Safety Criteria Research Articles

Feasibility, safety, and adherence of a remote physical and cognitive exercise protocol for older women.

Population aging and the consequences of social distancing after the COVID-19 pandemic make it relevant to investigate the feasibility of remote interventions and their potential effects on averting functional decline. (1) To investigate the feasibility, safety, and adherence of a remote protocol involving physical and cognitive exercises for older women with normal cognition; (2) to examine its effects on cognitive and well-being variables. Twenty-nine women (age ≥ 60 years old) were randomized into experimental group (EG; n = 15) and control group (CG; n = 14). The EG performed a 40-minute session of cognitive and physical exercises, and CG performed a 20-minute stretching session. Both groups performed 20 sessions via videoconference and 20 on YouTube twice a week. The Mini-Mental State Examination, Verbal Fluency Test, Digit Span (direct an inverse order), Geriatric Depression Scale (GDS), and Well-being Index (WHO-5) were applied in pre- and post-interventions by phone. Overall adherence was 82.25% in EG and 74.29% in CG. The occurrence of adverse events (mild muscle pain) was 33.3% in EG and 21.4% in CG. The EG improved verbal fluency and attention (p ≤ 0.05); both groups had improved depressive symptoms. The present study met the pre-established criteria for feasibility, safety, and adherence to the remote exercise protocol among older women. The results suggest that a combined protocol has more significant potential to improve cognitive function. Both interventions were beneficial in improving the subjective perception of well-being.

Moving from ethnic exclusions to cultural safety: how is athlete ethnicity discussed in research on menstrual health in sports? A scoping review

ObjectiveThis study aims to investigate how athlete ethnicity is discussed in the inclusion and exclusion criteria, methodology, findings, and conclusions of research focused on menstrual health in sports science and...

Assessing thermal hazards in bio-oil-glyoxal polymerization and curing with DGEBA and bio-char

Traditional novolac resin uses formaldehyde and an excess of phenol under an acid catalyst which has a remarkable production and wide applications, however, the polymerization and its curing reaction are highly exothermic and heat generation with the release of harmful gases (formaldehyde and phenol) link to a high potential of thermal runaway hazard and the possibility of explosions in resin factories. To make a sustainable novolac-type resin, the water-insoluble fraction of bio-oil glyoxal (BOG) resin was utilized as an ideal phenol bioresource. The safety criteria of renewable resins polymerization and its curing reaction were investigated using the Differential Scanning Calorimeter (DSC) and evaluated by comparing the critical runaway conditions with those of traditional non-renewable resins. The reaction mechanism of the novolac resin synthesis and curing reaction were discussed as well. The results indicate that the use of bio-oil can reduce the heat risk of polymerization reactions. The introduction of biochar for the first time in curing reactions has shown a potential beyond anticipation in reducing the heat risk of curing reactions.

Assessing the performance of a radioactive waste repository over geological timescales: past experience and the way forward

The successful implementation of plans to develop a repository for radioactive waste in the United Kingdom will require an assessment of the ability of the facility to meet appropriate regulatory safety criteria at all stages during its construction, operation and after closure. As part of this assessment, an environmental safety case (ESC) will be presented and this will contain a collection of claims, arguments and evidence which collectively demonstrate that long-term safety can be achieved and maintained. Natural analogues (NA) can be helpful in demonstrating understanding of aspects of repository performance by, for example, providing evidence that certain materials can survive for long periods. Appropriate NAs can be critical to providing long-term practical demonstrations to support the theoretical and mathematical arguments of the ESC and they may have a significant role in the overall process understanding. As part of the ongoing repository development programme in the UK, an updated version of an existing catalogue of NA studies (focussed on the requirements of the ESC) has been produced and the background to NA studies in general, and to the catalogue in particular, are presented here. Thematic collection: This article is part of the Sustainable geological disposal and containment of radioactive waste collection available at: https://www.lyellcollection.org/topic/collections/radioactive

Statistical estimation of noise induced hearing loss among the drivers in one of the most polluted cities of India

