Comparison of Calculation Methods of Elastic Bonding: Limits of the Gamma Method Using an Example of a Wood–Concrete Composite Floor with Single Loads

Various methods are available for the calculation of timber–concrete composite floors. The gamma method, which is important in construction practice, as well as the differential equation method, are based on the simplified assumption of a continuous bond between wood and concrete. This makes it possible to analytically calculate the internally statically indeterminate partial section sizes and deformation sizes, analogous to the force size method. In this paper, two typical load situations of concentrated loads (central and off-centre) were analytically and numerically evaluated and compared using the above-mentioned methods (gamma and differential equation), with a discrete method for the case of a timber beam reinforced with a concrete slab using screws as fasteners. The calculation results show significant deviations, which speak for the application of discrete methods in certain load situations and thus limit the usability of the gamma method under certain conditions. For the problem of deflection determination, which is not dealt with in the literature for the discrete method, a numerical method is described in the present work, which was first developed and presented by the first author.

Association Between Anthropometric Measurements and the Amount of Fat Aspirated in Waist and Abdominal Liposuction: A 20-year Retrospective Study

Background: Previous studies revealed that larger liposuction volumes were related to an increased risk of complications. However, no concrete data exist to support the most critical factor which affects the liposuction volume in the waist and abdominal area. This study was undertaken to investigate the relationship between the anthropometric measurements and lipoaspirate volume.Methods: The present study was a single-center retrospective study. 742 patients who met the inclusion and exclusion criteria in our hospital, from January 2001 to August 2020, were reviewed. Spearman correlation analyses and multivariable regressions were used to assess the relationship between the anthropometric measurements and lipoaspirate volume. Linear-by-linear association chi-square statistic and Goodman-Kruskal gamma method were used to test the consistency and to develop a rank prediction formula.Results: A total of 742 patients aged 18-59 years old met the inclusion criteria. Among all the anthropometric measurements, the highest correlation coefficient was observed in waist circumference. Subgroup analyses indicated that there was an interaction between the BMI and waist circumference on liposuction volume. Formula was generated to estimate the range of liposuction volume based on the nine grouped waist circumferences [liposuction volume (mean) = 106.3 waist circumference (mean) - 7497, P < 0.001, adjusted R2 = 0.9638].Conclusions: Waist circumference was the most influential factor for lipoaspirate volume. Roughly predicting the lipoaspirate volume allows surgeons to estimate their operating volume even if no iconography machine is available during suction-assisted lipectomy. This can increase safety, potentially decreasing the number of adverse events.

The use of dietary fiber in the technology of minced meat semi-finished products

The production and consumption of meat and meat products in Ukraine are increasing every year. The highest rates are observed in the segment of chilled meat semi-finished products. Manufacturers of chopped semi-finished products use technologies for enriching meat products with dietary fiber, which improve the consumer and technological properties of the product. A comparison of the effects of adding fiber to fat and meat shows that in the case of meat the result is more pronounced. This is due offact that wheat fibers bind water more efficiently, which is released from the meat during heat treatment. The aim of the work was to investigate the effect of dietary fiber Kametsel on the quality indicators of chopped semi-finished products. The material of the research was «Juicy» cutlets from mechanically deboned poultry meat with different amounts of Kametsel additive. The generally accepted methods for determining the organoleptic properties of the product were used. The mass fraction of moisture was determined by the method of drying in a drying oven, and the water-binding capacity (WBC) of minced meat was determined by the Grau-Gamma method. It has been established that the use of dietary fiber Kametsel in the composition of model samples of «Juicy» cutlets improves their consistency and increases their juiciness. The highest product yield 80,31 % was observed for semi-finished products with the highest dietary fiber content. The lowest was at the variant II 71,40%, which is less than the control variant by 7,38%. In the semi-finished products of variant III, the values of moisture were higher by 63,50% and the moisture-binding capacity of minced meat by 61,40%, which is higher than the control samples by 2,20 and 1,80%. Adding Kametsel additive to minced meat is one of the ways to obtain high-quality meat products with controlled properties.

Experimental study and theoretical analysis of glulam-concrete composite beams connected with ductile shear connectors

Ductile shear connectors are often applied in timber-concrete composite beams. The relative interface slip of such kind of composite beams will affect the mechanical performance of the composite beams and result in structural nonlinearity. Gamma method which adopts effective bending stiffness to reflect semi-rigid connection is recommended in Eurocode 5. The effective bending stiffness is irrelevant to external loads and calculation points of the composite beam. However, actual bending stiffness distribution along the beam is variable due to that shear connectors are subjected to different shear force. In order to verify the accuracy of gamma method, four-point bending tests of a total of three glulam-concrete composite beams with lag screw connectors and one pure glulam beam were conducted in this article. The failure mode, bearing capacity, and load–deflection relationship were investigated in the experiment. Meanwhile, push-out tests of composite beams were also conducted for determination of the force–displacement relationship of ductile shear connectors. Then, numerical simulation using beam-truss model was established for investigation on the mechanism of composite beams. Finally, theoretical analysis of composite beams considering the effect of interface slip was also presented. Comparing results from gamma method with the presented method, it is shown that both methods can calculate deflection at serviceability limit state with high precision. However, non-uniform distribution of actual bending stiffness cannot be reflected by gamma method.

Toward a test of the “Law of Crime Concentration” in Japanese cities: a geographical crime analysis in Tokyo and Osaka

This brief report aims to reveal crime concentration at the district level in Tokyo and Osaka, Japan, two cities characterized by low crime rates. Eight types of property crimes that occurred between 2008 and 2017 in Tokyo and Osaka and had been aggregated by the census enumeration district were analyzed using the Gini coefficient based on the Poisson-Gamma method. The results indicated three patterns. First, crime concentration was identified. Second, the degree of concentration depended upon crime type. Commercial burglary was the most concentrated crime type, and theft from vehicle and theft from vending machine were the most dispersed. Third, crime concentration patterns either remained stable or became more concentrated over time. Additionally, while theft of bicycle was found to display stable concentration levels over time, the concentration level of purse snatching was fluid. On the basis of the results, this report discusses the possibility of establishing the “Law of Crime Concentration” (LCC) in two Japanese cities.

Numerical Study of the Geometry Effect of Notched Connections in Mass Timber Panel-Concrete Composite Floors

A mass timber panel-concrete (MTPC) composite floor system consists of a timber panel in the tensile zone, a concrete layer in the compression zone, and shear connectors between timber and concrete. The notched connections that are cut in timber and connected with concrete by the interlocking effect are often classified as the best type of connection system in terms of stiffness and load-carrying capacity. To study the effect of notch geometry to the performance of notched connections and composite beams, 2D finite element models are built in ABAQUS in this study. The concrete portion is modelled with concrete damaged plasticity model while the timber portion is modelled with Hashin’s failure criteria. The effective bending stiffness and ultimate bending capacity of the composite beam under uniformly distributed load are obtained from the finite element models and are compared with the well-known Gamma method in Eurocode 5 and strut-and-tie model. Good agreement between finite element model in the elastic range and strut-and-tie model was achieved. However, due to the assumptions made in the Gamma method, it was found that this simplified design method is not capable of describing MTPC composite floors with discrete notched connections.