Transmission Chain Research Articles

Introduction and Spread of Dengue Virus 3, Florida, USA, May 2022-April 2023.

During May 2022-April 2023, dengue virus serotype 3 was identified among 601 travel-associated and 61 locally acquired dengue cases in Florida, USA. All 203 sequenced genomes belonged to the same genotype III lineage and revealed potential transmission chains in which most locally acquired cases occurred shortly after introduction, with little sustained transmission.

في سند الحديث النبوي عند بعض المستشرقين (Common Link) شبهة وضع الحديث عن طريق الراوي المركزي

This research delves into studying the suspicion of Hadith fabrication through the concept of the "central narrator" in the chain of narration according to some orientalists who attempt to cast doubt on the authenticity of Prophetic Hadiths from the Messenger of Allah, peace be upon him, through an analytical and critical approach. The objectives of this research are firstly: to understand the true essence of the theory of the central narrator as perceived by some orientalists before critiquing it. Secondly: to comprehend the methodology adopted by some orientalists in presenting this theory in the chains of Hadith narrations. Thirdly: to critique and invalidate this theory in an attempt to uphold the authenticity of Prophetic Hadiths as the secondary source for understanding religious rulings and teachings. The hypotheses of this research are: The first hypothesis suggests that the theory posits that most of the currently recorded Prophetic Hadiths, in terms of their chains of transmission, are centered around narrators in the layer after the major successors of the companions, whom these narrators are referred to as the central narrators or what is known in English as the "common link". Based on this premise, some orientalists believe that the majority of Prophetic Hadiths are fabricated by these central narrators. The second hypothesis suggests that the methodology adopted by some orientalists in presenting this theory involves analyzing the chain of transmission through the following steps: first, identifying the text of the Hadith intended for analysis; second, tracing the text of the Hadith in Hadith books; third, gathering the chains of transmission for that Hadith; and fourth, constructing that chain of transmission into a unified entity. The third hypothesis suggests that the theory of the common link or the central narrator in the chain of Hadith transmission is invalidated by the theory of evidence and corroborations in Prophetic Hadiths, which focus on the two fundamental components of Hadith: the chain of transmission and the text.

The importance of this study comes from the virtue and importance of the Sunnah of the Prophet, which is the second source of Islamic legislation, as knowledge of the condition of the men of the chain of transmission who lead to the narration of the Proph

The importance of this study comes from the virtue and importance of the Sunnah of the Prophet, which is the second source of Islamic legislation, as knowledge of the condition of the men of the chain of transmission who lead to the narration of the Prophet – may Allah bless him and grant him peace - is one of the most important aspects of preserving this religion. Therefore, we see that critics from the people of this matter paid attention to the chain of transmission thorough investigation into the conditions of the narrators, examining and modifying them. According to the critics, mixing is considered one of the important matters for preserving the Sunnah of the Prophet, and it is worth noting to determine the period during which the narrator whose narration was accepted was mixed, as it is one of the most difficult tasks of critics, because mixing begins gradually, which affects the acceptance of the narration before it becomes clear and appears to the public. Objective of the study: The study aims to identify the methods and approaches followed by hadith scholars in explaining the condition of the mixed narrator to avoid the transmitted narrators being deceived by the mixed narration, especially the preserved ones. The reason for choosing the topic: The topic is chosen in order to show that the effect of mixing on the response of the novel is important. Some of the narrations are rejected and some are accepted, and this is what will become clear through my research. Research method and plan: I followed the research and inspection method in the books of al-Jarh and al-Ta’deel to investigate the mixed people who did not narrate after the mixing, whether it was from themselves, their families, or the narrators on their authority, then I studied their conditions and the critics’ sayings about them before the mixing

Aspek Hukum Pidana Perampasan Jenazah Akibat Covid-19 Menurut Undang-Undang Nomor 6 Tahun 2018 Tentang Kekarantinaan Kesehatan