In the present study, an attempt has been made to assess the impact of vehicular noise upon the 3-wheeler tempo drivers and to know whether there is any relationship between hearing loss and cumulative noise exposure. For this purpose, 3-wheeler tempo drivers (Exposed group) and non-commercial light motor vehicle car drivers (Unexposed group) were chosen as study subjects. Three traffic routes were selected to assess the noise level during waiting and running time in the exposed and unexposed groups. Among all three routes, the highest mean noise level (Leq) was observed on the Chowk to Dubagga route for waiting and en-route noise measurement. It was measured as 84.13 dB(A) and 86.36 dB(A) for waiting and en-route periods of 7.68 ± 3.46 and 31.05 ± 6.6 min, respectively. Cumulative noise exposure was found to be significantly different (p < 0.001) in all age groups of exposed and unexposed drivers. Audiometric tests have been performed over both exposed and unexposed groups. The regression analysis has been done keeping hearing loss among tempo drivers as the dependent variable and age (years) and Energy (Pa2 Hrs) as the independent variable using three different criteria of hearing loss definitions, i.e., World Health Organization, National Institute for Occupational Safety and Health (NIOSH), Occupational Safety and Health Administration criteria. Among these three criteria, the NIOSH criterion of hearing loss best explained the independent variables. It could explain the total variation in dependent variable by independent variable quite well, i.e., 68.1%. The finding showed a linear relationship between cumulative noise exposures (Pa2 Hrs) and the exposed group's hearing loss (dB), i.e., hearing loss increases with increasing noise dose. Based on the findings, two model equations were developed to identify the safe and unsafe noise levels with exposure time.

Improvement of Curvature Change Rate (Parameter) in Two-Line Rural Roads

The studies in various countries show that one of the main causes of accidents on rural roads still remains the drivers’ errors in choosing safe speed, which can be attributed to the errors of perceiving the road alignment. The current practice shows that the engineering safety improvement measures as well as accident prevention measures such as intersection design, traffic signs and equipment, facilities for vulnerable road users, access management, and human behaviour are not always effective. Probably, one of the alternatives to solve this problem is a design methodology that is used in the European Union countries and based on road safety criteria and road safety module. This methodology is aimed at ensuring design consistency between the elements of road alignment in a way that the driver intuitively chooses safe speed or the probability of errors in perceiving the road alignment is minimum. The article presents experimental research carried out in Vilnius Gediminas Technical University, the objective of which is to determine the accuracy of road safety module and to suggest possible alternatives for its improvement.

Microbiological analysis of broiler chicken slaughter products using “Subtiform” probiotic and establishment of safety and technological process criteria

Feeding broiler chickens a probiotic biopreparation containing bacteria of the genus Bacillus subtilis and Bacillus licheniformis leads to improved feed digestion, increased productivity, and immune status, as well as reduced insemination by opportunistic and pathogenic microorganisms of slaughter products. It enhances the level of prevention and treatment of various poultry diseases. The purpose of the work is to carry out a microbiological analysis of the slaughter products of broiler chickens after drinking the probiotic biological preparation “Subtiform” in doses of 0.5 g, 2.0, and 4.0 g per 10 dm3 of water. The material (major pectoral muscle and internal organs) was examined by bacteriological methods. It was established that the content of MAFAM in the control and experimental groups 1, 2, and 3 of the chilled slaughter products of broiler chickens for 1, 3, and 5 days of storage at a temperature of 0–4 °С was within the limits of standards (no more than 1.0×104 CFU/d). It was established that when broiler chickens were given 4.0 g/10 dm3 of water, the MAFAM content for one day of poultry meat storage decreased by 10.4 % (Р &lt; 0.05); on the third day of storage, it decreased by 9.6 % (Р &lt; 0.05); at the beginning of the fifth day of storage, the decrease was, respectively, by 11.3 % (Р &lt; 0.01) compared to the indicators of the control group. The content of MAFAM in offal, in particular in the heart of broiler chickens, was reduced in experimental group 3 by 36.9 % (Р &lt; 0.001); in the liver – by 33.6% (Р &lt; 0.001); in the muscular part of the stomach – by 27.2 % (Р &lt; 0.001); in the spleen and lungs, there was also a decrease in the content of MAFAM in experimental group 3, respectively, by 20.2 % (Р &lt; 0.01) and 23.6 % (Р &lt; 0.01) compared to the indicators of the control group of broiler chickens. It was established that opportunistic pathogenic microorganisms, in particular BGCP, bacteria of the genus Proteus, and pathogenic microorganisms, in specific bacteria of the genus Salmonella, bacteria of the species Staphylococcus aureus, Listeria monocytogenes in 25 grams of the large pectoral muscle of broiler chickens and internal organs (heart, spleen, liver, the muscular part of the stomach and lungs) were not detected. According to the results of the conducted research, an adverse effect of the probiotic biopreparation at a dose of 4.0 g/10 dm3 of water on the development of microorganisms in the large pectoral muscle and internal organs of broiler chickens was established. Therefore, the probiotic “Subtiform” at a dose of 4.0 g/10 dm3 of water during the drinking of broiler chickens can be recommended to increase productivity and obtain safe slaughter products. The practical value of the work consisted of establishing the microbiological indicators of poultry slaughter products after drinking probiotics, as well as establishing safety criteria and the technological process.

