The rapidly increasing demand and the inefficacy of financing transportation infrastructure project investments have contributed to various challenges for Vietnam in recent decades. Since the country’s budget is inadequate for investing in all necessary infrastructure projects, the Vietnam government has been inviting other economic sectors, especially the private sector, to participate in infrastructure development. The cooperation between the government agencies and the private entities, called PublicPrivate Partnership (PPP), must encounter various challenges leading to difficulties in attracting private investors. A main reason is that private investors must deal with critical risks concerning PPP investment environment. It is a challenging task for the government to optimally manage such risks to enhance the attractiveness of PPP projects for private investors. This paper examines the critical risk factors that influence the private sector’s investment decisions on PPP transportation projects in Vietnam. Risk factors inherent in typical PPP projects were compiled by comprehensive literature review. To reflect unique characteristics of PPP projects in Vietnam, the compiled risk factors were reviewed by a group of PPP experts from both the public and private sectors in Vietnam through indepth interviews and questionnaire surveys. In addition, ten PPP project case studies in Vietnam were analyzed to derive the risk profile of PPP transportation projects of the nation. These risk factors were quantitatively assessed based on their probabilities and impact levels. We found that the critical risk factors of PPP infrastructure projects in Vietnam are acquisition/compensation problems, approvals and permits, inadequate feasibility studies, finance market issues, subjective evaluation methods, and change in laws and regulations. By performing factor analysis, these critical risk factors were grouped into four categories: (1) bidding process, (2) finance issues, (3) laws and regulations, and (4) project evaluation issues. These critical risk factors represent the obstacles that repel private investors from PPP transportation projects in Vietnam. Thus, the Vietnam government agencies should meticulously address these issues to attract both domestic and foreign private investors in PPP projects.
The main purpose of this study is to investigate the influence of tool geometry (cutting edge angle, rake angle, and inclination angle) and to optimize tool wear and surface roughness in hard turning of AISI 1055 (52HRC) hardened steel by using TiN coated mixed ceramic inserts. The results show that the inclination angle is the major factor affecting the tool wear and the surface roughness in hard turning. With the increase in negative rake and inclination angles, the tool wear decreases, and the surface roughness increases. However, the surface roughness will decrease when the inclination angle increases to overpass a certain limit. This is a new and significant point in the research of the hard turning process. From this result, the large negative inclination angle (λ = −10°) should be applied to reduce the surface roughness and the tool wear simultaneously. With the optimal cutting tool angles in the research, the hard machining process is improved remarkably with decreases of surface roughness and tool wear 8.3% and 41.3%, respectively in comparison with the standard tool angles. And the proposed tool-post design approach brings an effective method to change the tool insert angles using standard tool-holders to improve hard or other difficult-to-cut materials turning quality.
This paper identifies the concern factors of private investors associated with Public-Private Partnership (PPP) transportation projects in Vietnam. The concern factors are incorporated into four main groups: (1) company profile; (2) finance; (3) opportunities; and (4) risk perceptions. The paper examines the different perceptions by the public and private sectors about these concern factors adopted by experienced professionals related to PPP transportation projects. Based on a questionnaire survey in Vietnam, the most concern factors of private investors are their own capacity, demand issues, legal and political risks, long-term income, and financial sources issues of the PPP project. Moreover, five factors that represent the significant differences between the private and public sectors including political risks, enhancement of company’s strength in its industry, construction risks, demand issues, and financial viability of the company are also discovered. Addressing the different perceptions is indispensable to ensure the public sector can establish necessary policies that appeal to both domestic and foreign private investors. The paper at the same time hopes to provide some of lessons for the private sector.
“Dong trung ha thao Sapa” (DTHT) hard capsules prepared from Cordyceps militaris powder are intended to treat male hypogonadism. The aim of the current study was to evaluate the androgenic properties of this product on experimental animals. Weanling male rats and castrated peripubertal male rats were used for the study. Weanling male rats were divided into 5 groups: group I (saline-treated); group II (testosterone undecanoate-treated); group III (low dose DTHT capsules); and group IV (high dose DTHT capsules). Castrated peripubertal male rats were also divided into 5 groups: group I without castration (saline-treated); groups II to V were surgically castrated, group II (saline-treated); group III (testosterone undecanoate-treated), group IV (low dose DTHT capsules) and group V (high dose DTHT capsules). The potential effect was evaluated on five androgen-dependent tissue weight (seminal vesicles, ventral prostate, Cowper’s gland, glans penis, levator ani-bulbocavernosus - LABC muscle and the serum testosterone level in castrated rats. Five tissue weights and testes, epididymis weights were examined in weanling rats. A positive androgen agonist result should be a statistically significant increase (p ≤ 0.05) in any two or more of the five targets’ androgen-dependent tissue. The results suggest that capsules show androgenic properties in castrated male rats by increasing weight of 3 tissues (seminal vesicles, ventral prostate, LABC muscle). DTHT hard capsules appear to be an effective therapeutic drug for treating hypogonadism.
“Dong trung ha thao Sapa” (DTHT) capsules, prepared from Cordyceps militaris powder, are intended to be used in relieving menopausal signs and symptoms. The current study aimed to evaluate the estrogenic properties of DTHT capsules on experimental animals. Female mice from 6 to 8 weeks were used for the study. Mice were divided into the following groups: group I - normal control without being ovariectomized (saline-treated); group II to V were ovariectomized, group II (saline-treated); group III (Ethinyl estradiol-treated), group IV (low dose DTHT capsules) and group V (high dose DTHT capsules). The potential effect of DTHT capsules was evaluated by measuring both the wet and blotted uterus weights. The uterus was then fixed in 10% neutral buffered formalin, HE(Haematoxylin & Eosin) stained and examined histopathologically. The results suggest that DTHT capsules show estrogenic activity in ovariectomized mice by increasing wet uterus and blotted uterus weight and improving the uterus’s histology. DTHT capsules appear to be an effective therapeutic drug for the treatment of menopausal symptoms.
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