Efficiency of wave impeding barrier in pipeline construction under earthquake excitation using nonlinear finite element analysis

Earthquakes have caused colossal casualties and severe damages to engineering structures and especially leading to substantial economic loss to the underground structures and/or infrastructures. Pipelines are one of most important component of lifeline engineering. For instance, the Southern Caucasus- Eastern Turkey energy corridors are formed by several key pipelines carrying crude oil and natural gas from Azerbaijan, via Georgia, to world markets through Mediterranean Sea. Many project accomplished recently and construction of new corridors are still going on. They should be protected from earthquake disaster especially when they pass through high seismicity zones. The installation of wave impeding barriers (WIB) below the vulnerable infrastructures as pipelines established in soft soil can be used to reduce the effect of the earthquake induced ground borne vibrations. In this paper, a WIB as artificial bedrock based on the cut-off frequency of a soil layer over bedrock is proposed as isolation measurement in order to mitigate the dynamic response of the buried pipelines under earthquake strong ground motion. The computational simulation of the wave propagation problem is directly achieved by employing nonlinear 2D finite element modelling for prediction of screening performance of WIB on the dynamic response of vibrating coupled soil-pipeline system. Energy absorbing boundaries along the truncated interfaces of the unbounded nature of the underlying soil media are implemented in the time domain along with Newmark’s integration. An extensive parametric investigation and systematic computations are performed with different controlling parameters. The obtained numerical results point out that WIB can be very promising as an isolator to protect pipelines when they establish for a certain depth.     

The effect of heat treatment and starter culture on colour intensity and sensory properties of Kulek cheese

The effect of the heat treatment on colour intensity and sensory properties of Kulek cheese made from raw milk with (RS) or without starter culture (R) and heated milk with starter culture (HS) was investigated during ripening. Colour L, a and b values of Kulek cheeses were determined for both interior and surface. The values for cheese R were 82.4 and 74.5 for L, ?5.2 and ?5.5 for a, 31.0 and 34.7 for b interior and surface respectively. The equivalents for RS cheese were 82.8 and 75.7 for L, ?4.8 and ?5.0 for a, 31.0 and 34.0 for b. The values for HS cheese were 88.9 and 88.4 for L and ?3.3 and ?3.3 for a, 22.8 and 24.2 for b. L values (lightness) were the highest in cheeses made from heated milk while b and negative a values were the highest in cheeses made from raw milk. Aroma scores of raw and heat‐treated milk cheeses made with starter were not significantly different. The panelists scored cheeses made from raw milk without starter as the best in body and texture.     

EFFECT OF LIPASE ENZYME ON THE RIPENING OF WHITE PICKLED CHEESE

The effect of addition of pregastric lipase enzyme on the accelerated ripening of white pickled cheese was investigated. Commercial pregastric lipase was added to milk before rennet addition at a level of 0,5, 8, 11 g per 100 L of milk and cheeses were made from this milk. Total solids, fat, total nitrogen, salt, titratable acidity, pH and free fatty acids (C₂-C_18:1) were analysed in the samples during 1–90 days of ripening period at 15 days intervals. Total solids, fat, total nitrogen, salt, titratable acidity, and pH of cheeses slightly increased during the ripening period. Free fatty acids and volatile free fatty acid contents in cheeses made from pregastric lipase added milk were affected by pregastric lipase and their contents were increased significantly (P<0.01) during the ripening period. Particularly, when cheese had a high level (11 g per 100 L milk) pregastric lipase, the amounts of butyric, caproic and caprylic acids in white pickled cheese were quite high. The relative amounts of volatile free fatty acids varied with storage time and pregastric lipase levels.     