Does deep TMS really works for smoking cessation? A prospective, double blind, randomized, sham controlled study

Introduction: A substantial proportion of smokers wishing to quit do not stop smoking when using current therapies to aid cessation. Magnetic pulses to specific brain areas designated as transcranial magnetic stimulation may modulate brain activity and thereby change chemical dependencies. Deep transcranial magnetic stimulation (dTMS) with the H4 coil stimulates neuronal pathways in the lateral prefrontal cortex and insula bilaterally, areas involved in tobacco addiction. Objective: To evaluate the efficacy and safety of dTMS with T4 coil in smoking cessation. Methods: In a double blind, controlled clinical trial, adult smokers of at least 10 cigarettes/day were randomized to active (n = 50) versus sham dTMS (n = 50). The protocol involved up to 21 sessions administered over up to 12 weeks. Tobacco use was monitored by self-report and confirmed by expired air monoximetry (at each dTMS visit) and blood cotinine (at the screening visit and at the end of sessions). Participants completed abstinence, mood and cognition scales at determined timepoints during follow-up. Results: In the intention to-treat-analysis, the cessation rate of the intervention and control groups was 14.0%. The reported side effects were as expected for this procedure. Although there were no serious adverse events, three participants were withdrawn according to safety criteria. Conclusion: Active treatment with dTMS H4 coil was safe but not effective for smoking cessation.

Assessment of physician compliance to the CAEP 2021 Atrial Fibrillation Best Practices Checklist for rate and rhythm control in the emergency department.

Acute atrial fibrillation and flutter (AF/AFL) are common arrhythmias treated in the emergency department (ED). The 2021 CAEP Best Practices Checklist provides clear recommendations for management of patients with acute AF/AFL. This study aimed to evaluate physician compliance to Checklist recommendations for risk assessment and ED management of AF/AFL. This health records review assessed the management of adult patients presenting to two tertiary care EDs for management of acute AF/AFL from January to August, 2022. All ECGs demonstrating AF/AFL with a heart rate greater than 100 were compiled to capture primary and secondary causes. All visits were assessed for rate and rhythm control management, adverse events, return to ED, and safety criteria. Study physicians classified safety criteria from the Checklist into high and moderate concerns. The primary outcome was the proportion of cases with safety concerns and adverse events occurring during management in the ED. Data were analyzed using simple descriptive statistics. We included 429 patients with a mean age of 67.7years and 57.1% male. ED management included rate control (20.4%), electrical (40.1%), and pharmacological (20.1%) cardioversion. Adverse events occurred in 9.5% of cases: 12.5% in rate control, 13.4% in electrical cardioversion, and 6.9% in pharmacologic cardioversion. Overall, 7.9% of cases had management safety concerns. Moderate safety concerns occurred in 4.9% of cases including failure to attain recommended heart rate at time of discharge (3.9%). Severe concerns were identified in 3.0% of cases including failure to cardiovert unstable patients (1.2%). The 30-day return-to-ED rate was 16.5% secondary to AF/AFL. ED management of AF/AFL was consistent with the CAEP Checklist and was safe overall. Opportunities for optimizing care include attaining recommended targets during rate control, avoidance of calcium channel and beta blockers in patients with systolic dysfunction, and earlier cardioversion for clinically unstable patients.