Introduction: The community plays an important role in complying with Government regulations and policies in suppressing the chain of transmission of Covid-19, for example, wearing masks, maintaining cleanliness, washing hands, and so on.Purposes of the Research: The purpose of this study is to provide an overview of the qualifications of the crime of taking the corpse of Covid-19 according to the statutory regulations and the obstacles to investigating the crime of taking the body of Covid-19.Methods of the Research: Research methods are used with normative juridical research types. The problem approach used is the legal approach, concept analysis approach, case approach, Source of legal materials used primary legal materials and secondary legal materials. Collection techniques through literature studies and then analyzed through the way of description using qualitative methods. Result of the Research: The results of this study show that a criminal act of confiscating a corpse due to Covid-19 was committed by unscrupulous residents of Batu Merah Village, Ambon City. In the Judge's decision, the defendants had fulfilled the criminal element, namely the existence of actions from everyone who did not comply with the implementation and/or obstructed the implementation so that it caused a Public Health Emergency. With the higher rate of transmission of the virus, investigators are afraid to face face to face to examine suspects or witnesses. Therefore, the government needs to make specific regulations regarding the criminal act of confiscating the corpse of Covid-19.

Molecular determinants of multidrug-resistant tuberculosis in Sierra Leone.

A substantial proportion of MDR-TB strains in Sierra Leone were resistant against all first line drugs; however this makes the all-oral-six-month BPaLM regimen or other 6-9 months all oral regimens still viable, mainly because there was no FQ resistance.Resistance to BDQ was detected, as well as RR, due to mutations outside of the hotspot region. While the prevalence of those resistances was low, it is still cause for concern and needs to be closely monitored.

More different than alike: cross-sector volatility spillovers in Chinese stock sectors during COVID-19 pandemic

ABSTRACT The asymmetric spillovers and dynamic connectedness among sectors in Chinese stock market have not been fully studied, especially the impact of catastrophic events related to the COVID-19 pandemic on the linkages. In this paper, an asymmetric VAR-BEKK (DCC) – GARCH model is employed to measure the volatility spillovers and dynamic correlations among Chinese stock sectors before and during the COVID-19 pandemic. The empirical results indicate that volatility spillovers among sectors are significant, with evident differences before and during COVID-19. To be specific, the primary spillover transmitting sector has shifted from telecom business for the pre-pandemic period to the financial real estate sector after the outbreak. However, the role of the raw materials sector as the spillover receiver has not changed. Notably, the medical health sector forms closed-loop chains of transmission with the most other sectors during the COVID-19 period. In addition, asymmetric volatility spillovers and dynamic correlations among stock sectors are also significantly examined. The findings contribute to investors and decision makers in adjusting trading strategies and monitoring market risks.

KEJADIAN LUAR BIASA POLIOMIELITIS DI INDONESIA PADA TAHUN 2022-2023: SUATU TINJAUAN

Indonesia achieved polio eradication along with several other members of the Southeast Asia Regional Organization (SEARO) in 2014 because it succeeded in overcoming the disease caused by the wild polio virus. Unfortunately since then Indonesia has experienced several reported outbreaks. This literature review aims to analyze the factors causing the re-emergence of poliomyelitis in Indonesia after being declared polio-free in 2014 and effective steps to stop outbreaks and prevent the re-emergence of poliomyelitis. Awareness of health workers and the public regarding polio must be increased so that Indonesia and the world can soon be polio-free. The last two outbreaks occurred in Indonesia in 2022 and 2023. The first outbreak in 2022 was in Pidie Regency, Aceh, Indonesia. In response to the poliomyelitis outbreak, the government immediately launched a simultaneous vaccination program. Since then no cases of poliomyelitis have been found until another case was found in December 2023 in Solo, Central Java, Indonesia. Once again, to respond to the poliomyelitis outbreak, the government held a simultaneous vaccination program in three districts, namely Pamekasan and Sampang, East Java and Klaten, Central Java. Followed after that by all regions in Central Java and East Java. It is expected that this quick response from the government can stop the outbreak again. The target of SubPIN (National Immunization Subweek) is to break the chain of transmission, so it must ensure that Outbreaks Response Immunization (ORI) coverage is high at least 95% and evenly distributed throughout the region. Apart from that, information to the public regarding the dangers of disease and the importance of complete vaccination to prevent disease must continue to be provided.

