On the deformation of bimetal wires by drawing

In this study the bimetal wire drawing process is investigated both experimentally and theoretically. Three coating materials, namely copper and the brasses Ms63 and Ms70 are considered in combination with steel St37 wire core. This paper explores some of the unusual effects of the lubrication when drawing a steel wire clad with soft copper. This is explained and discussed using both force equilibrium equations of a generalized deformation mode as well as experimental measurements of the drawing force, strains and microhardness of each constituent of the bimetal wire.     

Oncogenic NRAS Accelerates Rhabdomyosarcoma Formation When Occurring within a Specific Time Frame during Tumor Development in Mice

In the Ptch+/- mouse model for embryonal rhabdomyosarcoma (ERMS), we recently showed that oncogenic (onc) H-, K- or NRAS mutations do not influence tumor growth when induced at the advanced, full-blown tumor stage. However, when induced at the invisible ERMS precursor stage at 4 weeks of age, tumor development was enforced upon oncHRAS and oncKRAS but not by oncNRAS, which instead initiated tumor differentiation. These data indicate that oncRAS-associated processes differ from each other in dependency on the isoform and their occurrence during tumor development. Here, we investigated the outcome of oncNRAS induction at an earlier ERMS precursor stage at 2 weeks of age. In this setting, oncNRAS accelerates tumor growth because it significantly shortens the ERMS-free survival and increases the ERMS incidence. However, it does not seem to alter the differentiation of the tumors. It is also not involved in tumor initiation. Together, these data show that oncNRAS mutations can accelerate tumor growth when targeting immature ERMS precursors within a specific time window, in which the precursors are permissive to the mutation and show that oncNRAS-associated processes differ from each other in dependency on their occurrence during tumor development.     

Nonisothermal crystallization kinetics of PLA/nanosized YVO4 composites as a novel nucleating agent

The influence of nanosized YVO₄ particles as a novel and efficient nucleating agent on the nonisothermal crystallization behaviors of poly(lactic acid) (PLA) was studied. A modified Avrami model was utilized to describe the nonisothermal crystallization kinetics of pure PLA and PLA nanocomposites. The differential isoconversional Friedmann formula was employed to calculate the effective activation energies (E_X(t) ) of nonisothermal crystallization from the glass state. The results showed that modified Avrami methods describe the nonisothermal crystallization kinetics of pure PLA and PLA nanocomposites well. The crystallization rate of PLA/1 mass% YVO₄ was faster than that of pure PLA sample by factor 5 × 10³ at a heating rate of 1 K min⁻¹. While the values of Lauritzen–Hoffman parameters (K_g and U*) of the PLA/YVO₄ nanocomposites were lower than those of pure PLA, indicating the nucleation efficiency of nanosized YVO₄ particles for PLA. Scanning electron microscopy images reflect the uniform dispersion of 1 mass% YVO₄ in PLA matrix. Thermogravimetric analysis results revealed that the thermal degradation parameters are slightly lowered by 7 °C on increasing the mass percentage of YVO₄ in the PLA nanocomposites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48340.     

Some functional properties of oilseed proteins

Oilseeds have potential food uses because of their high protein content. Besides, these proteins when added to a type of foods, supply desirable functional properties, such as whipping capacity and viscosity, emulsification and water and oil holding capacities. Rapeseed and soybean protein isolates were found to possess whipping capacity followed by those of sunflower, peanut, sesame, cottonseed and safflower. The addition of sugar improved the whipping properties of oilseed proteins. The whipping capacity of oilseed proteins decreased due to heating at 100 degrees C for time of 15 to 60 min. Soybean protein had the highest emulsifying capacity compared with the other oilseed proteins. The heated oilseed proteins had emulsification properties similar to or better than the control. Glandless cottonseed protein had high water and oil holding capacities. The water holding capacity of oilseed proteins decreased gradually as the duration of heating at 100 degrees C was increased. On the other hand the heated oilseed proteins had oil holding capacities similar to or better than unheated proteins.     

