Judul: The Influence of Self-Concept and Purchasing Knowledge toward Consumer Vulnerability of E-Commerce Users
Abstrak: Kehadiran e-commerce memberikan banyak kemudahan dalam berbelanja, namun tidak dapat dipungkiri konsumen pun akan dekat dengan kerugian dan kerentanan akibat pelaku usaha atau karena kelemahan konsumen. Penelitian ini bertujuan untuk menganalisis faktor-faktor yang memengaruhi kerentanan konsumen, khususnya untuk pengguna e-commerce. Faktor-faktor tersebut di antaranya yaitu konsep diri dan pengetahuan pembelian dalam penggunaan e-commerce. Desain penelitian yang digunakan adalah cross-sectional study. Pemilihan contoh menggunakan non probability dengan metode self–administered menggunakan kuesioner online. Pengambilan data dilakukan pada bulan Maret 2021 selama tiga minggu. Contoh dalam penelitian ini didapatkan secara voluntary sampling sejumlah 249 orang dengan kriteria pengguna e-commerce yang berusia 18-65 tahun dan pernah mengalami ketidakpuasan dalam berbelanja menggunakan e-commerce. Analisis data menggunakan metode SEM melalui software LISREL 8.80. Hasil penelitian ini menunjukan adanya pengaruh negatif antara konsep diri dengan kerentanan konsumen dan pengetahuan pembelian terhadap konsumen. Konsep diri ditemukan tidak berpengaruh terhadap variabel pengetahuan pembelian., The presence of e-commerce provides a lot of convenience in shopping, but it cannot be denied that consumers will be close to losses and vulnerabilities due to business actors or consumer weaknesses. This study aims to analyze the factors that influence consumer vulnerability, especially for e-commerce users. These factors include self-concept and purchasing knowledge in the use of e-commerce. The research design used was a cross-sectional study. Selection of samples using non-probability with self-administered methods using online questionnaires. Data collection was carried out in March 2021 for three weeks. Examples in this study were obtained by the voluntary sampling of 249 people with the criteria of e-commerce users aged 18-65 years and had experienced dissatisfaction in shopping using e-commerce. Data analysis using SEM method through LISREL 8.80 software. The results of this study indicate a negative influence between self-concept and consumer vulnerability and purchasing knowledge to consumers. Self-concept was found to not affect purchasing knowledge variables.
Keyword: consumer vulnerability, e-commerce, purchasing knowledge, self-concept

Judul: The Influence of Motivation, Product Knowledge  and Self-Efficacy Towards Consumer Vulnerability of Credit Card Users
Abstrak: Pada tahun 2019, Yayasan Lembaga Konsumen Indonesia (YLKI) telah menerima 106 kasus pengaduan perbankan dengan 15,09% pengaduan bank mengenai kartu kredit. Pengaduan konsumen mengindikasikan adanya kerentanan konsumen. Kerentanan konsumen merupakan keterbatasan konsumen dalam asimilasi dan akses informasi sehingga rentan terhadap praktik tekanan pelaku usaha yang curang sehingga konsumen berpeluang mengalami risiko kerugian. Tujuan penelitian ini adalah untuk menganalisis pengaruh motivasi, pengetahuan produk dan efikasi diri terhadap kerentanan konsumen pengguna kartu kredit. Desain penelitian ini adalah cross sectional study. Pengambilan data dilakukan bulan Maret hingga April 2021 selama tiga minggu. Data diperoleh menggunakan kuesioner online dengan 205 responden. Analisis data menggunakan metode SEM melalui software LISREL 8.80. Hasil penelitian menunjukkan motivasi penggunaan kartu kredit responden, pengetahuan produk terkait kartu kredit, efikasi diri penggunaan kartu kredit dan kerentanan konsumen pengguna kartu kredit berada pada kategori sedang. Hasil penelitian menunjukkan kerentanan konsumen yang terdiri dari dimensi akses informasi, tekanan pelaku usaha dan risiko kerugian dipengaruhi oleh motivasi dan efikasi diri tetapi tidak dipengaruhi oleh pengetahuan produk. Motivasi dan efikasi diri berpengaruh positif terhadap seluruh variabel., In 2019, Yayasan Lembaga Konsumen Indonesia (YLKI) received 106 cases of bank complaints with 15,09% of bank complaints related to credit cards. Consumer complaints indicate consumer vulnerability. Consumer vulnerability is the limitation of consumers in assimilation and access to information so that they are vulnerable to fraudulent business pressure practices so that consumers have the opportunity to risk losses. The purpose of this study was to analyze the influence of motivation, product knowledge and consumer vulnerability to credit card users. The design used in this study was a cross sectional study. Data was collected from March to April 2021 for three weeks. The data was collected by using an online questionnaire with 205 respondents. Data analysis using SEM method through LISREL 8.80 software. The results showed that the respondents' motivation to use credit cards, credit card related product knowledge, self-efficacy of credit card use and consumer vulnerability of credit card users were in the ii medium category. The results showed that consumer vulnerability which consists of dimensions of access to information, seller pressure and risk of loss is influenced by motivation and self-efficacy but is not influenced by product knowledge. Motivation and self-efficacy have a positive effect on all variables.
Keyword: Access to Information, Consumer Vulnerability, Credit Cards, Risk of  Loss, Seller Pressure

Judul: Hydrothermal Synthesis of Biphasic Calcium Posphate
Abstrak: Biphasio calsium phosphate (BCP), which was a mixture of hydroxypatite (HA) and tricalcium phosphate (TCP), was synthesized by hydrothermal method followed by sintering process. Hydroxyapatite was produced by using natural calcium source CaO from hen's eggshell and (NH4)2HPO4 as phosphate souce, other hydroxyapatite sample was produce by using synthetic calcium source Ca(OH) and H3PO4 as phosphate source.
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