Types of Hadiths that have been Weak by Hadith Scholars in Terms of the Authenticity of the Chain of Transmission and the Correctness of the Meaning

The importance of the research lies in that it studies an innovative idea that will benefit both specialists and non-specialists, which is collecting the types of hadith contained in the words of scholars with refutation and explanation, in terms of the accuracy of the attribution to the Messenger of God, peace be upon him, or others. In terms of the validity of the meaning, for this reason, the research can be like an introduction to books on weak and fabricated (and false) hadiths. The research used the inductive and analytical method, and arrived at fifteen types, which can be summarized in the following points: 1- Weak and fabricated hadiths that are not authentically narrated from the Prophet, peace be upon him. Not all of them have a rejected meaning. Rather, some of them have a rejected meaning, and some have an acceptable meaning, either because the hadith agrees with the experiences and wisdom of nations, or agrees with other legal texts, or correct medicine, or Other than that. 2- The hadith in the words of the scholars may come across as completely weak, but they only mean part of the hadith. Because it came together in the text, and has two forms: The first form: The hadith consists of two parts, one of which is correct in its attribution to the Messenger of God, peace be upon him, and it is correct in meaning. The other part of it is refuted in its attribution and meaning. As for the second form: the hadith consists of two parts, one of which is correct in its ratio and meaning, and the other part of it is correct in meaning, but it is refuted by its attribution to the Messenger of God, peace be upon him. 3- The hadith may have a neutral meaning, that is, it is not described as being in accordance with the principles or contrary to it, but rather it adds a description of the unseen, or a new jurisprudential description. It is narrated with a weak chain of transmission or an abandoned narrator. For this hadith, the researcher only has the chain of transmission to verify it, and the meaning has no clear impact on knowing its authenticity or weakness. 4- The hadith may be authentic, but it has another wording in which one word has been replaced, and the reader will find it in the books of weak hadiths, even though it is authentic without this replaced word. 5- The reader may find a hadith condemned to be refuted in the books of fabricated and weak ones, and it is authentic on the authority of the Prophet, peace be upon him, but they weaken it if it is based on the narration of a companion other than the companion for whom he is famous. 6- The reader may find a hadith condemned to be refuted in the books of fabricated and fabricated ones whose attribution to the Messenger of God, peace be upon him, is not correct, but it is correct to attribute it to one of the companions, with a chain of narrators attributed to it, or one of the followers. 7- The hadith may be authentic, and there is another hadith related to it that may be authentic, but it is not valid as a reason for the first hadith. 8- Scholars may weaken the hadith, and do not mean its text, but rather they mean the narration in which it describes the sequence in it.

Using big sequencing data to identify chronic SARS-Coronavirus-2 infections

The evolution of SARS-Coronavirus-2 (SARS-CoV-2) has been characterized by the periodic emergence of highly divergent variants. One leading hypothesis suggests these variants may have emerged during chronic infections of immunocompromised individuals, but limited data from these cases hinders comprehensive analyses. Here, we harnessed millions of SARS-CoV-2 genomes to identify potential chronic infections and used language models (LM) to infer chronic-associated mutations. First, we mined the SARS-CoV-2 phylogeny and identified chronic-like clades with identical metadata (location, age, and sex) spanning over 21 days, suggesting a prolonged infection. We inferred 271 chronic-like clades, which exhibited characteristics similar to confirmed chronic infections. Chronic-associated mutations were often high-fitness immune-evasive mutations located in the spike receptor-binding domain (RBD), yet a minority were unique to chronic infections and absent in global settings. The probability of observing high-fitness RBD mutations was 10-20 times higher in chronic infections than in global transmission chains. The majority of RBD mutations in BA.1/BA.2 chronic-like clades bore predictive value, i.e., went on to display global success. Finally, we used our LM to infer hundreds of additional chronic-like clades in the absence of metadata. Our approach allows mining extensive sequencing data and providing insights into future evolutionary patterns of SARS-CoV-2.