Electron beam synthesis and characterization of poly(vinyl alcohol)/montmorillonite nanocomposites

Poly(vinyl alcohol) (PVA)/montmorillonite clay (MMT) nanocomposites in the form of films were prepared under the effect of electron beam irradiation. The PVA/MMT nanocomposites gels were characterized by X‐ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and mechanical measurements. The study showed that the appropriate dose of electron beam irradiation to achieve homogeneous nanocomposites films and highest gel formation was 20 kGy. The introduction of MMT (up to 4 wt %) results in improvement in tensile strength, elongation at break, and thermal stability of the PVA matrix. In addition, the intercalation of PVA with the MMT clay leads to an impressive improved water resistance, indicating that the clay is well dispersed within the polymer matrix. Meanwhile, it was proved that the intercalation has no effect on the metal uptake capability of PVA as determined by a method based on the color measurements. XRD patterns and SEM micrographs suggest the coexistence of exfoliated intercalated MMT layers over the studied MMT contents. The DSC thermograms showed clearly that the intercalation of PVA polymer with these levels of MMT has no influence on the melting transitions; however, the glass transition temperature (T_g) for PVA was completely disappeared, even at low levels of MMT clay. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1129–1138, 2006     

Studies on the Possibility of Producing Fats from Food Wastes by Using Micro-Organisms. II Physical and Chemical Properties of Fat Produced from Different Fungi

The physical and chemical characteristics of fat produced by microorganisms depends on strain of microbes, growth conditions, structure of media, etc. Therefore, the consumption of the produced fat in human nutrition and useful industries is dependent on its chemical, physical and toxical properties. The physical properties of fats produced from Aspergillus niger, Aspergillus oryzae, Penicillium roqueforti and Rhizopus arrhizus including melting point, refractive index and specific gravity were studied. Chemical properties such as fat constants, acid number, peroxide value, saponification value and iodine value, fat composition and fatty acid composition for each oil were also investigated.     

CORROSION FATIGUE OF STEEL IN VARIOUS AQUEOUS ENVIRONMENTS

Abstract— Corrosion fatigue of three steels namely: AISI 1018, AISI 4340 and 17–7 PH stainless steel are investigated in various environments. Testing mediums chosen are natural seawater, polluted sea water from an industrial site, drinking tap water produced by desalination process, 4% sodium chloride tap water solution and a laboratory air environment. Results obtained for the three steels are consistent in pointing out that pollutants in seawater do not contribute to an acceleration of corrosion fatigue. The aggressiveness of drinking water is attributed to its chemical instability, low alkalinity and bicarbonate content.     

Studies on the formation of alpha-amylase by Thermomonospora vulgaris

Conditions affecting the formation of alpha-amylase by static cultures of the thermophilic actinomycete Thermomonospora vulgaris were studied. The organism failed to grow under submerged culture conditions or when the culture medium was devoid of CaCO3-alpha-Amylase was produced during the logarithmic phase of growth and maximum yield was obtained after 3 to 9 days of incubation. Growth and amylase formation took place only in a range from 45 degrees to 55 degrees C; optimum temperature was 55 degrees C. Of the tested carbon sources only starch induced enzyme formation. Maximum enzyme yield was obtained when starch concentration of the medium was 2% and when ammonium citrate served as a nitrogen source. Crushed clay pots could substitute for CaCO3 of the medium, but growth and amylase yield were less.     

An approach to predict free surface fracture in bulk forming

This work presents a unified approach to predict surface strains at failure in bulk forming processes. The approach does not deal with a specific process but rather with prescribed strain and stress paths. The material to be processed is assumed to possess an initial void volume fraction that grows and colaesces with straining, ending by fracture. The predictions are based on a formulation for voided solids according to the Gurson-Tvergaard yield function adapted to include orthotropic anisotropy. The incident of fracture is characterized by shear band formation within the ligaments of the matrix material among spheroidal voids as described by McClintock. The results are represented by a straight line plot of tensile limit strain versus the compressive strain for different loading paths. These limit curves are shown to be dependent on the initial void fraction, hardening, and anisotropy of the matrix matrial. Alloys with lower initial void fractions as well as those of higher hardening show better workability. The model is applied to predict bulk formability curves for steels AISI 1040 and 1045, Aluminum AI 7075-T6, and copper, based on the proper selection of micromechanical parameters for these alloys. The validity of the model is ensured through fairly favorable comparison with experimentally determined limit curves. The current failure conditions are suitable to predict the experimental dual slope fracture line that may exist for some alloys such as cold-drawn steel AISI 1045 and aluminum 2024-T6 by considering two mechanisms of failure: internal necking in the ligament material between voids, followed by transition to shear band formation.