A Survey on Some Parameters of Beef and Buffalo Meat Quality

A survey was carried out on 13 Vietnamese Yellow cattle, 14 LaiSind cattle and 18 buffalos in Hanoi to estimate the quality of longissimus dorsi in terms of pH, color, drip loss, cooking loss and tenderness at 6 different postmortem intervals. It was found that the pH value of longissimus dorsi was not significantly different among the 3 breeds (P>0.05), being reduced rapidly during the first 36 hours postmortem, and then stayed stable. The value was in the range that was considered to be normal. Conversely, the color values L*, a* and b* tended to increase and also stable at 36 hours postmortem, except that for LaiSind cattle at 48 hours. According to L* scale, the meat of Yellow and LaiSind cattle met the normal quality but the buffalo meat was considered to be dark cutters. The tenderness of longissimus dorsi was significantly different among the breeds (P<0.05). The value was highest at 48 hours and then decreased for LaiSind and buffalo, but for Yellow cattle the value decreased continuously after slaughtering In terms of tenderness buffalo meat and Yellow cattle meat were classified as “intermediate”, while LaiSind meat was out of this interval and classified as “tough”. Drip loss ratio was increased with the time of preservation (P<0.05). The cooking loss ratio was lowest at 12 hours and higher at the next period, but there was no significant difference among the periods after 36 hours postmotem.Peer reviewe

Kinematic and dynamic modelling for a class of hybrid robots composed of m local closed-loop linkages appended to an n-link serial manipulator

Recently, more and more hybrid robots have been designed to meet the increasing demand for a wide spectrum of applications. However, development of a general and systematic method for kinematic design and dynamic analysis for hybrid robots is rare. Most publications deal with the kinematic and dynamic issues for individual hybrid robots rather than any generalization. Hence, in this paper, we present a novel method for kinematic and dynamic modelling for a class of hybrid robots. First, a generic scheme for the kinematic design of a general hybrid robot mechanism is proposed. In this manner, the kinematic equation and the constraint equations for the robot class are derived in a generalized case. Second, in order to simplify the dynamic modelling and analysis of the complex hybrid robots, a Lemma about the analytical relationship among the generalized velocities of a hybrid robot system is proven in a generalized case as well. Last, examples of the kinematic and dynamic modelling of a newly designed hybrid robot are presented to demonstrate and validate the proposed method

SOME METEO - HYDRO - DYNAMICAL FEATURES IN MEKONG RIVER MOUTH AREA

This paper provides some meteo-hydro-dynamical features in Mekong River Mouth area which were based on statistical results from longtime measurement data such as wind, wave, sea water level, and river discharge. Study results show that distribution features of wind and wave characteristics are corresponding to seasonal variation. Predominant wind and wave directions during NE Monsoon period is NE, and in W, SW directions during SW Monsoon period. NE Monsoon period is from November to April (strongest in December and January), SW Monsoon period is from June to September (strongest in August). During NE Monsoon period the wind velocity and wave height were higher than that of SW Monsoon period. Variation of SWL at Vungtau Station shows that the tide is semi-diurnal with maximum value occurred during NE monsoon period (highest in November), and minimum value occurred during SW Monsoon period (lowest in June). Variation of river discharge is similarly at two stations (Mythuan and Cantho). During flood season (from July to December) average monthly discharge was ranged from 4,000 to 15,800 m3/s. During dry season (from January to May) average monthly discharge at both stations was less than 4,000 m3/s. Statistical data show that Mekong River Mouth area is a region of strong and complicated hydro-dynamical interaction processes between river and sea. Key words: Monsoon, North-East (NE), South-West (SW), Sea Water Level (SWL), River discharge, Mekong River

ベトナムにおけるヤマノイモ遺伝資源共同探索調査

A collaborative exploration for yam genetic resource in Vietnam was conducted with the Ministry of Agriculture and Rural Development (MARD) from Oct. 31 to Nov. 30, 2005. We visited northern mountain area of Vietnam near the border of China. This mission surveyed Son La Province, Lai Chau Province, Lao Cai Province, Ha Giang Province and Cao Bang Province. As a result, we collected 24 accessions in this exploration : 9 Dioscorea alata, 4 Dioscorea esculenta, 1 Dioscorea persimilos, 1 Dioscorea bulbifera, 1 Dioscorea cirrhosa, 1 probably Dioscorea japonica, 7 Dioscorea sp. (wild species). These passport dates of the collected materials are summarized in Table 3

