## 3 Results
### Linking Experimental Design and Results
For the annotation of natural language text, tribAIn provides three annotation properties _textualHypothesis, textualInterpretation_, and _textualDescription_. The hypothesis in this example was formulated as an aim attached to the whole test series. In contrast, the experimental results are separately discussed for friction and wear behavior and the target variables respectively in the publication. Since an assertion about the influence of friction and wear behavior is a comparison between the sample and reference groups with varied tribosystems in this case, the annotated section in the publication was attached to the corresponding groups and the target variable. For instance, the results for a relative humidity of 20% showed an up to 2.3-fold reduction of friction for the MXene-coated bodies compared with the uncoated references (Figure 10, _tAI:textualInterpretation_), whereby the target variable formally signs which parameter was investigated for this result. Yet, not only the influence of coated samples compared with uncoated reference samples was investigated in this test series. Thus, some annotations of the experimental results were attached to two different sample or reference groups, which were compared, for instance, with regard to the influence of pressure variation. Moreover, ontological annotations using tribAIn makes explicit that the results for the research aim of the whole series are classified into more than one category concerning different aspects of the applicability of MXene nanosheets as solid lubricant. For instance, the results for friction and wear behavior are separately annotated, while this is not explicitly stated in the textual research aim. Besides the interpretation of experimental results for a specific tribosystem, a consistent and transparent documentation of tribological knowledge, requires also access to the measured raw data from which the processed results are derived. Considering the output files from the present use case, the CSV format is quite inappropriate to retrace result interpretation or comparing data. Since the headers of the CSV files contain provenance information as well as data about the investigated tribosystem,  
Figure 10: Linking annotations from a publication to tribAIn concepts. the files have to be processed for categorization and comparison of the indicating parameters for the friction and wear behavior of the investigated tribosystems. As different parameters are measured within the same test setup, an individual series is generated as a triple store from the CSV files for each parameter. For instance, the _COF_ was measured over a time period for a specific sample, thus every single value was modeled as an individual (_COF_ID_), containing information about the _TimeStamp_ and the value (Figure 11). Thereby, the _COF_ is a dimensionless quantity with no information about the unit being attached in this case. Every individual _COF_ (_COF_[_ID_]) is a parameter of the individual measurement series (_SeriesCOF_[_ID_]) for each sample. Using the concepts from tribAIn to transform the CSV data into a triple store provides an explicit link between the investigated tribosystem defined for a sample group. Moreover, handling the measurement series of different parameters as single objects enables comparison of the trend of a specific parameter within different samples separately. Since the component tests were more complex but produced output files similar to the model tests, the results can be linked equally. In this investigation, commercially available thrust ball bearings 51,201 (ISO 104) consisting of a ball cage assembly (_Body_), a shaft washer (_CounterBody_), and a housing washer (_CounterBody_) build the studied tribosystem (Figure 12). Since all substrates of the _SampleGroup_ were coated with Ti\({}_{3}\)C\({}_{2}\)T\({}_{x}\) nanosheets, the MXenes are defined as _InterfacialMedium_. For the thrust ball bearings, a datasheet is available containing dimensional information and is linked using an individual of the concept _TechnicalDescription_.