AWJ machinability performance of CS/UPR composites with the effect of chemical treatment

This work focuses on the effect of chemical treatment of coconut sheath/unsaturated polyester (CS/UPR) composite on the performance of abrasive waterjet machining (AWJM). Two different chemical treatments, namely alkali (NaOH) and trichlorovinylsilane, were imposed on the CS fiber. Further, the induced compressive strength arising as a result of AWJM was studied along the radial and depth directions of the composite. Experimental results revealed significantly lower induced stress at all points compared to the ultimate stress of CS/UPR composites except the free-edge loading condition. The chemically treated composites also exhibited inconsistent results in the machining characteristics such as kerf taper angle (T_a) and surface roughness (R_a) under varying cutting conditions. However, no direct correlation was seen between interfacial adhesion and T_a and R_a of the cutting zone. The maximum decrease of 12% of T_a and 22% of R_a was found for silane-treated composites compared to the untreated ones. In addition, the composite failure mechanisms such as fiber pullout, fiber breakage, interfacial debonding, matrix failure, and voids were identified in the cutting surfaces through scanning electron microscopy analysis.     

High-pressure destruction kinetics of Clostridium sporogenes ATCC 11437 spores in milk at elevated quasi-isothermal conditions

The high-pressure sterilization establishment requires data on isobaric and isothermal destruction kinetics of baro-resistant pathogenic and spoilage bacterial spores. In this study, Clostridium sporogenes 11437 spores (10⁷ CFU/ml) inoculated in milk were subjected to different pressure, temperature and time (P, T, t) combination treatments (700–900 MPa; 80–100 °C; 0–32 min). An insulated chamber was used to enclose the test samples during the treatment for maintaining isobaric and quasi-isothermal processing conditions. Decimal reduction times (D values) and pressure and temperature sensitivity parameters, Z_T (pressure constant) and Z_P (temperature constant) were evaluated using a 3 × 3 full factorial experimental design. HP treatments generally demonstrated a minor pressure pulse effect (PE) (no holding time) and the pressure hold time effect was well described by the first order model (R² > 0.90). Higher pressures and higher temperatures resulted in a higher destruction rate and a higher microbial count reduction. At 900 MPa, the temperature corrected D values were 9.1, 3.8, 0.73 min at 80, 90, 100 °C, respectively. The thermal treatment at 0.1 MPa resulted in D values 833, 65.8, 26.3, 6.0 min at 80, 90, 95, 100 °C respectively. By comparison, HP processing resulted in a strong enhancement of spore destruction at all temperatures. Temperature corrected Z_T values were 16.5, 16.9, 18.2 °C at 700, 800, 900 MPa, respectively, which were higher than the thermal z value 9.6 °C. Hence, the spores had lower temperature sensitivity at elevated pressures. Similarly, corrected Z_P values were 714, 588, 1250 MPa at 80, 90, 100 °C, respectively, which illustrated lower pressure sensitivity at higher temperatures. By general comparison, it was concluded that within the range operating conditions employed, the spores were relatively more sensitive to temperature than to pressure.     

Effect of High Pressure Treatment and Degree of Milling on Gelatinization and Structural Properties of Brown Rice

Brown rice (BR), medium-milled rice (MR), and fully milled white rice (WR), with different degrees of milling (DOM), 0, 6.6, and 10.4 %, respectively, were high pressure (HP) treated at 200 to 500 MPa for 5 to 15 min. Water absorption, swelling, and gelatinization properties, and microstructural changes were investigated. HP treatment (≥200 MPa) or partial milling (DOM 6.6 %) resulted in water absorption comparable with that of white rice. Swelling behavior was affected by milling and processing temperature. Both HP treatment and milling promoted gelatinization properties. In addition, partial milling reduced the pressure resistance of rice grain, while differences in water absorption, swelling behavior, and gelatinization properties due to milling were reduced by HP treatment. Further, the degree of gelatinization (DG) increased with HP treatment with 400 MPa and 10 min defined as the threshold values for pressure and holding time, respectively. DG values, observed with 400 MPa-10 min treatments, were 41.2, 50.2, and 39.9 %, respectively for BR, MR, and WR. Results demonstrated that HP treatment, combined with milling, is technically feasible and produces rice and rice flour with enhanced DG and swelling behavior. These basic data can be used to improve the processing efficiency and quality of brown rice-based product.     