Agrotourism Business Development Strategy “Eptilu” in Garut Regency

Agrotourism is one of the most popular tourism concepts in Indonesia. During the pandemic, many agrotourism closed permanently due to government regulations such as PSBB and PPKM that prohibit community activities outside their house. This regulation is strictly enforced as on the efforts to cut off the chain of transmission of Covid-19 itself. This study aims to help formulate business strategies that can be implemented in Eptilu Agrotourism as an effort to improve business and also gain a wide market share. Data was obtained from observations, direct interviews and questionnaires. The number of internal respondents for Eptilu Agrotourism was 10 people, while the number of respondents to analyze the level of visitor satisfaction was 78 visitor respondents. This research method uses qualitative and quantitative methods with various analytical tools such as internal analysis using IFE matrix, external analysis using EFE matrix and IPA, IE matrix, SWOT matrix, and QSPM matrix. The results showed that nine strategy proposals were obtained and sorted by priority. The main priority strategy that emerged was related to human resource development in Eptilu Agrotourism. Keywords: agrotourism, business strategy, new normal, pandemic, qspm

Perlindungan Hukum terhadap Investor Perseroan Terbatas Akibat Pandemi Covid-19

The Coronavirus Disease 2019 (Covid-19) pandemic has prompted countries, including Indonesia, to implement 'abnormal' policies to break the chain of transmission. One approach is the normative juridical method, which involves analyzing and studying relevant laws and regulations to address issues. Legal protection is essential for improving law enforcement and ensuring stability, including in economic and legal matters. Good corporate governance principles are upheld within the Limited Liability Company. Presidential Regulation No. 44 of 2016 lists Closed and Open Business Sectors with Investment Requirements.

Increase in invasive group A streptococcal infections in Milan, Italy: a genomic and clinical characterization.

Group A Streptococcus (GAS) causes multiple clinical manifestations, including invasive (iGAS) or even life-threatening (severe-iGAS) infections. After the drop in cases during COVID-19 pandemic, in 2022 a sharp increase of GAS was reported globally. GAS strains collected in 09/2022-03/2023 in two university hospitals in Milan, Italy were retrospectively analyzed. Clinical/epidemiological data were combined with whole-genome sequencing to: (i) define resistome/virulome, (ii) identify putative transmission chains, (iii) explore associations between emm-types and clinical severity. Twenty-eight isolates were available, 19/28 (67.9%) from adults and 9/28 (32.1%) from pediatric population. The criteria for iGAS were met by 19/28 cases (67.9%), of which 11/19 (39.3%) met the further criteria for severe-iGAS. Pediatric cases were mainly non-invasive infections (8/9, 88.9%), adult cases were iGAS and severe-iGAS in 18/19 (94.7%) and 10/19 (52.6%), respectively. Thirteen emm-types were detected, the most prevalent being emm1 and emm12 (6/28 strains each, 21.4%). Single nucleotide polymorphism (SNP) analysis of emm1.0 and emm12.0 strains revealed pairwise SNP distance always >10, inconsistent with unique transmission chains. Emm12.0-type, found to almost exclusively carry virulence factors speH and speI, was mainly detected in children and in no-iGAS infections (55.6 vs. 5.3%, p = 0.007 and 66.7 vs. 0.0%, p < 0.001, respectively), while emm1.0-type was mainly detected in severe-iGAS (0.0 vs. 45.5%, p = 0.045). This study showed that multiple emm-types contributed to a 2022/2023 GAS infection increase in two hospitals in Milan, with no evidence of direct transmission chains. Specific emm-types could be associated with disease severity or invasiveness. Overall, these results support the integration of classical epidemiological studies with genomic investigation to appropriately manage severe infections and improve surveillance.