Профилактика роговичных осложнений послеоперационного адъювантного применения антиметаболитов после непроникающей глубокой склерэктомии

Original article Prevention of corneal complications after post-operative application of antimetabolites following nonpenetrating deep sclerectomy S.N. Svetozarskii, A.N. Andreev, A.V. Shvaikin, S.V. Scherbakova, I.G. Smetankin Volga District Medical Center under the Federal Medical and Biological Agency, Nizhny Novgorod, Russian Federation Privolzhsky Research Medical University under the Ministr y of Health of Russia, Nizhny Novgorod, Russian Federation Purpose. To evaluate the clinical and functional effectiveness of the developed method for prevention of corneal complications of nonpenetrating deep sclerectomy (NPDS) with postoperative adjuvant use of 5-fluorouracil in comparison with the control group. Material and methods. Retrospective comparative study in 2 groups included patients with open angle glaucoma who were initially underwent NPDS and received at least 1 subconjunctival injection of 5-fluorouracil in the postoperative period. 1st group included 101 patients (101 eyes) who underwent subconjunctival injection of 5-fluorouracil after surgery using standard technique, 2nd group included 176 patients (176 eyes) who underwent subconjunctival injection of 5-fluorouracil with prophylaxis of corneal complications. Best corrected visual acuity (BCVA), intraocular pressure (IOP), frequency of corneal complications and number of visits to the doctor during the first 4 weeks after surgery were analyzed as criteria of efficacy and safety. Results. Comparison groups did not differ in demographic characteristics and preoperative BCVA and IOP parameters. Fluorescein stained corneal epithelium defects were statistically significantly more frequently observed in 1st group (38.6%) in comparison with 2nd group (7.4%) (p&lt;0.001). Four weeks after NPDS, IOP decrease was 25.5% in 1st group and 31.5% in 2nd group (p=0.042). Mean BCVA loss was 1.9 lines in 1st group and 1.3 lines in 2nd group (p&lt;0.001). The number of follow-up visits during the first month after surgery was 0.6 less in 2nd group than in 1st group (p=0.002). Conclusion. Prevention of corneal complications simply and effectively reduces the risk of corneal epithelial defects after subconjunctival injection of 5-fluorouracil as well as markedly improves the clinical and functional results of NPDS and reduces the need for outpatient visits. Key words: antimetabolites, open-angle glaucoma, corneal erosion, toxicity, prevention of complications

Stability analysis of civil air defense tunnel under blasting vibration

Based on a large section drilling and blasting excavation project, the dynamic response characteristics of civil air defense tunnels are analyzed by combining field monitoring and numerical simulation. The dynamic response features include particle vibration velocity, main frequency, displacement, and stress, and the stability criterion of the tunnel is analyzed. A safety criterion model based on the ultimate tensile strength of materials is established. The results show that the frequency of the X, Y, and Z directions is mainly distributed in 90-140 Hz. The effective stress increases first and then decreases along the axis of the roadway. The stress near the explosion source is large and the relative reduction is also large. By fitting the relationship between blasting vibration velocity and maximum principal stress, the safe vibration velocity criterion based on tensile strength is obtained, and the safe threshold of vibration velocity is 19.62 cm/s. It can be assumed that blasting does not affect the structure.

Monitoring of bivalve mollusk harvesting areas: the relevance of Salmonella spp.

The microbiological monitoring of bivalve mollusk harvesting areas in the Marche region is based on the parameters of Escherichia coli and Salmonella spp. However, Regulation EU/2019/627 stated criteria based on E. coli only to determine the health status of these areas. Therefore, the reason for Salmonella spp. monitoring, as provided in the Marche region, could be aimed at reducing the risk of placing on the market contaminated bivalve mollusks. This study, using the results of microbiological monitoring carried out in the Marche region from 2015 to 2022 and the methods based on Bayes' theorem and Poisson's distribution, evaluated the effectiveness and efficiency of Salmonella spp. monitoring in reducing the risk to the consumer. The results show that i) the use of a single sample unit significantly reduced the possibility of detecting non-compliance with the microbiological safety criterion; ii) the time taken to report positive results (average of approximately 10 days) did not allow the timely implementation of control measures; iii) the prevalence of positive outcomes was quite sporadic: a random trend of positivity is recognizable on a geographical and monthly basis for mussels and a geographical basis for striped clams; iv) considering the predictive value of E. coli against Salmonella spp., the specificity is very high and the negative predictive value versus Salmonella spp. would be >80%. In conclusion, the study shows that the monitoring of Salmonella spp. has a limited effect on reducing the risk to the consumer; however, in the cost/benefit assessment, other aspects not covered by this study should be considered.

Terahertz Radiation Modulates Neuronal Morphology and Dynamics Properties.

