Preliminary Characterization of Novel Extra-cellular Lipase from Penicillium crustosum Under Solid-State Fermentation and its Potential Application for Triglycerides Hydrolysis

Current studies about lipase production involve the use of agro-industrial residues and newly isolated microorganisms aimed at increasing economic attractiveness of the process. Based on these aspects, the main objective of this work is to perform the partial characterization of enzymatic extracts produced by a newly isolated Penicillium crustosum in solid-state fermentation. Lipase extract presented optimal temperature and pH of 37?°C and 9?C10, respectively. The concentrated enzymatic extract showed more stability at 25?°C and pH?7. The enzymes kept 100% of their enzymatic activity until 60?days of storage at 4 and ?10?°C. The stability under calcium salts indicated that the hydrolytic activity presented decay with the increase of calcium concentration. The specificity under several substrates indicated good enzyme activities in triglycerides from C4 to C18.     

Incremental forms of Schapery’s model: convergence and inversion to simulate strain controlled ramps

Schapery’s nonlinear viscoelastic model is written in incremental form, and three different approximations of nonlinearity functions in the time increment are systematically analysed with respect to the convergence rate. It is shown that secant slope is the best approximation of the time shift factor, leading to significantly higher convergence rate. This incremental form of the viscoelastic model, Zapas’ model for viscoplasticity, supplemented with terms accounting for damage effect is used to predict inelastic behaviour of material in stress controlled tests. Then the incremental formulation is inverted to simulate stress development in ramps where strain is the input parameter. A comparison with tests shows good ability of the model in inverted form to predict stress–strain response as long as the applied strain is increasing. However, in strain controlled ramps with unloading, the inverted model shows unrealistic hysteresis loops. This is believed to be a proof of the theoretically known incompatibility of the stress and strain controlled formulations for nonlinear materials. It also shows limitations of material models identified in stress controlled tests for use in strain controlled tests.     

金银滴定分析方法一览

叙述了１９９０￣１９９５年国内外Ａｕ、Ａｇ滴定分析的进展，包括新指示剂，新方法与技术等。     

Evidence from 18S ribosomal DNA that the lophophorates are protostome animals

The suspension-feeding metazoan subkingdom Lophophorata exhibits characteristics of both deuterostomes and protostomes. Because the morphology and embryology of lophophorates are phylogenetically ambiguous, their origin is a major unsolved problem of metazoan phylogenetics. The complete 18S ribosomal DNA sequences of all three lophophorate phyla were obtained and analyzed to clarify the phylogenetic relationships of this subkingdom. Sequence analyses show that lophophorates are protostomes closely related to mollusks and annelids. This conclusion deviates from the commonly held view of deuterostome affinity.     

Moisture uptake and resulting mechanical response of biobased composites. I. constituents

The mechanical properties of the biobased fiber and resins have been characterized and moisture influence on the behavior of these materials has been studied. Commercially available biobased thermoset resins (Tribest, EpoBioX, Palapreg, Envirez SA, and Envirez SB) and regenerated cellulose fibers (Cordenka) have been conditioned at different levels of relative humidity (as received, dried, 41, 70, and 90%) to obtain materials with different moisture content. The following properties of polymers were measured: tensile, flexural (3P‐bending), impact strength (unnotched Charpy), and fracture toughness (compact tension). The results of characterization of biobased thermosets were compared against data for epoxy Araldite LY556, which is used as reference resin. RCF bundles (with and without twist, extracted from fabric) as well as single fibers separated from these bundles were tested in tension. In general biobased resins performed well, moreover EpoBioX showed better properties than synthetic epoxy. POLYM. COMPOS., 35:1150–1159, 2014. © 2013 Society of Plastics Engineers     

Non‐binary protograph low‐density parity‐check codes for space communications

Protograph‐based non‐binary low‐density parity‐check (LDPC) codes with ultra‐sparse parity‐check matrices are compared with binary LDPC and turbo codes (TCs) from space communication standards. It is shown that larger coding gains are achieved, outperforming the binary competitors by more than 0.3 dB on the additive white Gaussian noise channel (AWGN). In the short block length regime, the designed codes gain more than 1 dB with respect to the binary protograph LDPC codes recently proposed for the next generation up‐link standard of the Consultative Committee for Space Data Systems. Copyright © 2012 John Wiley & Sons, Ltd.     

Verifying temporal specifications of Java programs

Software Quality Journal - Many Java programs encode temporal behaviors in their source code, typically mixing three features provided by the Java language: (1) pausing the execution for a limited...     

Moisture uptake and resulting mechanical response of bio‐based composites. II. composites

The durability of entirely bio‐based composites with respect to the exposure to elevated humidity was evaluated. Different combinations of bio‐based resins (Tribest, EpoBioX, Envirez) and cellulosic fibers (flax and regenerated cellulose fiber rovings and fabrics) were used to manufacture unidirectional and cross‐ply composite laminates. Water absorption experiments were performed at various humidity levels (41%, 70%, and 98%) to measure apparent diffusion coefficient and moisture content at saturation. Effect of chemical treatment (alkali and silane) of fibers as protection against moisture was also studied. However, fiber treatment did not show any significant improvement and in some cases the performance of the composites with treated fibers was lower than those with untreated reinforcement. The comparison of results for neat resins and composites showed that moisture uptake in the studied composites is primarily due to cellulosic reinforcement. Tensile properties of composites as received (RH = 24%) and conditioned (RH = 41%, 70%, and 98%) were measured in order to estimate the influence of humidity on behavior of these materials. Results were compared with data for glass fiber reinforced composite, as a reference material. Previous results from study of unreinforced polymers showed that resins were resistant to moisture uptake. Knowing that moisture sorption is primarily dominated by natural fibers, the results showed that some of the composites with bio‐based resins performed very well and have comparable properties with composites of synthetic epoxy, even at elevated humidity. POLYM. COMPOS., 36:1510–1519, 2015. © 2014 Society of Plastics Engineers     

Time-dependent properties of graphene nanoplatelets reinforced high-density polyethylene

The deformation of polymers at constant applied stress is one of their major drawbacks, limiting their use in advanced applications. The study of this property using classical techniques requires extensive testing over long periods of time. It is well known that reinforced polymers show improved behavior over time compared to their neat counterparts. In this study, the effect of adding different amounts of graphene nanoplatelets (GNPs) on the time-dependent properties of high-density polyethylene (HDPE) is investigated using short-term creep tests and load/unload recovery tests. The results are discussed in terms of the test profile and the influence of loading history. Viscoplasticity/viscoelasticity analysis is performed using Zapas model and by comparing creep, creep compliance and pure viscoelasticity curves. The results show that the reinforcement of 15 wt% GNP have the most significant effect on the time-dependent behavior, reducing the strain by more than 50%. The creep compliance curves show that nano-reinforced HDPE behaves nonlinearly viscoelastically even at very low stresses. In addition to demonstrating the effect of nano-reinforcement, the discussion of the results concludes that the influence of loading history can be quite significant and should not be neglected in the design and evaluation of material behavior.     

QuicK-means: accelerating inference for K-means by learning fast transforms

Machine Learning - K-means—and the celebrated Lloyd’s algorithm—is more than the clustering method it was originally designed to be. It has indeed proven pivotal to help increase...