Importance of National Influenza Centers in the surveillance of highly pathogenic avian viruses. The time for One-Health is now

Since 1996, the highly pathogenic avian influenza subtype A(H5N1) has been causing almost uninterrupted outbreaks in wild and domestic birds, as well as cases in humans with a mortality rate close to 50%. However, the years of greatest circulation have been precisely the years following the COVID-19 pandemic, in which several cases have been recorded in humans in places where they had never appeared before, in addition to multiple cases in wild, domestic and peri-domestic mammals, which raise some concern about the risk that the virus may jump to humans through chains of transmission of greater or lesser extent. The current outbreak of A(H5N1) shows us that the One-Health concept should be more alive than ever to join efforts between professionals from different sectors of human, animal and environmental health to avoid or minimize these risks, so that reference laboratories such as the National Influenza Centers have the human and material resources to provide rapid and relevant information in the shortest possible time before emergencies of this type. The diagnostic and monitoring tools to be used in these cases must be available for any eventuality, and going beyond the basic data must be an indispensable premise to be able to carry out a detailed monitoring that serves to limit outbreaks, limit the spread of the disease, and help in the design of future pandemic vaccines against avian viruses.

Problems of interpreting the main types of hadith in terms of their correct understanding

Relevance. This study provides traditional insights into the hadith and Sunnah of the Prophet Muhammad as an important source of Islamic religion and Muslim culture in general. All the Prophet's activities are covered by the Sunnah, which was, remains and will remain one of the main sources of Muslim law, secondary solely to the Holy Koran.Purpose. The purpose of the study was to conduct a systematic analysis of the stages of hadith study based on Sheikh Abdullah Harare's theology and to draw attention to the complexity of the science of hadith.Methodology. The methodology for analysing the veracity and accuracy of the hadith of the Prophet Muhammad involves a set of specific procedures and activities.Results. This study covers topics such as the concept of hadith, its meaning, hadith teaching and distribution, recording, the Isnad system, criticism of hadith, the classification of scholars and its impact on the classification of hadith, fabrication of hadith, etc. The types of hadith in terms of the credibility of the chain of transmitters and the authenticity of the texts were investigated. Each type of hadith is unique. Thus, every scholar, theologian, orientalist and ordinary reader of the hadith before diving into this science must be more or less familiar with it unless he wants to go down the wrong path.Conclusions. People have always distorted texts when passing them on or translating them to one another. Sometimes these distortions occurred unintentionally and sometimes deliberately. The science of hadith helps to clearly assess each individual expression attributed to the Prophet Muhammad in terms of its veracity. The task of hadith scholars is to determine the truth of hadith. Only after examining the biographies of the people mentioned in the Isnad (chain of transmissions) to convince them of their positive moral and intellectual qualities it is possible to judge the authenticity of a particular hadith.

Differentiating behavioral impact with or without vaccination certification under mass vaccination and non-pharmaceutical interventions on mitigating COVID-19