ĐẶC ĐIỂM DÒNG CHẢY VEN BỜ BẮC TRUNG BỘ (HÀ TĨNH - THỪA THIÊN-HUẾ) THỜI KỲ 4/2016

This paper presents the modeled results of general current pattern (daily average value) in Northern Central Vietnam Coast (Ha Tinh - Thua Thien-Hue) during April 2016. Study results show that in general, current flowed from the North to the South with small and instable velocity (V ≈ 0.1 - 0.2 m/s). From 2nd to 6th April current flowed from the South to the North. From 7th to 29th April current flowed from the North to the South. During 13rd to 16th April current velocity was weak (V ≤ 0.1 m/s). In the southern region of Thua Thien-Hue province, the direction of current was instable (from 6th to 9th and from 20th to 22nd April current flowed from the South to the North). Current distribution pattern from modeled results was in accordance with the propagation characteristics of surface water temperatures in the studied area through data analysis of satellite images.Bài báo trình bày kết quả tính toán trường dòng chảy tổng hợp trung bình ngày cho khu vực ven bờ Bắc Trung Bộ (Hà Tĩnh - Thừa Thiên-Huế) thời kỳ 4/2016. Kết quả nghiên cứu cho thấy trong thời gian nghiên cứu nhìn chung dòng chảy tổng hợp trung bình ngày có hướng từ bắc xuống nam, tốc độ tương đối nhỏ V ≈ 0,1 - 0,2 m/s và không ổn định. Từ 2-6/4/2016 dòng chảy tổng hợp trung bình ngày ven bờ có hướng từ nam lên bắc. Từ 7-29/4/2016 dòng chảy ven bờ có hướng từ bắc xuống nam. Các ngày 13-16/4/2016 dòng chảy tổng hợp trung bình ngày có tốc độ nhỏ (V ≤ 0,1 m/s). Khu vực phía nam Thừa Thiên-Huế dòng chảy tổng hợp trung bình ngày có hướng bị biến động mạnh nhất (các ngày 6-9/4 và 20-22/4 hướng dòng từ nam lên bắc). Đặc điểm phân bố dòng chảy tính toán tương đối phù hợp với đặc điểm lan truyền nhiệt độ nước tầng mặt tại khu vực nghiên cứu qua số liệu phân tích ảnh vệ tinh

Real time inverse kinematics of a general 5-axis CNC machine

In most of the previous investigations, the kinematics model of five-axis computer-numerical control (CNC) centers was formulated just at the position level, and the differential kinematic relationships (velocity, acceleration and jerk of the five joints of a five-axis center) that are necessary for several purposes, especially for investigating the relationship between the limits of a machine’s drives and the feed rate maximization (the productivity maximization), have been overlooked. Therefore, this paper addresses the differential kinematic modelling and analysis for the five-axis CNC centers. In particular, the differential kinematic equations are formulated in a parametric domain so that they are useful for investigating the kinematic behaviors of the five-axis centers in real time

Identifying Live Bird Markets with the Potential to Act as Reservoirs of Avian Influenza A (H5N1) Virus: A Survey in Northern Viet Nam and Cambodia

Wet markets are common in many parts of the world and may promote the emergence, spread and maintenance of livestock pathogens, including zoonoses. A survey was conducted in order to assess the potential of Vietnamese and Cambodian live bird markets (LBMs) to sustain circulation of highly pathogenic avian influenza virus subtype H5N1 (HPAIV H5N1). Thirty Vietnamese and 8 Cambodian LBMs were visited, and structured interviews were conducted with the market managers and 561 Vietnamese and 84 Cambodian traders. Multivariate and cluster analysis were used to construct a typology of traders based on their poultry management practices. As a result of those practices and large poultry surplus (unsold poultry reoffered for sale the following day), some poultry traders were shown to promote conditions favorable for perpetuating HPAIV H5N1 in LBMs. More than 80% of these traders operated in LBMs located in the most densely populated areas, Ha Noi and Phnom Penh. The profiles of sellers operating at a given LBM could be reliably predicted using basic information about the location and type of market. Consequently, LBMs with the largest combination of risk factors for becoming virus reservoirs could be easily identified, potentially allowing control strategies to be appropriately targeted. These findings are of particular relevance to resource-scarce settings with extensively developed LBM systems, commonly found in South-East Asia

Spatiotemporal evolution of SARS-CoV-2 Alpha and Delta variants during large nationwide outbreak of COVID-19, Vietnam, 2021

We analyzed 1,303 SARS-CoV-2 whole-genome sequences from Vietnam, and found the Alpha and Delta variants were responsible for a large nationwide outbreak of COVID-19 in 2021. The Delta variant was confined to the AY.57 lineage and caused >1.7 million infections and >32,000 deaths. Viral transmission was strongly affected by nonpharmaceutical interventions

Effets d’échelle statistiques sur la résistance à rupture en compression du béton

