Reaction pathways in the chlorination of amino acids

Chlorination is one of the most widely used disinfection technique in drinking water treatment. However, during chlorination, the chlorine can also reacted with organic matter in the water to produce potentially harmful and odorous by-products. This Thesis investigated the reaction and formation pathways of these potentially harmful and odorous by products from the reaction between chlorine and amino acids and therefore aid in the prevention of the formation of these by-products

Silicon Membrane Thickness Monitoring System based on Optical Sensing system

Silicon wafer etching is frequently used in micromachining and microelectronic fabrication processes. How to precisely control the thickness of etched silicon membrane is very challenging. Controlling the etching depth by controlling the etching time can result in large errors due to fluctuation of etching rate. A more accurate in-situ silicon membrane thickness monitoring system during silicon wafer etching is very necessary. In this poster, we proposed a silicon membrane thickness in-situ monitoring system based on optical sensing. A halogen lamp generates light to be passed through the silicon membrane. The light is partially absorbed while transmitting the silicon wafer depending on the thickness of the membrane. Two photodiodes are used to detect the lights passing through the silicon membrane at different wavelengths. The difference of the readings is used to cancel out the common errors, hence leading to improved accuracy. The system is designed and simulated to verify its optical responses. The experimental setup of the system is implemented and the results are analyzed. The proposed Silicon membrane thickness monitoring system can be used to monitor and control the etching depth to achieve precise silicon membrane thickness as needed

서울시 ‘따릉이’를 중심으로

학위논문(석사) -- 서울대학교대학원 : 공과대학 건설환경공학부, 2022.2. 황준석.더욱 합리적이고 인간적인 공공자전거 서비스를 제공하기 위해서 공공자전거가 시스템 더 효율적으로 운영되고 서비스 이용자 만족도를 높이도록 한 가지 자전거 재배치 경로 최적화 목적으로 공공자전거 재배치 최적화 모델을 제시하였다. 기존 재배치 모델들의 속도 느림, 정확도 낮음 등 한계점을 개선하기 위해서, 본 논문에서 GA와 ACO 알고리즘을 조합돼서 GAACO-BSP(a Genetic Hybrid Ant Colony Optimization Algorithm for Solving Bike-sharing Scheduling Problem) 알고리즘을 개발하였다. 그리고 성능 향상시키기 위하여 GA 수행횟수 제어 함수를 수립하여 두 알고리즘을 동적으로 연결하였다. 우선 GA가 스케줄링 가능한 초기해를 구하고, 그 다음으로 GA 수행횟수 제어 함수를 통해 최적 전환 시기를 파악해서 동적으로 ACO으로 전환한다. ACO가 GA에게서 초기화 필요한 페로몬을 얻고 최종 최적해를 찾는 것이다. 서울시 공공자전거 따릉이 사례로 결과를 검증하여, GAACO-BSP은 전통 단일 알고리즘보다 뛰어난 성능 우세로 대규모 자전거 시스템에 적용하고 더 짧은 시간 만에 재배치 거리를 더 많이 줄였다. 실험을 통해 GAACO-BSP가 실제 도시 공공자전거 시스템에서 적용할 수 있다는 것을 알 수 있다.To improve the service efficiency and customer satisfaction degree of public bicycle, a bike-sharing scheduling model is proposed, which aims to get the shortest length of the bicycle scheduling. To address the slow solution speed of the existing algorithms, which is not conducive to real-time scheduling optimization, this paper designed a Genetic Hybrid Ant Colony System Algorithm for Solving Bike-sharing Scheduling Problem (GAACS-BSP). Genetic algorithm was used to search initial feasible scheme， which was used to initialize pheromone distribution of ant colony algorithm. It solved problem of lack initial pheromone, to improve the efficiency of bike-sharing scheduling tasks. There also proposed a genetic algorithm control function to control the appropriate combination opportunity of the two algorithms. Finally, the results show that compared with GA or ACS, it is more suitable for solving the problem of large-scale bike-sharing scheduling tasks, which shortens the scheduling distance in a short period.제 1 장 서 론 1 1.1. 연구의 배경 1 1.2. 연구의 내용 2 제 2 장 선행 연구 3 2.1. 기존 공공자전거 재배치에 관한 연구 3 2.2. 기존 GA-ACO 융합 알고리즘 5 제 3 장 모델 구축 방법론 8 3.1. BSP 문제의 수학적 해석 8 3.2. BSP 해결을 위한 GAACO-BSP 11 3.2.1. 기본 생각 11 3.2.2. 전체 프레임워크 11 제 4 장 GAACO-BSP 알고리즘 13 4.1. GA 부분의 규칙 14 4.1.1. 인코딩 방식 및 초기화 14 4.1.2. 선택 15 4.1.3. 교차 및 변이 15 4.1.4. 정지 조건 및 전환 16 4.2. ACO 부분의 규칙 17 4.2.1. ACO 초기화 17 4.2.2. 경로 선택 규칙 18 4.2.3. Pheromone 농도 조절 18 4.3. 알고리즘 흐름도 20 제 5 장 실험 및 결과 21 5.1. 데이터 전처리 21 5.2. 지역센터(배송팀) 재구분 26 5.3. 재배치 전략방안 도출 29 5.3.1. 수요현황 분석 29 5.3.2. 재배치 최적화 방안 도출 32 제 6 장 결 론 38 참고 문헌 41석

