Thermodynamic assessment of integrated heat recovery system combining exhaust-gas heat and cold energy for LNG regasification process in FSRU vessel

A thermodynamic assessment of an integrated heat recovery system, which simultaneously recovers both the cold energy of LNG released into seawater and the exhaust gas heat of diesel generator released into ambient air during the regasification process in a LNGFSRU vessel, has been carried out. For the LNG regasification unit consisting of two-stage heat exchangers, a primary Rankine cycle was applied as a typical power cycle of the type A for recovering cold energy to the first-stage heat exchanger. A secondary Rankine cycle of the type B was serially inserted between the first-stage and the second-stage heat exchangers for recovery of the remaining cold energy of preheated LNG. Then, in the type C, the exhaust gas, which had a relatively high temperature, was applied as the heat source of the secondary Rankine cycle, instead of seawater. In such a sequential procedure, the type C was finally suggested as an integrated heat recovery system, in which the seawater and exhaust gas were combined as the heat sources. When the net outputs produced from each heat recovery system were maximized by changing the pressure and mass flow rate of working fluid, the thermal efficiency of the integrated heat recovery system of the type C was η[subscript I,EG] = 0.0741. The results showed an improvement of approximately 13.3% (25.6%) in the thermal efficiency compared to the value of η[subscript I,SW] = 0.0654 ( η[subscript I] = 0.0590) for the conventional cold energy recovery system of the type B (the type A), which only used seawater as the heat source. Based on this finding, a possibility of utilizing the integrated heat recovery system with the combined cycle within the LNG-FSRU was confirmed.Ministry of Land, Tranport and and Maritime Affairs (Korea) (LNG Plant R&D center

Surgical Management of Coexisting Coronary Artery and Valvular Heart Disease

Purpose: Combined coronary artery bypass (CAB) and valve surgery is one of the most challenging surgical procedures, but the operative results have improved over the years. Materials and Methods: From 1989 through 2004, combined CAB and valve operations were performed in 125 patients. Mean age was 63 years, and 86 patients were male. Forty-six patients were diagnosed with coronary artery disease during preoperative evaluation for valvular heart disease (VHD). All patients underwent CAB, and one or more underwent valve replacement or repair (mitral: 54, aortic: 61, tricuspid: 3, DVR: 7) simultaneously. Results: Mean number of distal graft was 1.98 ± 1.07, and LIMA was used in 68 % of patients. Early mortality occurred in 6 patients (4.8%), and the causes were heart failure (4) and sepsis (2). Mean follow-up duration was 91.4 ± 40.9 months (range: 47-245), and late mortality occurred in 4 patients. Kaplan Meier estimated survival rates at 1, 5, and 10 years were 94.4 %, 92.3%, and 89.9%, respectively. Conclusion: Combined coronary and valve operations can be performed safely with optimal surgical results. Although the surgical mortality of coexisting coronary and VHD is higher than either isolated coronary or valvular operations, it may not affect the long-term survival

Lateral Orbitofrontal Gray Matter Abnormalities in Subjects with Problematic Smartphone Use

Background and aims: Smartphone use is becoming commonplace and exerting adequate control over smartphone use has become an important mental health issue. Little is known about the neurobiology underlying problematic smartphone use. We hypothesized that structural abnormalities in the fronto-cingulate brain region could be implicated in problematic smartphone use, similar to that has been reported for Internet gaming disorder and Internet addiction. This study investigated fronto-cingulate gray matter abnormalities in problematic smartphone users, particularly those who spend time on social networking platforms. Methods: The study included 39 problematic smartphone users with excessive use of social networking platforms via smartphone and 49 normal control male and female smartphone users. We conducted voxel-based morphometric analysis with diffeomorphic anatomical registration using an exponentiated Lie algebra algorithm. Region of interest analysis was performed on the fronto-cingulate region to identify whether gray matter volume (GMV) differed between the two groups. Results: Problematic smartphone users had significantly smaller GMV in the right lateral orbitofrontal cortex (OFC) than healthy controls, and there were significant negative correlations between GMV in the right lateral OFC and the Smartphone Addiction Proneness Scale (SAPS) score, including the SAPS tolerance subscale. Conclusions: These results suggest that lateral orbitofrontal gray matter abnormalities are implicated in problematic smartphone use, especially in social networking platform overuse. Small GMV in the lateral OFC was correlated with an increasing tendency to be immersed in smartphone use. Our results suggest that orbitofrontal gray matter abnormalities affect regulatory control over previously reinforced behaviors and may underlie problematic smartphone use