Biocomposites from polyhydroxybutyrate and bio-fillers by solvent casting method

Biocomposites from polyhydroxybutyrate (PHB) and some bio-fillers such as lignin (L), alpha cellulose (AC) and cellulose nanofibrils (CNFs) were prepared to investigate the effect of the bio-fillers on the properties of PHB by a solvent casting method. The thermal properties by thermogravimetry analysis (TGA–DTG and DTA) and differential scanning calorimetry (DSC) were determined; morphological characterization by scanning electron microscopy (SEM) and structural analysis by X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) of the biocomposites were performed. TGA curves showed that the highest values for T _10%, T _50% of the biocomposites were 278.2^°C for PHB+2%AC and 291.7^°C for PHB+2%CNFs; however, the best value for T _75% was obtained as 381.5^°C for PHB+2%L. According to DTG curves, the best results were found for PHB+0.5%L and PHB+0.5%CNFs. DTA showed an increase in temperature of maximum degradation with loading of lignin and CNFs. The addition of bio-fillers increases T _c and T _m for both first cooling/heating and second cooling/heating. T _c and T _m values for first cooling/healing were found to be lower as compared with second cooling/healing. Furthermore, the addition of bio-fillers acts as a nucleating agent in PHB and SEM pictures showed the porous structure in all biocomposites. SEM images revealed uniform distribution of the reinforcing particles in the polymer at low loadings (0.5 wt%), while higher loadings (2 wt%) of L and CNFs contributed to easy aggregation within the PHB matrix. In XRD studies, PHB in the range 5–55^° shows 6 main peaks. XRD patterns of the PHB biocomposites revealed 3 main peaks at 13.57^°, 16.87^° and 22.1^°, and the other peaks disappeared in the patterns. The largest and lowest values of X _c were found for PHB+2%AC and PHB+2%CNFs, respectively.     

Age-dependent business failures in the US construction industry

Age-dependent failure in the construction industry is explored over two 11-year periods (1973–1983 and 1984–1994) by analysing the age distribution of failed construction companies in each year and computing age-specific failure probabilities over a 10 year period (1985–1994). The conflicting perspectives of organizational theory are reconciled by taking advantage of the complementary nature of the adaptationist and organizational ecology theories while the effects of the characteristics of the construction industry are also considered. The research findings reveal an age-dependent business failure pattern in the US construction industry where the risk of failure increases initially with increasing age, reaches a peak point and decreases thereafter as companies grow older. Newness of a construction company which implies lack of organizational learning and lack of legitimacy, appears to be the main factor explaining this pattern.     

The effects of lipase‐encapsulating carriers on the accelerated ripening of Kashar cheese

In this study, lipase enzymes were encapsulated in κ‐carragenan, gellan and sodium alginate using emulsion and extrusion techniques and were then added to cheese milk together with rennet. The effects of the encapsulating material and ripening period on the chemical, textural and sensory characteristics of Kashar cheese were investigated. The study demonstrated that sodium alginate, gellan and κ‐carrageenan could successfully be used as lipase carrier systems to accelerate the fat breakdown process during the ripening of Kashar cheese. Those samples treated with κ‐carrageenan capsules showed the highest rate of lipolysis and proteolysis compared to those treated with the other capsules.     

Influence of different exopolysaccharide-producing strains on the physicochemical, sensory and syneresis characteristics of reduced-fat stirred yoghurt

Reduced-fat stirred yoghurts were prepared by using ropy and nonropy exopolysaccharide (EPS)-producing strains or nonexopolysaccharide-producing strains. Yoghurts were evaluated for pH, titrable acidity, acetaldehyde, whey separation, viscosity, EPS concentration, sensory and microbiological analyses. Determinations of these parameters were made at 1, 7, 14 and 21 days of storage. Reduced-fat yoghurts made with EPS⁺ strains exhibited lower syneresis and acetaldehyde contents, but higher viscosity than those made with the EPS ⁻ strain. Physico-chemical results correlated with the sensory results in that panellists scored the EPS⁺ yoghurts as having an overall better mouthfeel, but a worse flavour than EPS ⁻ yoghurt.