4,4′-Bis(benzimidazol-1-yl)biphen­yl

The mol­ecule of the title compound, C26H18N4, resides on a crystallographic inversion centre with a dihedral angle of 44.94 (5)° between the benzimidazole ring system and the benzene ring. The primary hydrogen bond is C—H⋯N and inversion-related pairs of these generate a chain of rings along the c-axis direction; π⋯π stacking involving the benzimidazole groups with inter­planar separations of ca 3.4 Å complete the inter­actions

Incorporating Probing Signals into Multimodal Machine Translation via Visual Question-Answering Pairs

This paper presents an in-depth study of multimodal machine translation (MMT), examining the prevailing understanding that MMT systems exhibit decreased sensitivity to visual information when text inputs are complete. Instead, we attribute this phenomenon to insufficient cross-modal interaction, rather than image information redundancy. A novel approach is proposed to generate parallel Visual Question-Answering (VQA) style pairs from the source text, fostering more robust cross-modal interaction. Using Large Language Models (LLMs), we explicitly model the probing signal in MMT to convert it into VQA-style data to create the Multi30K-VQA dataset. An MMT-VQA multitask learning framework is introduced to incorporate explicit probing signals from the dataset into the MMT training process. Experimental results on two widely-used benchmarks demonstrate the effectiveness of this novel approach. Our code and data would be available at: \url{https://github.com/libeineu/MMT-VQA}.Comment: Findings of EMNLP202

Chlorination of Amino Acids: Reaction Pathways and Reaction Rates

Chlorination of amino acids can result in the formation of organic monochloramines or organic dichloramines, depending on the chlorine to amino acid ratio (Cl:AA). After formation, organic chloramines degrade into aldehydes, nitriles and N-chloraldimines. In this paper, the formation of organic chloramines from chlorination of lysine, tyrosine and valine were investigated. Chlorination of tyrosine and lysine demonstrated that the presence of a reactive secondary group can increase the Cl:AA ratio required for the formation of N,N-dichloramines, and potentially alter the reaction pathways between chlorine and amino acids, resulting in the formation of unexpected by-products. In a detailed investigation, we report rate constants for all reactions in the chlorination of valine, for the first time, using experimental results and modelling. At Cl:AA = 2.8, the chlorine was found to first react quickly with valine (5.4x104 M-1 s-1) to form N-monochlorovaline, with a slower subsequent reaction with N-monochlorovaline to form N,N-dichlorovaline (4.9x102 M-1 s-1), although some N-monochlorovaline degraded into isobutyraldehyde (1.0x10-4 s-1). The N,N-dichlorovaline then competitively degraded into isobutyronitrile (1.3x10-4 s-1) and N-chloroisobutyraldimine (1.2x10-4 s-1). In conventional drinking water disinfection, N-chloroisobutyraldimine can potentially be formed in concentrations higher than its odour threshold concentration, resulting in aesthetic challenges and an unknown health risk