Joint Link Scheduling and Routing for Load Balancing in STDMA Wireless Mesh Networks

In wireless mesh networks, it is known to be effective to use a TDMA based MAC than a contention-based CSMA. In addition, if spatial TDMA is used, network performance can be improved further because of its spatial reuse effect. However this scheme still has a disadvantage in the system performance aspect without a load-balanced routing because the resource of links that are not used is wasted and frequently used links are out of resources. That is, the number of available flows in network is limited because load balancing is not performed. In this paper, we propose joint link scheduling and routing through a cross-layer scheme. For this, we propose a load balancing routing method to maximize available resources under the given traffic pattern and scheduling method for maximizing link utilization on the given route. These two methods are iterated until an optimized solution can be obtained. The proposed algorithm can be formulated using a mathematical LP problem and we show that it is very effective for load balancing compared to simple adoption of IEEE 802.11s which is a standard TDMA protocol in wireless mesh network. If the proposed algorithm is applied to initial design solution such as Smart Grid, the number of available flows can be increased and the load on each link can be balanced

Comparative analysis of outcomes after multiport and single-port laparoscopic colectomy in emergency situations: Is single-port laparoscopic colectomy safe and feasible?

SummaryBackground/ObjectiveAlthough consensus has been reached on the superiority of laparoscopy for a majority of conditions underlying acute abdominal pain, the safety and feasibility of single-port laparoscopic colectomy (SPLC) in emergency situations have not been determined.MethodsA prospective electronic database of all emergency patients who underwent either multiport laparoscopic colectomy (MPLC) or SPLC between April 2006 and December 2014 was used to compare the surgical outcomes of these operative methods.ResultsDuring the study period, 31 MPLCs and 76 SPLCs were performed. These two operative methods resulted in similar operating times, transfusion amounts, lengths of stay, postoperative complications, attainment of lymph nodes, and proximal and distal cut margins. However, the SPLC group had a shorter time to first flatus (2.8±1.9 days vs. 3.8±1.5 days, p=0.005), earlier reinitiation of free oral fluids (3.2±2.1 days vs. 4.4±1.8 days, p=0.002), and lesser requirement of narcotic analgesics (2.5±3.9 times vs. 4.7±4.8 times, p=0.017).ConclusionSPLC could be a safe and effective alternative to MPLC, even in emergency situations when performed by surgeons who have overcome the learning curve associated with single-port laparoscopic techniques. The tendency toward earlier returns to bowel function and decreased incidence of postoperative analgesic use would be potential benefits of SPLC in emergency situations

A Case Study on Safe Blast Design with Vibration Analysis

Safe delicacy blasting is necessarily to decrease safe problems resulting from blasting but if designs to consider only safety, it is a problem not to ensure economical gains because the effect of blasting is decreased. Therefore, blasting vibration must be predicted to consider given circumstances and ground conditions before blasting work, and then a design based on predicted result must be done. In this study, the testing blasting was carried out in two fields within a country, and then measured data for testing blasting were collected. The effect for blasting vibration was analyzed as the property of distance, charging gunpowder capacity, surrounding conditions, and measured points. The test results were performed by back-analysis, and compared with previous research results. Therefore, it will be proposed an effective prediction and design

Subcutaneous Sacrococcygeal Myxopapillary Ependymoma in Asian Female:A Case Report

Subcutaneous sacrococcygeal myxopapillary ependymoma is extremely rare tumor that has a tendency to develop in children and adolescents. There have been several case reports and sporadic reports in the literature. However, no case has been reported in an Asian patient, to the best of our knowledge. We describe a 25-year-old Asian female patient with a subcutaneous sacrococcygeal myxopapillary ependymoma that had been clinically diagnosed as a pilonidal cyst. The tumor was treated successfully by surgical excision and the patient is doing well without evidence of local recurrence or distant metastasis at 2 years after surgery.