Size effects on mechanical strength, i.e. the fact that larger structures fail under lower stresses than smaller ones, already highlighted by Leonardo da Vinci and Edmée Mariotte centuries ago, remain nowadays a crucial problem to establish structural design rules and safety regulations from an upscaling of laboratory data. These size effects are generally explained either from a deterministic energetic approach that predicts a non-vanishing asymptotic strength but, by construction, does not account for fluctuations around the mean strength and their size dependence, or from a statistical approach based on the weakest-link theory that implies a vanishing strength towards large scales.Recently, an alternative framework has been proposed based on an interpretation of compressive failure of heterogeneous materials as a critical transition from an intact to a failed state. This critical interpretation releases the underlying hypotheses of the weakest-link theory, pure brittleness and the independence of damage events, while predicting a non-vanishing asymptotic mean strength (σ_∞ ) but vanishing intrinsic fluctuations at large scales. The application this framework to the statistical size effects on compressive strength of concrete, a typical quasibrittle material of tremendous importance in civil engineering, is investigated in this thesis.From an extensive series of uniaxial compression experiments (527 tests) carried out on concrete samples with four different sizes and three different microstructures, we demonstrate (i) the failure of the weakest-link theory in this case, and instead (ii) the pertinence of the critical framework to account for size effects on compressive strength of concrete, in terms of average strength, associated fluctuations, and probability of failure. From a detailed analysis of the microstructural disorder of our materials, we show that the pore structure, rather than the concrete mix, plays a significant role on size effects on strength. In this framework, the asymptotic strength (σ_∞ ) represents the genuine characteristic compressive strength (f_ck ) of the material, a key property for the dimensioning large-scale structures from an upscaling of small-scale laboratory mechanical tests and for the quality control of concrete.As a consequence of the leading role of the pore structure in controlling the size effects on compressive strength of low-porosity concretes, when estimating the characteristic (asymptotic) strength from a series of tests with a single sample size, a condition on this size with respect to the characteristic scale of pore structure is proposed to be fulfilled.Les effets d’échelle sur la résistance mécanique des matériaux, i.e. le fait que plus un échantillon de matière est grand, plus, en moyenne, sa contrainte à rupture sera faible, déjà soulignées par Leonardo da Vinci et Edmée Mariotte il y a des siècles, demeurent de nos jours un problème crucial pour établir des règles de sécurité et de conception de grandes structures à partir de données de laboratoire. Ces effets d’échelle sont généralement expliqués soit par une approche déterministe qui prédit une résistance asymptotique non nulle mais, par construction, ne tient pas compte des fluctuations de la résistance moyenne et de leur dépendance vis-à-vis de la taille, ou d'une approche statistique basée sur la théorie du maillon le plus faible qui implique une résistance nulle pour un système de taille infini.Récemment, un cadre alternatif a été proposé sur la base d’une interprétation de la rupture en compression des matériaux hétérogènes comme une transition de phase critique entre un état intact et un état rompu. Cette interprétation libère les hypothèses de base de la théorie du maillon le plus faible comme la fragilité extrême et l’indépendance entre évènements de microfracturation et prédit qu’un système de taille infinie conservera une résistance mécanique non nulle (σ_∞ ) mais une variabilité associée de la résistance nulle. En appliquant ce cadre critique, les effets d’échelle statistique sur la résistance en compression du béton, un matériau quasi-fragile typique et important en génie civil, sont étudiés dans cette thèse.A partir d’une importante série d’expériences de compression uniaxiale (527 essais) qui a été réalisée sur des échantillons du béton de quatre tailles différentes et trois microstructures différentes, nous démontrons (i) l’échec de la théorie du maillon le plus faible dans ce cas ; et au lieu de cela (ii) la pertinence du cadre critique pour tenir compte des effets d’échelle sur la résistance à rupture en compression du béton, en termes de valeur moyenne, de fluctuation associées et de probabilité de défaillance. A partir d’une analyse détaillée de la microstructure de nos matériaux, nous montrons que la structure des pores, plutôt que les aggrégats, joue un rôle important sur les effets d’échelle sur la résistance à rupture en compression. Dans ce cadre, la résistance asymptotique (σ_∞ ) représente la véritable résistance caractéristique en compression (f_ck ), qui est une propriété essentielle pour la conception de structures à grande échelle et pour le contrôle de la qualité du béton.En conséquence du rôle important de la structure des pores sur les effets d’échelle sur la résistance en compression des bétons à faible porosité, lors de l'estimation de la résistance caractéristique à partir d'une série d'essais avec une seule taille d'échantillon, une condition sur cette taille par rapport à la taille caractéristique de la structure des pores est proposée

Effets d’échelle statistiques sur la résistance à rupture en compression du béton

