Evaluation of Nine Semi-pilot Scale Whey Pretreatment Modifications for Producing Whey Protein Concentrate

Cheese whey was chemically pretreated and subjected to one of nine semi-pilot scale, physical pretreatment modifications involving various combinations of centrifugal clarification (CC) and/or microfiltration (MF) to remove residual lipids and phospholipoprotein complexes. Two pretreatment modifications were most effective for producing whey with least turbidity and lowest lipid and phospholipid contents. Whey given these two pretreatments provided highest ultrfiltration (UF) membrane flux rate and upon drying of the UF retentate resulted in the most highly functional WPCs in terms of solubility, foam expansion, emulsifying activity and gelation.     

Heating energy savings potential from retrofitting old apartments with an advanced double-skin façade system in cold climate

Apartments account for over 60% of total residential buildings and consume a significant portion of primary energy in South Korea. Various energy efficiency measures have been implemented for both new apartment constructions and existing apartment retrofits. Old apartment structures have poor thermal performances, resulting in a high energy consumption. The South Korean government initiated retrofitting projects to improve the energy efficiency in old apartments. Apartment owners typically replace old windows with high-performance windows; however, there is still a demand for better and more innovative retrofit methods for a highly improved energy efficiency. This paper proposes an advanced double-skin façade (DSF) system to replace existing balcony windows in old apartments. Considering the cold climate conditions of Seoul, South Korea, it mainly discusses heating energy savings. Three case models were developed: Base-Case with existing apartment, Case-1 with typical retrofitting, and Case-2 with the proposed DSF system. The EnergyPlus simulation program was used to develop simulation models for a floor radiant heating system. A typical gas boiler was selected for low-temperature radiant system modeling. The air flow network method was used to model the proposed DSF system. Five heating months, i.e., November to March, and one representative day, i.e., January 24, were selected for detailed analysis. The main heat loss areas consist of windows, walls, and infiltration. The results reveal that the apartment with the DSF retrofit saves 38.8% on the annual heating energy compared to the Base-Case and 35.2% compared to Case-1.     

Relationship of multidrug-resistant gene and extended-spectrum carbapenem-resistance in <i>Staphylococcus aureus</i>

The aim of this study was to determine the relationship between phenotypic antimicrobial susceptibilitypatterns and extended-spectrum, carbapenem-resistance genes. A total of 109 clinical Staphilococcus aureus strains weresubjected to 19 antimicrobial susceptibility tests. Resistance to methicillin (mecA), penicillin (blaTEM), and tetracycline(tetM) was detected. We compared the presence of the blaTEM genes with extended-spectrum, carbapenem-relatedgenes and identified the types of SCCmec genes. Of 109 clinical S. aureus strains, 62 (56.88%) had methicillin resistanceand 60 strains carried mecA. The prevalence of blaTEM and tetM genes was 81.65% and 37.61%, respectively. The mostpredominant SCCmec type was SCCmec type II 28/60 (46.67%), in 60 mecA-positive methicillin-resistant S. aureus(MRSA) isolates. The SCCmec prevalence rates were type IVA 30.00% (18/60), type IVb 8.33% (5/60), type IVd 6.67%(4/60), and non-typable 8.33% (5/60). Sixty of the 109 (55.05%) MRSA isolates were positive for extended-spectrumcarbapenems (31/60) (51.67%), cephalosporins 40/60 (66.67%) and carbapenems 31/60 (51.67%). The predominantSCCmec type II demonstrated more carbapenem-resistance than the IVA, IVb and IVd types.     

Advances in J‐integral estimation of circumferentially surface cracked pipes

This paper describes enhanced J‐integral estimation schemes for pipes with circumferential semi‐elliptical cracks subjected to tensile loading, global bending and internal pressure. These schemes are given in two different forms to cover the wide ranges of geometries and material parameters; the modified GE/EPRI method and the modified reference stress method. In the former method, new plastic influence functions for fully plastic J‐integral estimation are developed based on extensive three‐dimensional finite element calculations. In the latter method, new optimized reference loads are suggested and utilized to predict the J values. To verify the feasibility of these two schemes, J‐integral values obtained from further detailed FE analyses are compared to those from the proposed schemes. Because the estimated J‐integrals agree fairly well with the detailed FE analysis results, the new solutions can be applied for accurate structural integrity assessment of different size pipes with a circumferential surface crack.     

