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The purpose of this paper is to present new basis functions suitable to parameterize two‐dimensional static potentials or (magnetic) fields and to show their application in practical cases.

Regular multipole solutions of the potential equation in plane elliptic coordinates are found by separation. The resulting set of functions is reduced to complete subsets suitable for expanding regular potentials or irrotational source‐free fields. Approximate regular plane solutions of the potential equation in local toroidal coordinates are computed by R‐separation and power series expansions in the inverse aspect ratio. The harmonic signals induced in a coil rotating in such a toroidal multipole field are computed from the induction law by similar expansions.

The elliptic expansions are useful in a larger area than circular multipole expansions and give better fits. The toroidal expansions permit one to estimate the effect of the curvature of magnets on the field and give better adapted expansions. However, while the scalar multipoles for the potential are orthogonal the vector fields derived for the two‐dimensional field are not.

Derivations presuppose analytical fields.

Field data obtained from numeric field calculations or measurements do not represent exactly analytic fields. Application of the expansion requires care and checks.

The paper presents novel approaches for parameterizing longitudinally uniform cylindrical or toroidally uniform potentials and fields.

The purpose of this paper is to identify the crack in beam-like structures before the complete failure or damage occurs to the structure. The beam-like structure plays an important role in modern architecture; hence, the safety of this structure is much dependent on the safety of the beam. Hence, predicting the cracks is much more important for the safety of the overall structure.

In the present work, the regression analysis has been carried out through LASSO and Ridge regression models. Both the statistical models have been well implemented in the detection of crack depth and crack location. A cantilever beam-like structure has been taken for the analysis in which the first three natural frequencies have been considered as the independent variable and crack location and depth is used as the dependent variable. The first three natural frequencies, f₁, f₂ and f₃ are used as an independent variable. The crack location and crack depth are estimated though the regressor models and the accuracy are compared, to verify the correctness of the estimation.

As stated in the purpose of work, the main aim of the present work is to identify the crack parameters using an inverse technique, which will be more effective and will provide the results with less time. The data used for regression analysis are obtained from theoretical analysis and later the theoretical results are also verified through experimental analysis. The regression model developed is tested for its Bias Variance Trade-off (“Bias” – Overfitting, “variance” – generalization). The regression results have been compared with the theoretical results to check the robustness in the subsequent result section.

The idea is an amalgamation of existing and well-established technologies, that is aimed to achieve better performance for the given task. A regressor is trained from the data obtained through numerical simulation. The model is developed taking bias variance trade-off into consideration. This generalized model gives us very much acceptable performance.

This study aims to analyse the variations of thermal comfort inside a building space by using different curtains.

Phase change materials (PCMs) such as wax, sand and mixture of sand and wax were used with cotton curtain to compare the results of PCM curtains with the performance of normal cotton curtain against constant heat exposure. Heat exposure was provided with halogen to simulate the solar radiation. Further simulation was performed on ANSYS and experimental results were compared with the simulation results. In addition to this, the results were analysed for optimized performance by calculation root mean square error.

It was found that PCM used curtains that have better performance than normal curtain. Furthermore, sand curtain was proved as the best curtain and mixture of sand and wax curtain could replace the sand curtain where there is limitation of weight; also, there was less error between experimental and simulation was reported for sand curtain as compare to other curtains.

Layers of different PCMs were used before cotton curtain and in modelling assumptions such as one-dimensional heat transfer, uniform thermal conductivity.

To the best of the authors’ knowledge, there is no such study that was performed earlier.

In reinforced concrete (RC) structures, an evidence of damage is the presence of cracking. In order to evaluate the effect of damage on cracking pattern and natural frequency in RC slabs, two of such structures with different dimensions and reinforcement ratios were tested, in which cracks were induced through application of static load, followed by modal tests using impact excitation. The paper aims to discuss this issue.

The gradient of the fundamental natural frequency along the decay, the crack opening rate and also a global damage index based on changes of the fundamental natural frequency were evaluated.

The behaviour of the aforementioned gradient was distinct for both slabs, increasing monotonically with the cracking level for the slab with lowest reinforcement ratio, and increasing until 33 per cent of the collapse load and then decreasing afterwards for the slab with the highest ratio. Changes of the gradient were consistent with changes of the crack opening rate. Both results of gradient changes and cracking pattern brought evidence that the balance between open (old) and breathing (new) cracks differed between the slabs, and may be responsible for such differences.

Damage assessment in RC structures using vibration tests is mostly concentrated on beams. In this work, an advance is made by investigating slabs. The lack of a unique pattern of changes of the gradient implies that its absolute value is not generally suitable for the association with the damage level. However, the impact tests can be effectively used to detect early damage on slabs using this proposed parameter.

This paper aims to characterize community archives in the common array of the manuscript collection of the National Library of Russia (NLR). The purpose of the paper is to identify the features of organization of the archival system of Russia and the place of community archives in it. The authors intend to characterize the features of origin, history of existence and preservation of archives of public organizations in Russia on the example of the archives of Russian societies of the nineteenth and twentieth centuries; to spread knowledge about historical communities of Russia and their archival heritage and to discuss the value of community archives and their information potential.

The research is based on the traditional methodology of the academic archival studies. At the same time interdisciplinary approach plays a great role in the field of study of community archives. The findings of the study were obtained as a result of the application of methods of historical research and special historical disciplines: archival heuristics, archive studies, source studies and archeography. The data were complemented by documentary analysis, including materials of nine archives, documents concerning acquisition and storage of these archives.

As a result of the study of different community archives in the Manuscript Department of the NLR the authors came to the conclusion about poor preservation and diffusion of these archives. It suggests the necessity of developing methods of virtual archive reconstruction.

This is the first study to date on the community archives in Russia. The first attempt to attribute and classify community archives of the NLR.