Pressure Degradation Kinetics of Anthocyanin Pigment and Visual Color of Chinese Bayberry Juice

Pressure degradation kinetics of the anthocyanin pigment content and visual color (L, a, and b values) of Chinese bayberry juice were evaluated at selected pressures (400, 500, and 600 MPa) and holding times (5–10 min). Results indicated that the degradation of anthocyanin content after high pressure processing and during storage followed the first-order models, as well as the change of a and L × a × b values after high pressure processing. The activation energies (V_a) for anthocyanin content, a and L × a × b changes after high pressure processing were –19.845, –14.915, and –12.908 cm³ mol^–1, respectively. V_a analysis indicated that anthocyanin was more pressure sensitive than visual color parameters.     

Enhanced destruction of spoilage microorganisms in apple juice during continuous flow microwave heating

Destruction kinetics of two selected spoilage microorganisms, Saccharomyces cerevisiae and Lactobacillus plantarum in apple juice were evaluated under continuous flow microwave heating conditions and compared with conventional batch heating in a water bath. Inoculated apple juice was heated in a microwave oven (700 W, 2450 MHz) under continuous-flow conditions to selected exit temperatures (52.5–65°C). Aliquots of inoculated juice were also subjected to batch thermal treatments (50–80°C) in a well-stirred water bath. Time-temperature profiles obtained both during heating and cooling of test samples were used to correct both come-up and come-down times. The time-corrected D-values under microwave heating were 4.8, 2.1 and 1.1 s at 52.5, 55 and 57.5°C, respectively, for S. cerevisiae and 14, 3.8 and 0.79 s at 57.5, 60 and 62.5°C, respectively, for L. plantarum with corresponding z-values of 7 and 4.5°C. D-values under batch thermal heating were 58, 25, 10 and 1.9 s at 50, 55, 60 and 70°C, respectively, for S. cerevisiae and 52, 22, 8.4 and 1.2 s at 55, 60, 70 and 80°C, respectively, for L. plantarum with corresponding z-values of 13.4 and 15.9°C. Microbial destruction thus occurred much faster under microwave heating than under thermal heating suggesting some contributory enhanced effects to be associated with microwave heating.     

Short communication: Consumer evaluation of milk high in conjugated linoleic acid

A consumer evaluation was undertaken to determine whether there were differences in the acceptability of milk from cows fed a control or a fish oil diet. The two treatments included a control diet of a 50:50 ratio of forage-to-concentrate and fish oil added to the control diet with 2% (on dry matter basis) added fat from menhaden fish oil. Milk from cows fed the control or fish oil diet contained 3.31 and 2.58% fat and 0.56 and 2.30 g of total conjugated linoleic acid/100 g of fatty acids, respectively. Consumer evaluation of control and fish oil milks found no difference in acceptability.     

A methodological review on attack and defense strategies in cyber warfare

Cyberspace is an integration of cyber physical system components that integrates computation, networking, physical processes, embedded computers and network monitors which uses feedback loops for controlling the processes where the computations are affected by processes and vice versa. More general, cyber physical systems include all equipments operated on preprogrammed instructions ranging from simple electronic devices to the ultra-modern warfare equipments along with life saving devices. Active cyber-attacks can cause cyber warfare situations by disrupting an entire community of people, which in turn raises an emergency situation to the nation. Thus, cyber warfare is a major threat to the nation at large. In this paper, we analyze the various aspects of cyber warfare situations and a survey on ongoing attacks, defense and cyber forensics strategies in that field. Internet of Things (IoT) is an emerging computing area which enables Machine to Machine communication in cyber physical systems. An attack on IoT causes major issues to the security on the devices and thus, the various threats and attacks on IoT are analyzed here. Overall monitoring and data acquisition in cyber physical systems is done by Supervisory Control and Data Acquisition systems and are mainly targeted by the attackers in order to leave the cyberspace applications not functioning. Therefore, the various threats, attacks and research issues pertaining to the cyberspace are surveyed in this paper along with a few research issues and challenges that are to be solved in the area of cyber warfare.