Process plan selection based on product mix and production volume

Most shops currently maintain a single process plan for each part type manufactured by the shop even when multiple process plans are feasible to produce the part. The use of a static process plan for a part regardless of the product mix and volume robs the shop of production flexibility and efficiency. In this paper, given that multiple process plans for a part exist, a method to determine the best process plan to implement for a part type in a given production scenario defined by a known product mix and volume is addressed. The method selects a set of process plans to implement based on minimizing total material handling and machining time for the part mix and volume. The problem is modelled mathematically and solved using a heuristic algorithm. Experimental results to describe the performance of the algorithm are presented for different production scenarios, problem sizes, and solution strategies.     

Flexible guidepath design for automated guided vehicle systems

We address the problem of unidirectional guidepath layout design for automated guided vehicle systems- A two-step layout design method to consider both loaded and empty vehicle movements is developed to guarantee a complete layout design. First, the flow path selection (FPS) problem is formulated to design guidepath layout with the objective of minimizing loaded vehicle movements. Both a mathematical model and a heuristic algorithm for FPS are presented. Since AGV guidepath layouts are used by both loaded and empty vehicles, the FPS does not guarantee a closed or complete layout design. For the case when an incomplete or unclosed layout is produced from the first step, a complementary layout design (CLD) approach to convert the incomplete layout into complete one with the consideration of empty vehicle movements is considered in the second step. A heuristic for the CLD problem is developed. An example problem is used to illustrate the whole design approach.     

Flux Optimization During Tapping in BOF Process

An integrated Plate Mill has started it’s operation on July 7, 2010 in Gwangyang Steelworks, POSCO. The production capability is about 2.5 million tons per year and the main stream consists of Blast Furnace, Hot metal pretreatment (KR), Converter, Bubbling Station, RH/VTD and Continuous Casting. Particularly, it is possible to control sulfur concentration at excellent level in BOF without any further treatment in LF or VTD, which is attained by unique KR process and scrap usage strategy in BOF. In this paper, desulfurization efficiency and steel cleanliness was introduced by optimizing flux amount during tapping in BOF process. In addition, the effect of the flux addition on the refractory of ladle was investigated based on EPMA analyses with the viewpoint of phase diagram. The cleanliness of each sample was examined using optical emission spectrometry and oxygen nitrogen determinator.     

HYDRODYNAMICS OF FLUIDIZATION EFFECT OF PRESSURE

One of the largest concerns when using fluidized beds to commercialize many chemical processes, such as gasification of coal, is scale-up. We believe this is due to the absence of an experimentally verified hydrodynamic theory that can describe the complicated transient gas and solid motion in a fluid bed. During the past few years several organizations began to develop hydrodynamic computer models that promise to be predictive in many respects.

Our present computer model calculates the pressure, the void fraction and the velocities of a single size solid and of the gas. Computed time averaged porosity distributions in two dimensional beds with a Jet at atmospheric pressure agreed with our measurements without the use of any fitted parameters. Photographically determined bubble sizes compared well with the predicted sizes. Calculated gas velocity distributions also agreed with the experimental values measured at westinghouse in a semi-circular bed with a Jet.

In this paper the results of our measurements of time averaged porosities in a steel bed at elevated pressures are compared to our model predictions. We also show that the computed Jet penetrations are close to those reported by IGT in their high pressure fluidized bed. Our calculations also show that the amplitudes of pressure oscillations are much smaller at elevated pressures than at atmospheric pressure. In this sense, the fluidization is smoother at high pressures. An analytical examination of the equations of change in terms of a linearized hyperbolic diffusion equation supports this observation.     

Metformin-induced encephalopathy without lactic acidosis in a patient with contraindication for metformin

A 51-year-old Korean man with end-stage renal disease and who was on intermittent hemodialysis was admitted with progressive dysarthria, gait disturbance, and myoclonus. The liver function tests and the electrolyte and arterial gas analyses were normal. The Magnetic resonance imaging scan showed a diffuse symmetric high signal intensity in the basal ganglia on the T2-weighted image. After a thorough history taking, we knew that he had been treated with metformin for 3 months at other hospital without our hospitals staff's knowledge. After stopping the metformin, the patient's neurologic signs and symptoms disappeared and the Magnetic resonance imaging findings after 20 days were markedly improved.