Size effects on mechanical strength, i.e. the fact that larger structures fail under lower stresses than smaller ones, already highlighted by Leonardo da Vinci and Edmée Mariotte centuries ago, remain nowadays a crucial problem to establish structural design rules and safety regulations from an upscaling of laboratory data. These size effects are generally explained either from a deterministic energetic approach that predicts a non-vanishing asymptotic strength but, by construction, does not account for fluctuations around the mean strength and their size dependence, or from a statistical approach based on the weakest-link theory that implies a vanishing strength towards large scales.Recently, an alternative framework has been proposed based on an interpretation of compressive failure of heterogeneous materials as a critical transition from an intact to a failed state. This critical interpretation releases the underlying hypotheses of the weakest-link theory, pure brittleness and the independence of damage events, while predicting a non-vanishing asymptotic mean strength (σ_∞ ) but vanishing intrinsic fluctuations at large scales. The application this framework to the statistical size effects on compressive strength of concrete, a typical quasibrittle material of tremendous importance in civil engineering, is investigated in this thesis.From an extensive series of uniaxial compression experiments (527 tests) carried out on concrete samples with four different sizes and three different microstructures, we demonstrate (i) the failure of the weakest-link theory in this case, and instead (ii) the pertinence of the critical framework to account for size effects on compressive strength of concrete, in terms of average strength, associated fluctuations, and probability of failure. From a detailed analysis of the microstructural disorder of our materials, we show that the pore structure, rather than the concrete mix, plays a significant role on size effects on strength. In this framework, the asymptotic strength (σ_∞ ) represents the genuine characteristic compressive strength (f_ck ) of the material, a key property for the dimensioning large-scale structures from an upscaling of small-scale laboratory mechanical tests and for the quality control of concrete.As a consequence of the leading role of the pore structure in controlling the size effects on compressive strength of low-porosity concretes, when estimating the characteristic (asymptotic) strength from a series of tests with a single sample size, a condition on this size with respect to the characteristic scale of pore structure is proposed to be fulfilled.Les effets d’échelle sur la résistance mécanique des matériaux, i.e. le fait que plus un échantillon de matière est grand, plus, en moyenne, sa contrainte à rupture sera faible, déjà soulignées par Leonardo da Vinci et Edmée Mariotte il y a des siècles, demeurent de nos jours un problème crucial pour établir des règles de sécurité et de conception de grandes structures à partir de données de laboratoire. Ces effets d’échelle sont généralement expliqués soit par une approche déterministe qui prédit une résistance asymptotique non nulle mais, par construction, ne tient pas compte des fluctuations de la résistance moyenne et de leur dépendance vis-à-vis de la taille, ou d'une approche statistique basée sur la théorie du maillon le plus faible qui implique une résistance nulle pour un système de taille infini.Récemment, un cadre alternatif a été proposé sur la base d’une interprétation de la rupture en compression des matériaux hétérogènes comme une transition de phase critique entre un état intact et un état rompu. Cette interprétation libère les hypothèses de base de la théorie du maillon le plus faible comme la fragilité extrême et l’indépendance entre évènements de microfracturation et prédit qu’un système de taille infinie conservera une résistance mécanique non nulle (σ_∞ ) mais une variabilité associée de la résistance nulle. En appliquant ce cadre critique, les effets d’échelle statistique sur la résistance en compression du béton, un matériau quasi-fragile typique et important en génie civil, sont étudiés dans cette thèse.A partir d’une importante série d’expériences de compression uniaxiale (527 essais) qui a été réalisée sur des échantillons du béton de quatre tailles différentes et trois microstructures différentes, nous démontrons (i) l’échec de la théorie du maillon le plus faible dans ce cas ; et au lieu de cela (ii) la pertinence du cadre critique pour tenir compte des effets d’échelle sur la résistance à rupture en compression du béton, en termes de valeur moyenne, de fluctuation associées et de probabilité de défaillance. A partir d’une analyse détaillée de la microstructure de nos matériaux, nous montrons que la structure des pores, plutôt que les aggrégats, joue un rôle important sur les effets d’échelle sur la résistance à rupture en compression. Dans ce cadre, la résistance asymptotique (σ_∞ ) représente la véritable résistance caractéristique en compression (f_ck ), qui est une propriété essentielle pour la conception de structures à grande échelle et pour le contrôle de la qualité du béton.En conséquence du rôle important de la structure des pores sur les effets d’échelle sur la résistance en compression des bétons à faible porosité, lors de l'estimation de la résistance caractéristique à partir d'une série d'essais avec une seule taille d'échantillon, une condition sur cette taille par rapport à la taille caractéristique de la structure des pores est proposée