutsatsen från bildanalys att den största delen flisiga partiklar orienterar sig med flödesriktningen. Spricklängden ökar med större flisighet för fraktionen 12.5-16 mm men detta visar ingen ökning i hållfastheten. Böjdraghållfastheten blir högre med ökad flisighet, denna trend visas tydligast av de två största delfraktionerna Tryckhållfastheten kan indikeras vara oberoende av flisighet och är ungefär konstant för samtliga delfraktioner förutom delfraktion 12.5-16 mm som indikerar en ökning. Hög flisighet på konkrossad granitsten fraktion 8-16 mm från bergtäkten i Enhörna anses inte vara ogynnsam för betongtillverkningen, då den ger goda värden på arbetbarhet, reologi och hållfasthet.

The characteristics of fine aggregates, such as shape, angularity, and surface texture, have been shown to influence the performance of concrete and asphalt mixtures and to play an important role in obtaining valuable properties of early age concrete such as workability, and compatibility. However, the measurement of fine aggregate characteristics is not easy. In the present study, 26 fine aggregates, covering a wide spectrum of mineralogy, were examined using direct and indirect test methods in order to evaluate the shape, angularity, and surface texture, as well as to analyze the gradation. The direct test methods, such as AIMS and Camsizer, which provide a digital image of the aggregates proved to be the best. However, the cost of such systems can limit the use of digital imagining systems in practice. The indirect test methods which provide an estimate of aggregate surface characteristics, such as uncompacted void test, mortar flow test, compressive strength test, and flakiness test gave variable results. The uncompacted void test (Method A) was shown to be the most accurate indirect test method. The Camsizer and the sieve analysis test produced identical gradation analysis results when an adequate sample was used. General correlations were developed between the direct and indirect test methods. The non-approved fine aggregates on the TxDOT’s list were analyzed and compared to those of the approved fine aggregates to see whether they could be successfully used. It was found that both LS-5 and LS-8 had good results—even better than the results of some of the approved fine aggregates. Thus, they could be successfully used. / text

African copper PLC’s flagship is the copper producing Mowana mine located 129 km from Francistown in the North-Eastern part of the Republic of Botswana. The processing operation at Mowana is a standard flotation plant designed to produce copper concentrates from oxide, supergene, and sulphide ores. The expected average output of 16.2 tons per hour of copper concentrates has never been attained since plant commissioning. The major bottleneck has been established to be located around the crushing circuit of the Mowana production chain. The major hypotheses of this research are that performance in a crushing plant is adversely influenced by moderate and discrete changes in the process. The ultimate objective is to develop a dynamic process simulator, administered in Simulink/MATLAB® background, for application in the design of a control model utilising two crusher variables and a self-tuning control algorithm. In this research work, a process model describing the dynamic operation of an Osborn 57S gyrasphere cone crusher is investigated. Modelling of the Mowana crushing circuit is carried out by combining the steady-state and dynamic components of the crushing equipment in the Simulink/Matlab® environment. Eccentric speed (ES) and closed-side setting (CSS) are amongst the important inputs to the models. The rest of the inputs (crusher power, crusher cavity level, federate, pulley diameters, liner wear measurement, number of teeth of the pinion and bevel gear) are extracted from the data collected across the Mowana mine crushing circuit. While it has been demonstrated that the crusher CSS is the most influential controllable parameter, it has also been demonstrated that crusher capacity and power can be used effectively to optimise the circuit. The use of crushing power and cavity level control is suitable for the crushing circuit since the crushers are running on a constant ES and the CSS is set and reset manually. The outcome of the study presents an insight into the optimization of the Mowana mine crushing circuit through the design of a self-tuning controller for the cone crusher and for prototyping, parameters of a PID controller were determined in the Simulink/MATLAB® environment. The simulation involved the optimisation of the control model as a function of the cavity level of and the power drawn by the cone crusher. A self-tuning control algorithm at PLC and SCADA level of control was then tested. This formed the simulations and training platform. The outcome of the simulations carried out in this research needs to be validated against the real Mowana crushing process control upgrade. This will then inform the modifications and recommended crusher motor resizing exercise to be implemented. / Electrical and Mining Engineering / M. Tech. (Engineering: Electrical)