Fabrication of Concussion Resistant Nanocomposites

Studying concussions is of paramount importance. Concussions occurring in sports and sudden other accidental cases are causing major injuries to people often times it leads to CTE and eventual death. Chronic Traumatic Encephalopathy (CTE) is one type of degenerative brain disease that can be found in athletes, military veterans, and other people who have repetitive brain trauma. CTE is usually caused by repetitive hits to the head sustained over a period of years, most people diagnosed with CTE suffered hundreds or thousands of head impacts over the course of many years, such as playing contact sports or serving in the military. PDMS-based nanomaterials are gaining widespread attention in this regard. We report the use PDMS polymer and graphene oxide/graphene as nanoparticle reinforcement to produce the vibration-absorbing PDMS-graphene nanocomposite. The stiffness of PDMS and graphene-PDMS nanocomposites were measured using dynamic mechanical analyzer. We prepared a well-controlled pore containing PDMS-graphene nanocomposites that exhibited significant improvement in impact absorption properties as a function of porosity. Visual Molecular Dynamics (VMD) was used to compute the physical interactions between graphene and PDMS

The inapplicability of objectivity: understanding the work of data journalism

Data journalism is an emerging form of journalism, entailing the discovery of stories in data with the assistance of data algorithms. The burgeoning literature has largely interpreted the work of data journalism through the lens of objectivity. This paper, however, rejects the applicability of objectivity to data journalism. This inapplicability is the product of five factors: the extensive use of data and data algorithms in journalism; the difficulty in verifying data; the imbalance in data and data access; the uncertainty about if and to what extent data journalists can obtain sufficient knowledge of data contexts and algorithms; and their “design subjectivity” in the data processing process. Data reporting becomes a process of knowledge construction under the influence of these factors. The article argues that because of the social constructionist nature of data journalism, serving the public interest and democracy is a more appropriate principle than objectivity for data journalism. It suggests shifting academic attention from celebrating objectivity in data journalism to examining the epistemology of data journalists, the factors influencing data journalists’ formation of knowledge in reporting, their defence of cultural authority, and the democratic meanings of data reports in future research. Such understanding also has implications for data journalism pedagogy and practice

Association between monocyte lymphocyte ratio and abdominal aortic calcification in US adults: A cross-sectional study

Background This study aimed to evaluate the association between Monocyte Lymphocyte Ratio (MLR) and Abdominal Aortic Calcification (AAC) in adults over 40 years of age in the United States. Methods Data were collected from the 2013–2014 National Health and Nutrition Examination Survey (NHANES). AAC was quantified by the Kauppila score system based on dual-energy X-Ray absorptiometry. Severe AAC was defined as a total AAC score > 6. The lymphocyte count and monocyte count can be directly obtained from laboratory data files. Multivariable logistic regression models were used to determine the association between MLR and the AAC score and severe AAC. Results A total of 3,045 participants were included in the present study. After adjusting for multiple covariates, MLR was positively associated with higher AAC score (β = 0.21, 95% CI 0.07, 0.34, p = 0.0032) and the odds of severe AAC increased by 14% per 0.1 unit increase in the MLR (OR = 1.14, 95% CI 1.00, 1.31, p = 0.0541). The Odds Ratio (OR) (95% CI) of severe AAC for participants in MLR tertile 3 was 1.88 (1.02, 3.47) compared with those in tertile 1 (p for trend = 0.0341). Subgroup analyses showed that a stronger association was detected in the elderly compared with non-elderly (p for interaction = 0.0346) and diabetes compared with non-diabetes (borderline significant p for interaction = 0.0578). Conclusion In adults in the United States, MLR was associated with higher AAC scores and a higher probability of severe AAC. MLR may become a promising tool to predict the risk of AAC

Study on spatial form types of industrial remains in high-density cities : a case study of Suzhou Creek area in Shanghai

Industrial remains in high-density cities are not only important physical carriers of urban development but also historical space with the particularity of spatial form. It is helpful to promote the sustainable transformation of the industrial district by analyzing its spatial form and establishing adaptive renovation measures. This paper focuses on the surrounding area of Suzhou Creek in Shanghai, the main industrial cluster in Shanghai's central city, and takes 129 industrial remains on both sides as samples. Based on the method of urban morphology of Conzenian School and the characteristics of industrial remains in Shanghai, this paper establishes a research framework of spatial morphology from three dimensions of "Unit plan"," Building type" and " Building function", and summarizes four form types of industrial remains: Dense organization, Clustered organization, Scattered organization, and Single-building organization. Analyzing their characteristics and discussing their formation mechanism to provide more possibilities for sustainable development in the future