As COVID-19 vaccines became widely available worldwide, many countries implemented vaccination certification, also known as a “green pass”, to promote and expedite vaccination on containing virus spread from the latter half of 2021. This policy allowed those vaccinated to have more freedom in public activities compared to more constraints on the unvaccinated in addition to existing non-pharmaceutical interventions (NPIs). Accordingly, the vaccination certification also induced heterogeneous behaviors of unvaccinated and vaccinated groups. This makes it essential yet challenging to model the behavioral impact of vaccination certification on the two groups and the transmission dynamics of COVID-19 within and between the groups. Very limited quantitative work is available for addressing these purposes. Here we propose an extended epidemiological model SEIQRD^2 to effectively distinguish the behavioral impact of vaccination certification on unvaccinated and vaccinated groups through incorporating two contrastive transmission chains. SEIQRD^2 also quantifies the impact of the green pass policy. With the resurgence of COVID-19 in Greece, Austria, and Israel in 2021, our simulation results indicate that their implementation of vaccination certification brought about more than a 14-fold decrease in the total number of infections and deaths as compared to a scenario with no such a policy. Additionally, a green pass policy may offer a reasonable practical solution to strike the balance between public health and individual’s freedom during the pandemic.

Transmission chains of the first local outbreak cause by Delta VariantB.1.617.2 COVID-19 in Guangzhou, Southern China

BackgroundThe first local outbreak of Delta Variant B.1.617.2 COVID-19 of China occurred in Guangzhou city, south China, in May 2021. This study analyzed the transmission chains and local cluster characteristics of this outbreak, intended to provide information support for the development and adjustment of local prevention and control strategies.MethodsThe transmission chains and local cluster characteristics of 161 local cases in the outbreak were described and analyzed. Incubation period, serial interval and generation time were calculated using the exact time of exposure and symptom onset date of the cases. The daily number of reported cases and the estimated generation time were used to estimate the effective reproduction number (Rt).ResultsWe identified 7 superspreading events who had more than 5 next generation cases and their infected cases infected 70.81%(114/161) of all the cases transmission. Dining and family exposure were the main transmission routes in the outbreak, with 29.19% exposed through dining and 32.30% exposed through family places. Through further analysis of the outbreak, the estimated mean incubation period was 4.22 (95%CI: 3.66–4.94) days, the estimated mean generation time was 2.60 (95%CI: 1.96–3.11) days, and the estimated Rt was 3.29 (95%CI: 2.25–5.07).ConclusionsClassification and dynamically adjusted prevention and control measures had been carried out according to analysis of transmission chains and epidemical risk levels, including promoting nucleic acid screening at different regions and different risk levels, dividing closed-off area, controlled area according to the risk of infection, raising the requirements of leaving Guangzhou. By the above control measures, Guangzhou effectively control the outbreak within 28 days without implementing a large-scale lockdown policy.

Factors affecting subsequent dose of COVID-19 vaccine uptake based on BASNEF model among older adults

BackgroundVaccination is a primary prevention approach to preventing disease by disconnecting the transmission chain. The current study utilized a BASNEF model framework to identify factors influencing subsequent doses of COVID-19 vaccination among older adults.MethodsThis cross-sectional study was performed in the west of Iran in May 2022. The participants were selected via multi-stage sampling. Finally, 1120 participants contributed to the present study. The questionnaire consisted of three sections: a) Socio-demographic characteristics, b) cognitive impairments tests, and c) Questionnaire about the subsequent dose of COVID-19 vaccine uptake based on the BASNEF model. Data were analyzed using the software IBM AMOS-20 and SPSS-23 via one-way analysis of variance (ANOVA) and independent sample T-tests were used, too. The significance level of statistical tests was regarded as less than 0.05.ResultsThe presented results of analyzing 50% of the variance of vaccination intention as the dependent variable (R square = 0.497) and 10% of the behavior variance as the dependent variable (R square = 0.104) can be explained based on the BASNEF model. The enabling factors (β = 0.636, p < 0.001) and the intention (β = 0.322, p < 0.001) were important factors for subsequent doses of COVID-19 vaccine uptake in older adults.ConclusionSo, planning and implementing promotional intervention programs for older people (over 65; 80), females, illiterate, widows and divorced, good economic status, and urban areas is essential. It seems that enabling factors such as free vaccinations, vaccination inaccessible places such as public social security agencies, social supports such as involvement of the government and physicians, and improving information by the medium or knowledge-sharing experience, which can be further used to enhance the acceptance of subsequent doses of COVID-19 uptake in older adults.