Terahertz radiation falls within the spectrum of hydrogen bonding, molecular rotation, and vibration, as well as van der Waals forces, indicating that many biological macromolecules exhibit a strong absorption and resonance in this frequency band. Research has shown that the terahertz radiation of specific frequencies and energies can mediate changes in cellular morphology and function by exciting nonlinear resonance effects in proteins. However, current studies have mainly focused on the cellular level and lack systematic studies on multiple levels. Moreover, the mechanism and law of interaction between terahertz radiation and neurons are still unclear. Therefore, this paper analyzes the mechanisms by which terahertz radiation modulates the nervous system, and it analyzes and discusses the methods by which terahertz radiation modulates neurons. In addition, this paper reviews the laws of terahertz radiation's influence on neuronal morphology and kinetic properties and discusses them in detail in terms of terahertz radiation frequency, energy, and time. In the future, the safety of the terahertz radiation system should be considered first to construct the safety criterion of terahertz modulation, and the spatial resolution of the terahertz radiation system should be improved. In addition, the systematic improvement of the laws and mechanisms of terahertz modulation of the nervous system on multiple levels is the key to applying terahertz waves to neuroscience. This paper can provide a platform for researchers to understand the mechanism of the terahertz-nervous system interaction, its current status, and future research directions.

The Importance of Government Collaboration Strategies for Developing Tourism Villages in Indonesia

Purpose: The purpose of this research is to find out the existence of tourist villages that have not experienced development like other tourist village destinations that have experienced a lot of progress. Theoretical reference: Development of integrated tourist village destinations needs to be carried out through collaboration, with strong regional policies through cooperative strategies with various parties. Then the importance of collaboration is applied because according to Thomson from Wood and Gray (1991, 218): Collaboration means autonomous parties interacting through negotiations both formally and informally. Method: The type of research used in this research is a research method with a qualitative approach involving philosophical assumptions, applying a qualitative approach by collecting and analyzing various types of data, also involving collective functions so that the power of studying collectively is greater. and deeper (Creswell, 2013 :5) Results and Conclusions: The government needs to provide facilities and infrastructure that can support the achievement of safe, comfortable and healthy tourist village destinations. The development of eight tourism elements in tourist villages is quite varied and has not been packaged well. Kahayya Village has not developed like other tourist villages, because so far only the government has contributed to its development, access to land transportation is also limited, namely winding roads up hills that are not suitable for two-wheeled and four-wheeled vehicles. Collaboration with various parties is needed so that the potential of this tourist village can be recognized, developed and attracted by visitors. The requirements to become a tourist village worth visiting are like three villages that have eight tourism elements that could be a model. To develop a tourist village into a leading destination requires a fairly large budget. Research implications: The government needs to continue to provide professional guidance and management to increase the number of visits to tourist villages, by improving eight elements starting from: attractions, accessibility, amenities, accommodation, additional services (supporting facilities), supporting policies, and the government facilitating implementation regional regulations in strategic planning priorities and multi-party collaboration. Originality/Value: The tourist village destinations, namely Kahayya, Darubiah, Bontobahari, and Tanatoa all have potential with various types of interesting tourism ranging from the natural beauty of mountains, beaches, waterfall bathing, Pinishi Boat making rituals, and preserving traditional Ammatoa culture. Villages that have not yet experienced development require strong collaboration between various parties ranging from government officials, business actors, academics, society, media, to tourists so that they can work together to support the implementation of tourist villages that are worth visiting and meet the safety and comfort criteria of tourists.

Novel Probiotic Candidates in Artisanal Feta-Type Kefalonian Cheese: Unveiling a Still-Undisclosed Biodiversity.

