The Computerized Design Program for Tunnel Blasting

Abstract In this study, a computer program to design tunnel blasting pattern has been developed. The program consists of two parts; one is for tunnel blasting pattern design and the other is for blasting modeling to estimate the peak particle velocity, the distribution of fragmentation and the excavation damage zone. We modified the design method of tunnel blasting pattern suggested by Langefors because it provided undesirable pattern in blasting practices such as considerably large center cut and too large burden for Vcut as drilling length increased. As a result, the burden and spacing were reduced to practically appropriate amounts. In addition, the correlation between rock mass rate, RMR, and rock constant in blasting, c, was analyzed based on the data collected from twenty three tests of tunnel blasting. It was concluded that the correlation between them was fairly good enough to be applied in cut design. In order to check the validity of the modified methods and their practical applicability, test blasting was carried out at two different tunnel construction sites in Korea. The results were satisfactory in that the average rate of advance was 90% and the overbreak did not cause additional support. Futhermore, the developed program is capable of estimating peak particle velocity by using (a) the existing vibration equations, (b) the vibration equation obtained by test blasting to check out the practical applicability of the designed blasting pattern. Feedback is implemented into the program to adjust the designed blasting pattern and control the vibration

Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89.6 per cent) compared with that in countries with a middle (753 of 1242, 60.6 per cent; odds ratio (OR) 0.17, 95 per cent c.i. 0.14 to 0.21, P <0001) or low (363 of 860, 422 per cent; OR 008, 007 to 010, P <0.001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -94 (95 per cent c.i. -11.9 to -6.9) per cent; P <0001), but the relationship was reversed in low-HDI countries (+121 (+7.0 to +173) per cent; P <0001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0.60, 0.50 to 073; P <0.001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries.Peer reviewe

Global variation in anastomosis and end colostomy formation following left-sided colorectal resection

Background End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods This study comprised an analysis of GlobalSurg-1 and -2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle- and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6·9 per cent) from low-HDI, 254 (15·5 per cent) from middle-HDI and 1268 (77·6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57·5, 40·9 and 35·4 per cent; P < 0·001) and subsequent use of end colostomy (52·2, 24·8 and 18·9 per cent; P < 0·001) in low- compared with middle- and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3·20, 95 per cent c.i. 1·35 to 7·57; P = 0·008) after risk adjustment for malignant disease (OR 2·34, 1·65 to 3·32; P < 0·001), emergency surgery (OR 4·08, 2·73 to 6·10; P < 0·001), time to operation at least 48 h (OR 1·99, 1·28 to 3·09; P = 0·002) and disease perforation (OR 4·00, 2·81 to 5·69; P < 0·001). Conclusion Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone

Effects of supplementing broiler diets with a combination of fermented red ginseng marc powder and red-koji on thigh meat quality of broiler chick during storage

We assessed the effects of supplementing broiler diets with a combination of fermented red ginseng marc powder and red-koji on thigh meat quality of broiler chick during storage. Broilers (n = 120) were randomly assigned to one of two groups: control or treatment with 1% fermented red ginseng marc combined with red-koji. There were four replicates per group, each comprising 15 birds (10 male and 5 female). Neither the dietary supplementation group nor the number of storage days had a significant (p > 0.05) effect on meat pH. However, TBARS, a measure of lipid oxidation, was significantly affected (p 0.05) on the lightness (L*) of meat in group after 1 and 7 day of storage (included T1 group), or redness (a*) of meat in group at 1 through 7 days of storage, whereas the yellowness (b*) of meat in both groups increased significantly (p < 0.05) with an increase in storage duration. Our results suggest that supplementing broiler diets with fermented red ginseng marc combined red-koji powder does not affect meat color, even after storage. We conclude that dietary supplementation with 1% fermented red ginseng powder combined with red-koji can reduce lipid oxidation in broiler thigh meat after 7 days of storage.

Effect of Alum and Liquid Alum on pH, EC, Moisture, Ammonium and Soluble Phosphorus Contents in Poultry Litter During Short Term: a Laboratory Experiment

Aluminum sulfate (alum, [Al2 (SO4)3. 14H2O]) additions to poultry litter can be used effectively as litter amendments, which can lead to greatly reduce ammonia emissions and phosphorus solubility in the poultry industry. However, there are little studies which compare the effects of alum and liquid alum with respect to the enivornmental effects of poultry litter. The goal of this study was to evaluate the effects of alum and liquid alum on pH, EC, moisture, ammonium and soluble phosphorus contents from poultry litter during 3 weeks. The treatments were mixed in the upper 1cm of litter, which included 3.5g alum, 5.5g alum, 7.5g alum, 8g liquid alum, 13g liquid alum, and 17g liquid alum/100g litter. The litter pH was much lower (P&lt;0.05) for alum and liquid alum-treated litter than those of untreated litter. Moisture contents for all treatments at 0 and 2 weeks affect (P&lt;0.05), but there were no significantly differences among all treatments at 1 and 3 weeks. Application of alum and liquid alum with the different rates increased EC, ammonium, and decreased soluble reactive phosphorus (ranging from 30% to 85.4%) when compared to the controls. These results indicate that using one of the several techniques, acidification, litter amendments would be an alternative option for holding litter NH4 and reducing soluble reactive P by lowering litter pH

Effects of supplementing broiler diets with a combination of fermented red ginseng marc powder and red-koji on thigh meat quality of broiler chick during storage

ABSTRACT We assessed the effects of supplementing broiler diets with a combination of fermented red ginseng marc powder and red-koji on thigh meat quality of broiler chick during storage. Broilers (n = 120) were randomly assigned to one of two groups: control or treatment with 1% fermented red ginseng marc combined with red-koji. There were four replicates per group, each comprising 15 birds (10 male and 5 female). Neither the dietary supplementation group nor the number of storage days had a significant (p > 0.05) effect on meat pH. However, TBARS, a measure of lipid oxidation, was significantly affected (p < 0.05) by both the number of storage days and the dietary supplementation, with reduced TBARS activity noted in the treatment group after 7 days of storage. There was no significant impact (p > 0.05) on the lightness (L*) of meat in group after 1 and 7 day of storage (included T1 group), or redness (a*) of meat in group at 1 through 7 days of storage, whereas the yellowness (b*) of meat in both groups increased significantly (p < 0.05) with an increase in storage duration. Our results suggest that supplementing broiler diets with fermented red ginseng marc combined red-koji powder does not affect meat color, even after storage. We conclude that dietary supplementation with 1% fermented red ginseng powder combined with red-koji can reduce lipid oxidation in broiler thigh meat after 7 days of storage