Clade I-Associated Mpox Cases Associated with Sexual Contact, the Democratic Republic of the Congo.

We report a cluster of clade I monkeypox virus infections linked to sexual contact in the Democratic Republic of the Congo. Case investigations resulted in 5 reverse transcription PCR-confirmed infections; genome sequencing suggest they belonged to the same transmission chain. This finding demonstrates that mpox transmission through sexual contact extends beyond clade IIb.

Whole-genome sequencing-based genetic diversity, transmission dynamics, and drug-resistant mutations in Mycobacterium tuberculosis isolated from extrapulmonary tuberculosis patients in western Ethiopia.

Extrapulmonary tuberculosis (EPTB) refers to a form of Tuberculosis (TB) where the infection occurs outside the lungs. Despite EPTB being a devastating disease of public health concern, it is frequently overlooked as a public health problem. This study aimed to investigate genetic diversity, identify drug-resistance mutations, and trace ongoing transmission chains. A cross-sectional study was undertaken on individuals with EPTB in western Ethiopia. In this study, whole-genome sequencing (WGS) was employed to analyze Mycobacterium tuberculosis (MTB) samples obtained from EPTB patients. Out of the 96 genomes initially sequenced, 89 met the required quality standards for genetic diversity, and drug-resistant mutations analysis. The data were processed using robust bioinformatics tools. Our analysis reveals that the majority (87.64%) of the isolates can be attributed to Lineage-4 (L4), with L4.6.3 and L4.2.2.2 emerging as the predominant sub-lineages, constituting 34.62% and 26.92%, respectively. The overall clustering rate and recent transmission index (RTI) were 30 and 17.24%, respectively. Notably, 7.87% of the isolates demonstrated resistance to at least one anti-TB drug, although multi-drug resistance (MDR) was observed in only 1.12% of the isolates. The genetic diversity of MTBC strains in western Ethiopia was found to have low inter-lineage diversity, with L4 predominating and exhibiting high intra-lineage diversity. The notably high clustering rate in the region implies a pressing need for enhanced TB infection control measures to effectively disrupt the transmission chain. It's noteworthy that 68.75% of resistance-conferring mutations went undetected by both GeneXpert MTB/RIF and the line probe assay (LPA) in western Ethiopia. The identification of resistance mutations undetected by both GeneXpert and LPA, along with the detection of mixed infections through WGS, emphasizes the value of adopting WGS as a high-resolution approach for TB diagnosis and molecular epidemiological surveillance.

Design and utilization of thrust fluctuation of slotted-tubular permanent magnet linear motor: Mechatronics for low-frequency vibration forming machine

Usually, the conventional low-frequency vibration forming machine has a main transmission mechanism as the driving source to provide forming force and an auxiliary mechanism as the vibration source to generate vibration force. The transmission chain is long and the structure is complex and bloated, which affects the forming process and product quality. This paper presents a novel mechatronics idea of low-frequency vibration forming machine, which uses a slotted tubular permanent magnet synchronous linear motor (slotted-TPMLM) as both the driving source and the vibration source. The key is that the slotted-TPMLM provides sufficient forming force accompanied with a certain low-frequency vibration force. Consequently, this paper focuses on the thrust fluctuation caused by the structure. Firstly, the effect of end force and the influence of cogging force are discussed in detail through Fourier analyses, especially the stator adjustment length and pole-slot combination. Then, the slotted-TPMLM is designed, manufactured, and tested. The results show that the slotted-TPMLM can provide a certain low-frequency vibration force (low frequency of 4.8 Hz at 100 mm/s and 48 Hz at 1000 mm/s), which meets the technical requirements. Consequently, the feasibility of the novel mechatronics idea of a low-frequency vibration forming machine has been verified. This research will contribute to the field of linear motors and metal forming machines.