Autochthonous dairy lactic acid bacteria (LAB) isolates encompass a natural source of starter, adjunct, or probiotic candidates. In this context, traditionally manufactured, using exclusively animal rennet, Feta-type cheeses were collected from five farms located in different regions of Kefalonia island (Greece). The primary objective of this study was to isolate and characterize novel LAB, thereby exploring the unmapped microbial communities of Kefalonian Feta-type cheese and identifying new potential probiotics. The initial screening, included a preliminary gastrointestinal (GI) tolerance assessment (acidic conditions and bile salts), followed by their safety evaluation (hemolytic activity and antibiotic susceptibility). Based on the preliminary screening, selected strains underwent molecular identification and were further investigated for their probiotic attributes (lysozyme and phenol resistance, antimicrobial traits, antidiabetic aspects, cholesterol reduction and adhesion, adhesion to Caco-2 cells, and milk acidification potential). The results showed that 49, out of the 93 retrieved isolates, exhibited resistance to GI conditions, whereas 18 met the safety criteria. The molecular identification revealed strains belonging to the species Lactiplantibacillus plantarum, Limosilactobacillus fermentum, Lacticaseibacillus rhamnosus, and Lacticaseibacillus paracasei. The selected rod-shaped 14 isolates displayed a potential probiotic character. The best-performing isolates concerning cholesterol assimilation and adhesion, α-glucosidase inhibition, and epithelial adherence were Lpb. plantarum F89, F162, and F254 and Lcb. paracasei F214 and F216, whereas Lcb. paracasei F70 showed potential as a defined strain starter. The present study explores for the first time the biodiversity of traditionally fermented microbial communities in Kefalonian Feta-type cheese, revealing novel potential probiotic strains that can contribute to the development of innovative functional food products.

Viability of probiotic lactic acid bacteria in Malay apple (Syzygium malaccense) during fermentation and storage

For lactic acid bacteria (LAB) to be considered probiotic it must colonize and survive the gut environment, also for maximum health benefits it must be ingested in a sufficient amount. Hence, this study was aimed at investigating the probiotic potential of lactic acid bacteria and their viability in Malay apple juice. Five LAB of yoghurt origin were obtained and screened for probiotic potential using acidic pH (1.5) tolerance, bile salt (0.3 %) resistance and non-hemolytic activity as the selection and safety criteria. The compositional and physicochemical characteristics of the apple juice during fermentation were assayed using standard methods. The viable cell counts were determined using standard plate count method. Of the 5 LAB isolates 2 identified as members of Lactobacillus and Lactococcus genera showed good probiotic characteristics with acidic pH and bile salt survival rate of above 80 %, also the 2 LAB isolates were non-hemolytic. After the 72 h fermentation increase in protein content ranged from 0.53 to 1.21 %, titratable acidity increase ranged from 0.35 to 0.53 % and a reduction in pH ranged from 4.54 to 3.58 were obtained, also the viable cell counts were at 4.12±0.38, 2.35±0.15 and 3.18±0.10 CFU/ml in the Lactobacillus, Lactococcus and mixed culture fermented juice respectively. At the end of the 30 days cold (4oC) storage the viable cell counts were &gt;106 CFU/ml. The Lactobacillus fermented juice had more overall acceptability (7.7) by the panelists. In conclusion the studied LAB isolates were viable probiotics and Malay apple juice a suitable carrier for probiotics.

SUITABLE LANDING SITE SELECTION FOR UNMANNED AERIAL VEHICLES USING AIRBORNE LASER SCANNING POINT CLOUD

Abstract. In the context of autonomous landing for unmanned aerial vehicles (UAVs), selecting a suitable landing site is crucial. This research presents a new method for automatically identifying safe landing sites based on point cloud data acquired through an airborne laser scanning (ALS) system. The proposed approach begins by detecting flat regions using principal component analysis (PCA) and region-growing algorithms. Subsequently, a terrain complexity assessment is conducted through plane fitting using an enhanced progressive sample consensus (PROSAC) algorithm. This assessment assists in identifying the most suitable landing site within a specified landing zone. The method's effectiveness is demonstrated through experiments conducted on two distinct natural terrains from the DALE dataset. The results show that the proposed approach can accurately classify landing zones and identify preferred sites that meet safety criteria. This study's findings underscore the proposed method's effectiveness and feasibility in improving the safety and reliability of autonomous UAV landings.

A novel approach for designing efficient and sustainable cooling cycles with low global warming potential refrigerants

With the current legislation on the phase-out of 3rd generation refrigerants, new cooling cycles are expected to operate with 4th generation refrigerants, hence, the need for optimal system performance with these new working fluids. In this study, an innovative optimization approach was applied for the design of cooling cycles with 4th generation refrigerants based on integrating statistical analysis design of experiments (DoE) with molecular modeling using the polar soft-SAFT model. First, a detailed multi-criteria assessment was applied for the selection of 4th generation refrigerants in medium–low temperature applications. Results demonstrated the potentiality of trans-1,3,3,3-tetrafluoroprop-1-ene (R1234ze(E)) or cis-1,2,3,3,3-pentafluoroprop-1-ene (R1225ye(Z)) in terms of environmental, safety, and technical criteria in basic cooling cycles under specific operating conditions. Multi-objective optimization guided using statistical analysis tools were implemented to study potential enhancement in cooling cycle performance using these promising refrigerants in terms of energy and exergy efficiency. This included evaporator and condenser temperature, fluid choice, compression yield, superheating/subcooling degrees, and cycle type. The evaporation and condenser temperature, and the compressor efficiency are shown to monopolize more than three-quarters of the cumulative contribution on system efficiency for those operated with R1234ze(E) in advanced liquid-to-suction line heat exchangers (LL/SL-IHX). Further optimization through examining the effect of heat transfer phenomena assisted in determining optimal operating conditions for new systems operating with low GWP refrigerants, instilling annual cost savings of $1.59 K and reduction in CO2 emissions by 1.02 tCO2-eq compared to the baseline system.

A Quantitative Risk Analysis during Truck-to-Ship Ammonia Bunkering

A primary objective for the sustainable development of the maritime sector is to transition toward carbon-neutral fuels, with the aim to reduce emissions from maritime transportation. Ammonia emerges as a promising contender for hydrogen storage, offering the potential for CO2-free energy systems in the future. Notably, ammonia presents advantageous attributes for hydrogen storage, such as its high volumetric hydrogen density, low storage pressure requirements, and long-term stability. However, it is important to acknowledge that ammonia also poses challenges due to its toxicity, flammability, and corrosive nature, presenting more serious safety concerns that need to be addressed compared with other alternative fuels. This study sought to explore the dispersion characteristics of leaked gas during truck-to-ship ammonia bunkering, providing insights into the establishment of appropriate safety zones to minimize the potential hazards associated with this process. The research encompassed parametric studies conducted under various operational and environmental conditions, including different bunkering conditions, gas leak rates, wind speeds, and ammonia toxic doses. EFFECTS, which is commercial software for consequence analysis, was utilized to analyze specific scenarios. The focus was on a hypothetical ammonia bunkering truck of 37,000 L refueling an 8973 deadweight tonnage (DWT) service vessel with a tank capacity of 7500 m3 in the area of Mokpo Port, South Korea. The study’s findings underscore that the ammonia leak rate, ambient temperature, and wind characteristics significantly impacted the determination of safety zones. Additionally, the bunkering conditions, leak hole size, and surrounding traffic also played influential roles. This study revealed that bunkering in winter resulted in a larger safety zone compared with bunkering in summer. The lethality dose of ammonia was affected by the leak hole size, time for dispersion, and the amount of ammonia released. These observed variations imply that ammonia truck-to-ship bunkering should be undertaken with carefully chosen suitable safety criteria, thereby significantly altering the scope of safety zones. Consequently, the risk assessment method outlined in this paper is expected to assist in determining the appropriate extent of safety zones and provide practical insights for port authorities and flag states contributing to the future sustainable development of the maritime industry.

A Study on Safety Criteria for Toppling of Pile Drivers and Cranes Based on Structural Stability

The toppling mechanisms of heavy machinery with high center of gravity such as pile drivers, cranes, jacks, etc., can be broadly classified into two categories: overturning moment toppling and structural instability toppling. The structural instability toppling is further divided into buckling toppling and equilibrium transition toppling. These three toppling mechanisms are significantly different, and it is necessary to address their safety separately when discussing safety criteria. Therefore, it is considered that safety criteria should be established coping with characteristics of each toppling mechanism. In particular, toppling in the case of structural instability has not had clear safety criteria so far, and the development of rational safety criteria based on structural stability theory is considered important to prevent future toppling accidents. This paper provides a sample of the safety criteria that align with the classification of the three toppling mechanisms. For the buckling toppling, the criterion is set to restrict the vertical load considering the critical load (buckling). For the overturning moment toppling, the criterion is set to restrict the inclination angle in order not to exceed the stability limit angle. Additionally, for the equilibrium transition toppling, the criterion is set on both the vertical load and the inclination angle so that the maximum displacement angle due to dynamic inertial force does not exceed the stability limit angle. A sample of the safety criteria provided in this paper includes the three toppling mechanisms which should be covered to avoid the toppling accidents of heavy machinery which has high center of gravity.